Monday, November 30, 2015
Cardiorespiratory fitness in young adults associated with lower risk of cardiovascular disease death
Cardiorespiratory fitness in young adults was associated with lower risk of cardiovascular disease and death but it was not associated with the development of coronary artery calcification in a long-term study of a large racially diverse group of U.S. adults, according to an article published online by JAMA Internal Medicine.
Cardiorespiratory fitness (CRF) has been associated with decreased risk for cardiovascular disease (CVD) in older adults but less is known about the role of CRF and its changes in young adulthood on long-term cardiovascular outcomes.
Joao A.C. Lima, M.D., of Johns Hopkins Medical School, Baltimore, Ravi V. Shah, Beth Israel Deaconess Medical Center, Boston, and Venkatesh L. Murthy, M.D., Ph.D., of the University of Michigan, Ann Arbor, and coauthors examined baseline CRF and changes in CRF in participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study in relation to future CVD.
The study included 4,872 adults (ages 18 to 30) who underwent treadmill exercise testing at baseline from March 1985 to June 1986 and 2,472 individuals who had a second treadmill test seven years later. During a median follow-up of nearly 27 years, participant assessments included obesity, left ventricular heart mass and strain(a measure of the strength of heart muscle contraction), coronary artery calcification (CAC) and incident CVD.
Among the 4,872 participants, 273 (5.6 percent) died and 193 (4 percent) experienced CVD events during follow-up. Among the deaths, 200 were noncardiovascular in origin and the greatest number of those (45 or 22.5 percent) were due to cancer. Also, 869 of 3,067 participants (28.3 percent) had any CAC by year 25, and 324 of 3,001 participants (10.8 percent) had left ventricular hypertrophy (a thickening of the heart muscle).
Exercise treadmill testing in the study consisted of as many as nine two-minute stages of gradually increasing difficulty. The study suggests each additional minute of baseline exercise test duration was associated with a 15 percent lower risk of death and a 12 percent lower risk of CVD. Each one-minute increase also was associated with reduced left ventricular mass and better strain. However, exercise test duration was not associated with CAC at year 15, 20 and 25.
A second treadmill assessment at seven years suggests that a one-minute reduction in fitness by year seven was associated with a 21 percent increased risk of death and a 20 percent increased risk of CVD. Each one-minute reduction was associated with worsening strain. No association between a change in fitness and CAC was found, according to the results.
"Efforts to evaluate and improve fitness in early adulthood may affect long-term health at the earliest stages in CVD pathogenesis," the authors conclude.
Commentary: Fitness in Young Adults Predictor of Risk for Cardiovascular Disease
"The present report draws attention to the substantive and independent value of physical activity and CRF [cardiorespiratory fitness] in CVD [cardiovascular disease] prevention regardless of age, race or sex, highlighting its significance as a tool for individuals and population-based intervention. Policies directed at promotion of physical activity in the population will have a significant effect on CVD morbidity and mortality," write David. E. Chiriboga, M.D., M.P.H., and Ira S. Ockene, M.D., of the University of Massachusetts Medical School, Worcester, in a related commentary.
Aspirin blocks cell death associated with Alzheimer's, Parkinson's and Huntington's disease
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A new study finds that a component of
aspirin binds to an enzyme called GAPDH, which is believed to play a major role
in neurodegenerative diseases, including Alzheimer's, Parkinson's and
Huntington's diseases.
Researchers at the Boyce Thompson
Institute and John Hopkins University discovered that salicylic acid, the
primary breakdown product of aspirin, binds to GAPDH, thereby stopping it from
moving into a cell's nucleus, where it can trigger the cell's death. The study,
which appears in the journal PLOS ONE, also suggests that derivatives of
salicylic acid may hold promise for treating multiple neurodegenerative
diseases.
Senior author Daniel Klessig, a
professor at Boyce Thompson Institute and Cornell University, has studied the
actions of salicylic acid for many years, but primarily in plants. Salicylic
acid is the critical hormone for regulating the plant immune system. Previous
studies have identified several targets in plants that are affected by
salicylic acid, and many of these targets have equivalents in humans.
In the new study, the researchers
performed high-throughput screens to identify proteins in the human body that
bind to salicylic acid. GAPDH (Glyceraldehyde 3-Phosphate Dehydrogenase) is a
central enzyme in glucose metabolism, but plays additional roles in the cell.
Under oxidative stress--an excess of free radicals and other reactive
compounds--GAPDH is modified and then enters the nucleus of neurons, where it
enhances protein turnover, leading to cell death.
The anti-Parkinson's drug deprenyl
blocks GAPDH's entry into the nucleus and the resulting cell death. The
researchers discovered that salicylic acid also is effective at stopping GAPDH
from moving into the nucleus, thus preventing the cell from dying.
"The enzyme GAPDH, long thought
to function solely in glucose metabolism, is now known to participate in
intracellular signaling," said co-author Solomon Snyder, professor of
neuroscience at Johns Hopkins University in Baltimore. "The new study
establishes that GAPDH is a target for salicylate drugs related to aspirin, and
hence may be relevant to the therapeutic actions of such drugs."
Furthermore, they found that a
natural derivative of salicylic acid from the Chinese medical herb licorice and
a lab-synthesized derivative bind to GAPDH more tightly than salicylic acid.
Both are more effective than salicylic acid at blocking GAPDH's movement into
the nucleus and the resulting cell death.
Earlier this year, Klessig's group
identified another novel target of salicylic acid called HMGB1 (High Mobility
Group Box 1), which causes inflammation and is associated with several
diseases, including arthritis, lupus, sepsis, atherosclerosis and certain
cancers. Low levels of salicylic acid block these pro-inflammatory activities,
and the above mentioned salicylic acid derivatives are 40 to 70 times more
potent than salicylic acid at inhibiting these pro-inflammatory activities.
"A better understanding of how salicylic acid and its
derivatives regulate the activities of GAPDH and HMGB1, coupled with the
discovery of much more potent synthetic and natural derivatives of salicylic
acid, provide great promise for the development of new and better salicylic
acid-based treatments of a wide variety of prevalent, devastating
diseases," said Klessig.
Sugar helps stave off tiredness in endurance exercise
It turns out a spoonful of sugar might not just help the medicine go down, but could also help stave off tiredness faced by weary marathon runners - or other long-distance athletes - when they hit the wall.
According to health researchers at the University of Bath, stirring in table sugar from the baking cupboard into a water bottle before a big physical event could be the difference between success and failure.
In their new study, published in the leading international journal the American Journal of Physiology - Endocrinology & Metabolism, the scientists assessed the impact of endurance exercise on liver glycogen levels (stored carbohydrates in the body) and tested what could be done to prevent fatigue.
They tested various sucrose- and glucose-based drinks to see how different carbohydrates could help. Their experiment, conducted on long-distance cyclists, showed that ingesting carbohydrates in the form of either glucose or sucrose prevents the decline in liver glycogen 'carbohydrate stores' and can avert tiredness.
Both sucrose - in the form of table sugar - and glucose are important carbohydrates often referred to as 'simple sugars'. The major difference between them is that each sucrose molecule is made up of one glucose and one fructose molecule linked together. It appears combining different sources of sugars improves the rate at which we can absorb these from the gut.
Although an increasing number of sports-performance drinks designed to provide energy during exercise now use sucrose, or mixtures of glucose and fructose, many still rely on glucose alone. The researchers warn that such glucose-only drinks could produce gut discomfort and suggest sucrose-based alternatives, or sugar in water, can help make exercise easier.
Lead researcher Dr Javier Gonzalez explained: "The carbohydrate stores in our liver are vitally important when it comes to endurance exercise as they help us to maintain a stable blood sugar level. However, whilst we have a relatively good understanding of the changes in our muscle carbohydrate stores with exercise and nutrition, we know very little about optimising liver carbohydrate stores during and after exercise.
"Our study showed that ingesting carbohydrates during exercise can prevent the depletion of carbohydrate stores in the liver but not in muscle. This may be one of the ways in which carbohydrate ingestion improves endurance performance.
"We also found that the exercise felt easier, and the gut comfort of the cyclists was better, when they ingested sucrose compared to glucose. This suggests that, when your goal is to maximise carbohydrate availability, sucrose is probably a better source of carbohydrate to ingest than glucose."
The scientists behind the new study recommend that if your goal is optimal performance during exercise lasting over two and half hours then consume up to 90g of sugar per hour - diluted to 8g sugar per 100ml.
To find out more about this work and read the study 'Ingestion of Glucose or Sucrose Prevents Liver but not Muscle Glycogen Depletion During Prolonged Endurance-type Exercise in Trained Cyclists' see http://dx.doi.org/10.1152/ajpendo.00376.2015.
Friday, November 27, 2015
Elevated weight in early adulthood associated with increased risk of sudden cardiac death
Overweight and obesity throughout adulthood,
and especially elevated weight in early adulthood, were associated with
increased risk of sudden cardiac death in a 32-year study of more than
72,000 women published today in JACC: Clinical Electrophysiology.
"We found that it is important to maintain a healthy weight
throughout adulthood as a way to minimize the risk of sudden cardiac
death," said Stephanie Chiuve, Sc.D., assistant professor of medicine at
Harvard Medical School and lead author of the study. Excess weight or
substantial weight gain may have an early or cumulative impact on the
risk of sudden cardiac death that is not completely erased by weight
loss later in life, the author said.Researchers analyzed data from the Nurses' Health study, following 72,484 healthy women from 1980 to 2012. Participants provided information on their height and weight at the start of the study, as they remembered it at age 18, and through questionnaires administered every two years during the study period.
The study examined the relation between body mass index (BMI) and weight gain and the risk for sudden cardiac death, death from coronary heart disease and non-fatal heart attacks. Over the 32-year study period, researchers documented 445 cases of sudden cardiac death, 1,286 cases of fatal coronary heart disease, and 2,272 non-fatal heart attacks.
Body mass index is a person's weight in relation to their height and is used to screen for overweight and obesity. Sudden cardiac death is a sudden, unexpected death usually precipitated by a lethal chaotic cardiac rhythm resulting in a loss of heart function. Sudden cardiac death is often the first manifestation of heart disease in women.
Women with a higher BMI during adulthood had a greater risk of sudden cardiac death. Women who were overweight (BMI 25-30) and obese (BMI 30 or greater) were respectively 1.5- and 2-times more likely to experience sudden cardiac death over the next two years as compared to women with a healthy weight (BMI 21-23). Women who were overweight or obese at the start of the study or obese at age 18 had an elevated risk of sudden cardiac death over the entire course of the study.
Researchers also found that weight gain in early-to-mid adulthood was associated with greater risk of sudden cardiac death regardless of BMI at age 18. The risk of sudden cardiac death was twice as high in women who gained 44 pounds or more during early to mid-adulthood.
"Nearly three-quarters of all sudden cardiac deaths occur in patients not considered to be high-risk based on current guidelines. We must seek broader prevention strategies to reduce the burden of sudden cardiac death in the general population," Chiuve said.
Women with a higher BMI had a greater risk of fatal coronary heart disease and non-fatal heart attacks, although the association was weaker compared with sudden cardiac death.
"This study adds to a growing body of evidence that the adverse effects of obesity on cardiac rhythm, in this case, sudden death risk, begin in early adulthood. It underscores the need for earlier identification and treatment of high risk individuals," said David J. Wilber, M.D., editor-in-chief of JACC: Clinical Electrophysiology.
Observational studies such as this one cannot determine cause and effect, and factors not measured could impact the results, though this study controlled for numerous clinical and lifestyle factors. The Nurses' Health Study includes a population of educated, primarily white women and may not apply to other ethnic groups. All studies with self-reported measures have some degree of error.
Heart disease patients who sit a lot have worse health even if they exercise
Patients with heart disease who sit a lot have worse health even if they exercise, reveals research from the University of Ottawa Heart Institute, and published in the European Journal of Cardiovascular Prevention.
"Get up and move every 30 minutes to improve health."
"Limiting the amount of time we spend sitting may be as important as the amount we exercise," said lead author Dr Stephanie Prince, post-doctorate fellow in the Division of Prevention and Rehabilitation, University of Ottawa Heart Institute. "Sitting, watching TV, working at a computer and driving in a car are all sedentary behaviours and we need to take breaks from them."
Previous research has shown that being sedentary increases the risk of cardiovascular disease but until now its effect on patients with established heart disease was unknown.
The current study investigated levels of sedentary behaviour and the effect on health in 278 patients with coronary artery disease. The patients had been through a cardiac rehabilitation programme which taught them how to improve their levels of exercise in the long term.
Patients wore an activity monitor during their waking hours for nine days. The monitors allowed the researchers to measure how long patients spent being sedentary, or doing light, moderate or vigorous levels of physical activity.
The researchers also assessed various markers of health including body mass index (BMI, in kg/m2) and cardiorespiratory fitness. Next they looked at whether the amount of time a person spent being sedentary (which was mainly sitting) was related to these markers of health.
The researchers found that patients with coronary artery disease spent an average of eight hours each day being sedentary. "This was surprising given that they had taken classes on how to exercise more," said Dr Prince. "We assumed they would be less sedentary but they spent the majority of their day sitting."
Men spent more time sitting than women - an average of one hour more each day. This was primarily because women tended to do more light intensity movement - things like light housework, walking to the end of the drive, or running errands.
Dr Prince said: "Women with coronary artery disease spend less time sitting for long periods but we need to do more research to understand why. There is some research from the past which suggests that at around the age of 60 men become more sedentary than women and may watch more TV."
The researchers found that patients who sat more had a higher BMI. They also had lower cardiorespiratory fitness, which was assessed using VO2 peak. This is the maximum rate at which the heart, lungs and muscles use oxygen during an exercise test (also called aerobic capacity).
"These relationships remained even when we controlled for an individual's age, gender or physical activity levels," said Dr Prince. "In other words, people who sat for longer periods were heavier and less fit regardless of how much they exercised."
Practical tips to get moving:
- Get up and move every 30 minutes
- Stand up during TV commercials or, even better, do light exercises while watching TV
- Set a timer and take regular breaks from your desk
- Take lunch breaks outside instead of in front of the computer
- Go to bed instead of sitting in front of the TV and get the benefits of sleeping
- Monitor your activity patterns to find out when you are most sedentary.
Dr Prince emphasized that sitting less was not a replacement for exercise. "It's important to limit prolonged bouts of sitting and in addition to be physically active," she said. "Sedentary time may be another area of focus for cardiac rehabilitation programmes along with exercise."
Tuesday, November 24, 2015
Stored fat fights against the body's attempts to lose weight
The fatter we are, the more our body appears to produce a protein that inhibits our ability to burn fat, suggests new research published in the journal Nature Communication. The findings may have implications for the treatment of obesity and other metabolic diseases.
Most of the fat cells in the body act to store excess energy and release it when needed but some types of fat cells, known as brown adipocytes, function primarily for a process known as thermogenesis, which generates heat to keep us warm. However, an international team of researchers from the Wellcome Trust-Medical Research Council Institute of Metabolic Sciences at the University of Cambridge, UK, and Toho University, Japan, have shown that a protein found in the body, known as sLR11, acts to suppress this process.
Researchers investigated why mice that lacked the gene for the production of this protein were far more resistant to weight gain. All mice - and, in fact, humans - increase their metabolic rate slightly when switched from a lower calorie diet to a higher calorie diet, but mice lacking the gene responded with a much greater increase, meaning that they were able to burn calories faster.
Further examinations revealed that in these mice, genes normally associated with brown adipose tissue were more active in white adipose tissue (which normally stores fat for energy release). In line with this observation, the mice themselves were indeed more thermogenic and had increased energy expenditure, particularly following high fat diet feeding.
The researchers were able to show that sLR11 binds to specific receptors on fat cells - in the same way that a key fits into a lock - to inhibit their ability to activate thermogenesis. In effect, sLR11 acts as a signal to increase the efficiency of fat to store energy and prevents excessive energy loss through unrestricted thermogenesis.
When the researchers examined levels of sLR11 in humans, they found that levels of the protein circulating in the blood correlated with total fat mass - in other words, the greater the levels of the protein, the higher the total fat mass. In addition, when obese patients underwent bariatric surgery, their degree of postoperative weight loss was directly proportional to the reduction in their sLR11 levels, suggesting that sLR11 is produced by fat cells.
In their paper the authors suggest that sLR11 helps fat cells resist burning too much fat during 'spikes' in other metabolic signals following large meals or short term drops in temperature. This in turn makes adipose tissue more effective at storing energy over long periods of time.
There is growing interest in targeting thermogenesis with drugs in order to treat obesity, diabetes and other associated conditions such as heart disease. This is because it offers a mechanism for disposing of excess fat in a relatively safe manner. A number of molecules have already been identified that can increase thermogenesis and/or the number of fat cells capable of thermogenesis. However to date there have been very few molecules identified that can decrease thermogenesis.
These findings shed light on one of the mechanisms that the body employs to hold onto stored energy, where sLR11 levels increase in line with the amount of stored fat and act to prevent it being 'wasted' for thermogenesis.
Dr Andrew Whittle, joint first author, said: "Our discovery may help explain why overweight individuals find it incredibly hard to lose weight. Their stored fat is actively fighting against their efforts to burn it off at the molecular level."
Professor Toni Vidal-Puig, who led the team, added: "We have found an important mechanism that could be targeted not just to help increase people's ability to burn fat, but also help people with conditions where saving energy is important such as anorexia nervosa."
Jeremy Pearson, Associate Medical Director at the British Heart Foundation (BHF), which helped fund the research, said: "This research could stimulate the development of new drugs that either help reduce obesity, by blocking the action of this protein, or control weight loss by mimicking its action. Based on this promising discovery, we look forward to the Cambridge team's future findings.
"But an effective medicine to treat obesity, which safely manages weight loss is still some way off. In the meantime people can find advice on healthy ways to lose weight and boost their heart healthy on the BHF website - bhf.org.uk."
Study links physical activity to better memory among older adults
Could staying physically active improve quality of life by delaying cognitive decline and prolonging an independent lifestyle? A new study has found that older adults who take more steps either by walking or jogging perform better on memory tasks than those who are more sedentary.
The study examines the relationship between physical activity, memory and cognition in young and old adults. It appears online in the Journal of the International Neuropsychological Society.
The study included 29 young adults (ages 18-31) and 31 older adults (ages 55-82) who wore a small device called an ActiGraph, which recorded information including how many steps each took, how vigorous the steps were and how much time it involved. Participants also completed neuropsychological testing to assess their memory, planning and problem-solving abilities. In addition to standardized neuropsychological tasks of executive function (planning and organization abilities) and long-term memory, participants engaged in a laboratory task in which they had to learn face-name associations.
The researchers found that older adults who took more steps per day had better memory performance. The association between the number of steps taken was strongest with a task that required recalling which name went with a person's face--the same type of everyday task that older adults often have difficulty with. In young adults, the number of steps taken was not associated with memory performance.
According to the researchers these findings demonstrate that the effects of physical activity extend to long-term memory--the same type of memory that is negatively impacted by aging and neurodegenerative dementias such as Alzheimer's disease. ''Our findings that physical activity is positively associated with memory is appealing for a variety of reasons. Everyone knows that physical activity is a critical component to ward off obesity and cardiovascular-related disease. Knowing that a lack of physical activity may negatively impact one's memory abilities will be an additional piece of information to motivate folks to stay more active," explained corresponding author Scott Hayes, PhD, assistant professor of psychiatry at Boston University School of Medicine and the Associate Director of the Neuroimaging Research for Veterans Center at the VA Boston Healthcare System.
The authors point out that staying physically active can take a variety of forms from formal exercise programs to small changes, such as walking or taking the stairs. "More research is needed to explore the specific mechanisms of how physical activity may positively impact brain structure and function as well as to clarify the impact of specific exercise programs (e.g., strength, aerobic, or combined training) or dose of exercise (frequency, intensity, duration) on a range of cognitive functions,'' added Hayes.
The authors emphasize that the objective measurement of physical activity was a key component of the current study, as the majority of studies to date have used self-report questionnaires, which can be impacted by memory failures or biases.
Monday, November 23, 2015
Higher resting heart rate linked to increased risk of death from all causes - Absolute risk is still small
A higher resting heart rate is associated with an increased risk of death from all causes in the general population, even in people without the usual risk factors for heart disease, according to new research published in CMAJ (Canadian Medical Association Journal).
"The association of resting heart rate with risk of all-cause and cardiovascular mortality is independent of traditional risk factors of cardiovascular disease, suggesting that resting heart rate is a predictor of mortality in the general population," writes Dr. Dongfeng Zhang, Medical College of Qingdao University, Shandong, China, with coauthors.
Current evidence for resting heart rate and risk of death and risk of death from heart disease is inconsistent. To understand if resting heart rate is correlated with an increased risk of death, researchers assessed 46 studies involving 1 246 203 patients and 78 349 deaths from all causes, and 848 320 patients and 25 800 deaths from heart disease.
"Results from this meta-analysis suggest the risk of all-cause and cardiovascular mortality increased by 9% and 8% for every 10 beats/min increment of resting heart rate," write the authors. "The risk of all-cause mortality increased significantly with increasing resting heart rate in a linear relation, but a significantly increased risk of cardiovascular mortality was observed at 90 beats/min ... consistent with the traditionally defined tachycardia threshold of 90 or 100 beats/min for prevention of cardiovascular disease."
The authors found that people with a resting heart rate of more than 80 beats/min had a 45% higher risk of death from any cause than those with a resting heart rate of 60-80 beats/min, who had a 21% increased risk. However, the absolute risk is still small. Findings were similar for people with cardiovascular risk factors.
"The available evidence does not fully establish resting heart rate as a risk factor, but there is no doubt that elevated resting heart rate serves as a marker of poor health status," states Dr. Zhang. "Our results highlight that people should pay more attention to their resting heart rate for their health, and also indicate the potential importance of physical activity to lower resting heart rate."
The authors note the limitation that various factors can affect measurement of resting heart rate and that nighttime heart rate could be a better risk predictor.
"The magnitude of association between resting heart rate and all-cause mortality was stronger than that with cardiovascular mortality, and this discrepancy can be expected because resting heart rate has been also found to be associated with noncardiovascular mortality," write the authors.
They call for more research to develop an algorithm that considers both resting heart rate and cardiovascular risk factors to help doctors assess resting heart rate in clinical care.
Soccer is good for old bones
Football is an effective type of training to promote musculoskeletal health. The FC Prostate study showed that the number of times the players accelerate and brake during football training is correlated to the changes in leg bone mass. Being challenged by an opponent, changing direction, kicking and blocking the ball provide a wide range of powerful stimuli to the bone tissue, making the bones stronger.
Photo: Bo Kousgaard, Copenhagen Centre for Team Sport and Health.
Thursday, November 19, 2015
Improving fitness may counteract brain atrophy in older adults,
Older adults that improved their fitness through a moderate intensity exercise program increased the thickness of their brain's cortex, the outer layer of the brain that typically atrophies with Alzheimer's disease, according to a new study from the University of Maryland School of Public Health. These effects were found in both healthy older adults and those diagnosed with mild cognitive impairment (MCI), an early stage of Alzheimer's disease.
"Exercise may help to reverse neurodegeneration and the trend of brain shrinkage that we see in those with MCI and Alzheimer's," says Dr. J. Carson Smith, associate professor of kinesiology and senior author of the study, published in the Journal of the International Neuropsychological Society on Nov. 19, 2015. "Many people think it is too late to intervene with exercise once a person shows symptoms of memory loss, but our data suggest that exercise may have a benefit in this early stage of cognitive decline."
The previously physically inactive participants (ages 61-88) were put on an exercise regimen that included moderate intensity walking on a treadmill four times a week over a twelve-week period. On average, cardiorespiratory fitness improved by about 8% as a result of the training in both the healthy and MCI participants.
The atrophy of the brain's cortical layer is a marker of Alzheimer's disease progression and correlates with symptoms including cognitive impairment. Dr. Smith and colleagues found that the study participants who showed the greatest improvements in fitness had the most growth in the cortical layer, including both the group diagnosed with MCI and the healthy elders. While both groups showed strong associations between increased fitness and increased cortical thickness after the intervention, the MCI participants showed greater improvements compared to healthy group in the left insula and superior temporal gyrus, two brain regions that have been shown to exhibit accelerated neurodegeneration in Alzheimer's disease.
Dr. Smith previously reported that the participants in this exercise intervention showed improvements in neural efficiency during memory recall, and these new data add to the evidence for the positive impact of exercise on cognitive function. Other research he has published has also shown that moderate intensity physical activity, such as walking for 30 minutes 3-4 days per week, may protect brain health by staving off shrinkage of the hippocampus in older adults.
This is the first study to show that exercise and improved fitness can impact cortical thickness in older adults diagnosed with mild cognitive impairment. Dr. Smith plans future studies that include more participants engaging in a longer-term exercise intervention to see if greater improvements can be seen over time, and if the effects persist over the long term. The key unanswered question is if regular moderate intensity physical activity could reverse or delay cognitive decline and help keep people out of nursing homes and enable them to maintain their independence as they age.
Walking faster or longer linked to significant cardiovascular benefits in older adults
In a large prospective community-based study of older Americans, modest physical activity was associated with a lower risk of cardiovascular disease (CVD). This was true even among men and women older than age 75 at baseline - a rapidly growing population for whom regular activity has been advised, but with little supportive empirical evidence.
Led by senior author, Dariush Mozaffarian, M.D., Dr.P.H., dean of the Friedman School of Nutrition Science and Policy at Tufts University, the researchers studied a group of American adults whose mean age was 73 at the start of the study and who were then followed for 10 years. Information on various usual activities was assessed at baseline and regularly updated during follow-up. When the current study's research team evaluated different aspects of physical activity by the men and women during this ten-year period -- a greater pace, walking distance, and leisure activity-- each was associated with a lower risk of cardiovascular disease. The associations found include:
- After adjustment for other risk factors and lifestyle behaviors, those who were more active had significantly lower risk of future heart attacks and stroke.
- Adults who walked at a pace faster than three miles per hour (mph) had a 50%, 53%, 50% lower risk of coronary heart disease (CHD), stroke and total CVD, respectively, compared to those who walked at a pace of less than two mph.
- Those who walked an average of seven blocks per day or more had a 36%, 54% and 47% lower risk of CHD, stroke and total CVD, respectively, compared to those who walked up to five blocks per week.
- Those who engaged in leisure activities such as lawn-mowing, raking, gardening, swimming, biking and hiking, also had a lower risk of CHD, stroke and total CVD, compared to those who did not engage in leisure-time activities.
The researchers studied 4,207 men and women who had been enrolled in the Cardiovascular Health Study (CHS). CHS is a National Heart, Lung, and Blood Institute of the National Institutes of Health-supported national cohort of U.S. men and women who were enrolled in 1989-90 from Medicare eligibility lists and whose health was followed over time. The researchers used the information in the CHS database concerning physical activity, including walking, leisure-time activities and exercise intensity, and other health information coming from annual study visits such as physical exams, diagnostic testing, laboratory evaluations, personal health histories, and measured risk factors.
"Our study of older Americans shows that, even late in life, moderate physical activity such as walking is linked to lower incidence of cardiovascular disease," commented the first author Luisa Soares-Miranda, Ph.D., a member of the research team and currently a postdoctoral student with the Research Centre in Physical Activity, Health and Leisure, Faculty of Sport at the University of Porto, Portugal. "It appears that whether one increases the total distance or the pace of walking, CVD risk is lowered. Fortunately, walking is an activity that many older adults can enjoy."
"While national guidelines recommend that older adults engage in regular physical activity, surprisingly few studies have evaluated potential cardiovascular benefits after age 75, a rapidly growing age group," said Mozaffarian. "Our findings confirm a beneficial relationship between walking and leisure activities and CVD late in life. These results are especially relevant because, with advancing age, the ability to perform vigorous types of activity often decreases. Our findings support the importance of continuing light to moderate exercise to improve health across the lifespan."
Wednesday, November 18, 2015
Working up a sweat may protect men from lethal prostate cancer
A study that tracked tens of thousands of midlife and older men for more than 20 years has found that vigorous exercise and other healthy lifestyle habits may cut their chances of developing a lethal type of prostate cancer by up to 68 percent.
While most prostate cancers are 'clinically indolent,' meaning they do not metastasize and are nonlife-threatening, a minority of patients are diagnosed with aggressive disease that invades the bone and other organs, and is ultimately fatal. Lead author Stacey Kenfield, ScD, of UCSF, and a team of researchers at UCSF and Harvard, focused on this variant of prostate cancer to determine if exercise, diet and smoke-free status might have life-saving benefits.
In the study, published today, Nov. 17, 2015, in the Journal of the National Cancer Institute, the researchers analyzed data from two U.S. studies: the Health Professionals Follow-Up Study that tracked more than 42,000 males ages 40 to 75, from 1986 to 2010; and a second, the Physicians' Health Study that followed more than 20,000 males ages 40 to 84, from 1982 to 2010.
To gage the effects of lifestyle habits, the researchers developed a score based on the results of the health professionals survey, then applied it to the physicians' study. They assigned one point for each affirmative response to questions about regular intense exercise that induced sweating, body mass index (BMI) under 30, tobacco-free status for a minimum of 10 years, high intake of fatty fish, high intake of tomatoes and low intake of processed meat.
To reduce error, participants had to be free of diagnosed cancer at the start of the study and a four-year lag was imposed to rule out those who unknowingly had lethal prostate cancer, which was determined by evidence of 'prostate cancer death or metastasis to the bones or other organs, excluding the lymph nodes.' Cases were confirmed through medical records and pathology reports, and cause of death was determined by death certificate and medical record, and secondarily by next of kin.
Vigorous activity trumps other lifestyle factors
The researchers identified 576 cases of lethal prostate cancer in the health professionals' group and 337 cases in the physicians' group. Participants with 5 to 6 points in the health professionals' group had a 68 percent decreased risk of lethal prostate cancer and a 38 percent decreased risk was observed in the physicians' group for the same comparison. For dietary factors alone, men with three points, versus those with zero points, had a 46 percent decreased chance of developing lethal prostate cancer in the health professionals' group. In the physicians' group this decrease was 30 percent.
While there were fewer cases and less detailed data collected in the physicians' study, the score was similar in both populations, indicating the potential benefit of healthy lifestyle habits in warding off lethal prostate cancer, said the authors.
"We estimated that 47 percent of lethal prostate cancer cases would be prevented in the United States if men over 60 had five or more of these healthy habits," said Kenfield, assistant professor in the Department of Urology at UCSF Medical Center, and formerly of the Department of Medicine at Harvard Medical School in Boston, where the study was initiated.
"It's interesting that vigorous activity had the highest potential impact on prevention of lethal prostate cancer. We calculated the population-attributable risk for American men over 60 and estimated that 34 percent of lethal prostate cancer would be reduced if all men exercised to the point of sweating for at least three hours a week," Kenfield said.
The researchers also calculated that lethal prostate cancer among American men over 60 would be cut by 15 percent if they consumed at least seven servings of tomatoes per week and that 17 percent would be spared this diagnosis if they consumed at least one serving of fatty fish per week. Reducing intake of processed meats would cut the risk by 12 percent, they reported. In contrast, the population-attributed risk for smoking was 3 percent, largely because the majority of older American men are long-term nonsmokers.
Lifestyle changes also prevent heart disease, diabetes
"This study underscores the ongoing need for more effective prevention measures and policies to increase exercise, improve diet quality and reduce tobacco use in our population," said senior author June M. Chan, ScD, from the departments of Urology, and Epidemiology and Biostatistics at UCSF. "It takes co-operation and effort from multiple areas, like insurance companies, employers, policy makers and city planners, to figure out how to creatively support and encourage more exercise into most busy adults' working day. These lifestyle habits align with other recommendations to prevent diabetes and heart disease."
About one man in seven will be diagnosed with prostate cancer during his lifetime, making it the most frequently diagnosed cancer in the United States, excluding non-melanoma skin cancer. According to the American Cancer Society, in 2015 there will be approximately 220,800 cases of prostate cancer and approximately 27, 540 deaths.
Light therapy effective for non-SAD depression
New research finds that light therapy can treat non-seasonal depression and improve the overall wellbeing of people suffering from the disease.
"These results are very exciting because light therapy is inexpensive, easy to access and use, and comes with few side effects," said Dr. Raymond Lam, a UBC professor and psychiatrist at the Djavad Mowafaghian Centre for Brain Health, a partnership between UBC and Vancouver Coastal Health. "Patients can easily use light therapy along with other treatments such as antidepressants and psychotherapy."
The research, published today in JAMA Psychiatry, is the first placebo-controlled trial that shows that light therapy is an effective treatment for depression that is not brought on by seasonal affective disorder.
Lam and his colleagues followed 122 patients and evaluated whether light therapy improved the mood of patients when it was used both with and without the commonly prescribed antidepressant fluoxetine. Light therapy involved 30 minutes of exposure to a fluorescent light box soon after waking up every day for eight weeks. Some study participants were given placebo pills and placebo devices instead of the real therapies. The researchers found that light therapy helped many patients and provided the most benefit to those who were also taking antidepressants.
Depression affects one in 20 people and is among the leading causes of disability worldwide.
Depression can cause significant problems in family and personal relationships, work attendance and productivity, and overall quality of life. It is also associated with an increased risk of death.
According to the researchers, medications are effective for treating depression but only work in about 60 per cent of cases.
"More and more people are seeking help because there is less stigma about having depression," said Lam. "It's important to find new treatments because our current therapies don't work for everyone. Our findings should help to improve the lives of people with depression."
Bright light treatment either alone or combined with an antidepressant was an effective and well tolerated treatment for adults with nonseasonal major depressive disorder (MDD) in a randomized clinical trial, according to an article published online by JAMA Psychiatry.
MDD is among the leading causes of disability worldwide and is associated with impaired quality of life and an increased risk of death. Treatments include psychotherapies and antidepressants but remission rates remain low so more therapeutic options are needed. Light therapy has been effective treatment for seasonal affective disorder (SAD).
Raymond W. Lam, M.D., of the University of British Columbia, Vancouver, Canada, and coauthors conducted a double-blind and placebo-and-sham-controlled trial to test the efficacy of light treatment alone and in combination with fluoxetine hydrochloride compared with a placebo treatment involving an inactive device and a placebo pill.
The eight-week trial randomized 122 patients: light therapy (30 minutes/daily exposure to a fluorescent light box as soon as possible after awakening) and placebo pill (n=32); fluoxetine (20 mg/daily) and placebo device (a negative ion generator, n=31); combination light and fluoxetine treatment (n=29); or placebo device and placebo pill (n=30). The change in a common depression rating scale score was the study's primary outcomes.
The authors report combination therapy and light therapy alone were superior to placebo but fluoxetine alone was not superior to placebo.
Why light therapy appears to work is still unknown but hypotheses in SAD involve resynchronizing circadian rhythms. Nonseasonal MDD also may be associated with disturbances in the circadian rhythms, according to the authors.
College studies may reduce risk of dementia for older adults
Older adults who take college courses may increase their cognitive capacity and possibly reduce their risk for developing Alzheimer's disease or other forms of dementia, according to new research published by the American Psychological Association.
An Australian study called the Tasmanian Healthy Brain Project recruited 359 participants ages 50 to 79 who took a series of cognitive tests before completing at least a year of full-time or part-time study at the University of Tasmania. Participants were reassessed annually for three years following their studies. More than 90 percent of the participants displayed a significant increase in cognitive capacity, compared with 56 percent in a control group of 100 participants who didn't take any college courses.
"The study findings are exciting because they demonstrate that it's never too late to take action to maximize the cognitive capacity of your brain," said lead researcher Megan Lenehan, PhD. "We plan to follow these participants as they age to see if college studies could help delay the onset or reduce the debilitating effects of dementia."
Previous studies have examined how exercise, brain games and an active social life may boost cognitive capacity and possibly stem cognitive decline associated with aging. This study is the first to examine similar positive effects from college courses taken by older adults, said Lenehan, of the University of Tasmania.
The study participants, who were screened to exclude people who had dementia, completed a baseline series of tests to measure cognitive capacity, or an individual's ability to use brain networks efficiently in areas such as memory, information processing, decision making and planning. The participants in the college studies group took a wide range of courses, including history, psychology, philosophy and fine art. Most of the students took courses on campus, but some completed online classes. The researchers suspect that campus study may provide greater benefits in boosting cognitive capacity because of social interaction with professors and fellow students, but the study didn't analyze any differences between on-campus or online courses.
The participants completed the same cognitive tests each year during the four-year study, with 92 percent of the college-studies group displaying a significant increase in cognitive capacity, while the remaining 8 percent generally maintained their cognitive capacity. For the control group, 56 percent displayed a significant increase in cognitive capacity, while 44 percent had no change. The participants' age, gender, feelings of well-being or level of social connectedness didn't affect the findings. The research was published online in the journal Neuropsychology.
Prior research has shown that college study earlier in life may increase cognitive capacity, and it appears the same may be true for older adults, Lenehan said.
"It is possible that any mentally stimulating activity later in life may also enhance cognitive capacity, such as other adult-education classes or programs to increase social interaction," she said.
The control group was significantly older than the college studies group, but there were no significant differences in baseline cognitive capacity scores, the study noted. The researchers also didn't find any correlation between age and cognitive capacity scores at any point during the study. Some participants in the control group may have been doing crossword puzzles or other mentally stimulating activities that boosted their cognitive capacity, Lenehan said.
The participants who took college classes volunteered for the study so they probably had a greater interest in continuing education that the general senior population, the journal article noted. The study was too short to reveal any long-term effects so the researchers plan to follow the participants as they age to provide additional evidence of whether college studies may reduce the risk or delay the onset of dementia.
Going barefoot: Strong 'foot core' could prevent plantar fasciitis, shin splints, and other common injuries
As
your cold-weather footwear makes the seasonal migration from the back of your
closet to replace summer's flip flops and bare feet, don't underestimate the
benefits of padding around naked from the ankles down.
Barefoot
activities can greatly improve balance and posture and prevent common injuries
like shin splints, plantar fasciitis, stress fractures, bursitis, and
tendonitis in the Achilles tendon, according to Patrick McKeon, a professor in
Ithaca College's School of Health Sciences and Human Performance.
The
small, often overlooked muscles in the feet that play a vital but
underappreciated role in movement and stability. Their role is similar to that
of the core muscles in the abdomen.
"If
you say 'core stability,' everyone sucks in their bellybutton," he said.
Part of the reason why is about appearance, but it's also because a strong core
is associated with good fitness. The comparison between feet and abs is
intentional on McKeon's part; he wants people to take the health of their
"foot core" just as seriously.
The
foot core feedback loop
McKeon
describes a feedback cycle between the larger "extrinsic" muscles of
the foot and leg, the smaller "intrinsic" muscles of the foot, and
the neural connections that send information from those muscle sets to the
brain.
"Those
interactions become a very powerful tool for us," he said. When that
feedback loop is broken, though, it can lead to the overuse injuries that
plague many an athlete and weekend warrior alike.
Shoes
are the chief culprit of that breakdown, according to McKeon. "When you
put a big sole underneath, you put a big dampening effect on that information.
There's a missing link that connects the body with the environment," he
said.
Muscles
serve as the primary absorbers of force for the body. Without the nuanced
information provided by the small muscles of the foot, the larger muscles
over-compensate and over-exert past the point of exhaustion and the natural
ability to repair. When the extrinsic muscles are no longer able to absorb the
forces of activity, those forces are instead transferred to the bones, tendons,
and ligaments, which leads to overuse injuries.
It's
not that McKeon is opposed to footwear. "Some shoes are very good, from
the standpoint of providing support. But the consequence of that support, about
losing information from the foot, is what we see the effects of [in overuse
injuries]."
Strengthening
the foot core
The
simplest way to reintroduce the feedback provided by the small muscles of the
foot is to shed footwear when possible. McKeon says activities like Pilates,
yoga, martial arts, some types of dance, etc. are especially beneficial.
"Anything
that has to deal with changing postures and using the forces that derive from
the interaction with the body and the ground [is great for developing foot core
strength]," he said.
McKeon
also described the short-foot exercise, which targets the small muscles by
squeezing the ball of the foot back toward the heel. It's a subtle motion, and
the toes shouldn't curl when performing it. The exercise can be done anywhere
while seated or standing, though he recommends first working with an athletic
trainer or physical therapist to get familiar with the movement.
He
notes the exercise seems to have especially positive results for patients
suffering from ankle sprain, shin splints, and plantar fasciitis. It's even
been shown to improve the strain suffered by individuals with flat feet.
The
payoff could be more than just physical, as there could be financial savings.
With strong feet, McKeon suggests that -- depending on the activity --
consumers may not need to invest hundreds of dollars in slick, well-marketed
athletic sneakers (though he doesn't recommend going for the cheapest of cheap
sneakers, either). People with a strong foot core can actively rely on the foot
to provide proper support, rather than passively relying on the shoes alone.
"You
might be able to get a $50 pair of basketball shoes that don't have the typical
support that you'd expect. Because you have strong feet, you're just using the
shoes to protect the feet and grip the ground," he said.
The
easiest way to get started on strengthening the small muscles of the foot,
though, is to kick off your shoes in indoor environments.
"The
more people can go barefoot, such as at home or the office, is a really good
thing," McKeon said.
Tuesday, November 17, 2015
Moderate coffee drinking lowers risk of premature death
People who drink about three to five cups of coffee a day may be less likely to die prematurely from some illnesses than those who don't drink or drink less coffee, according to a new study by Harvard T.H. Chan School of Public Health researchers and colleagues. Drinkers of both caffeinated and decaffeinated coffee saw benefits, including a lower risk of death from cardiovascular disease, neurological diseases, type 2 diabetes, and suicide.
"Bioactive compounds in coffee reduce insulin resistance and systematic inflammation," said first author Ming Ding, a doctoral student in the Department of Nutrition. "That could explain some of our findings. However, more studies are needed to investigate the biological mechanisms producing these effects."
The study will appear online in Circulation on November 16, 2015.
Researchers analyzed health data gathered from participants in three large ongoing studies: 74,890 women in the Nurses' Health Study; 93,054 women in the Nurses' Health Study 2; and 40,557 men in the Health Professionals Follow-up Study. Coffee drinking was assessed using validated food questionnaires every four years over about 30 years. During the study period, 19,524 women and 12,432 men died from a range of causes.
In the whole study population, moderate coffee consumption was associated with reduced risk of death from cardiovascular disease, diabetes, neurological diseases such as Parkinson's disease, and suicide. Coffee consumption was not associated with cancer deaths. The analyses took into consideration potential confounding factors such as smoking, body mass index, physical activity, alcohol consumption, and other dietary factors.
"This study provides further evidence that moderate consumption of coffee may confer health benefits in terms of reducing premature death due to several diseases," said senior author Frank Hu, professor of nutrition and epidemiology. "These data support the 2015 Dietary Guidelines Advisory Report that concluded that 'moderate coffee consumption can be incorporated into a healthy dietary pattern.'"
Monday, November 16, 2015
Impact of high-fat diet on red blood cells may cause cardiovascular disease
University of Cincinnati (UC) researchers have discovered the negative impact a high fat diet has on red blood cells and how these cells, in turn, promote the development of cardiovascular disease.
This is one of the first studies to demonstrate the effect of red blood cells on the disease and could also affect the way patients with other health conditions, like cancer, who are prone to developing cardiovascular issues, are diagnosed and treated. It will be published in the Nov. 17 edition of the journal Circulation with an accompanying editorial.
"Obesity caused by chronic consumption of a high-calorie, high-fat diet is a worldwide epidemic, representing one of the greatest threats to global health," says principal investigator Vladimir Bogdanov, PhD, associate professor and director of the Hemostasis Research Program within the Division of Hematology Oncology at the UC College of Medicine and member of the Cincinnati Cancer Center and UC Cancer Institute. "White blood cells play a key role in fueling adipose tissue (fat) inflammation and insulin resistance in obesity and also promote the clogging of arteries, or atherosclerosis, setting the stage for heart attack and stroke. While these outcomes linked with a high fat diet and fat in the blood on white blood cells have been shown in animal models and humans, the impact of high fat diets on other bone marrow-derived cells, like red blood cells, is not well defined.
"Evidence is emerging that red blood cells play an important regulatory role in the development of atherosclerosis, binding pro-inflammatory proteins that cause dysfunction in the inner lining of the blood vessel wall--the endothelium. We explored how a high fat-diet causes red blood cell dysfunction in this study."
Bogdanov and his team fed a 60 percent high-fat diet to a group of animal models for 12 weeks and saw an increased amount of key proteins that stimulate white blood cells bound to red blood cells. These white blood cells, also known as macrophages, are a type of white blood cell that "eats" cellular debris, foreign substances, microbes, cancer cells and anything else that does not have the types of proteins specific to the surface of healthy body cells on its surface. They also play a crucial role in atherosclerosis.
"In red blood cells from animal models fed a high-fat diet, there was an increase in cholesterol found in the cell membrane and phosphatidylserine levels, promoting inflammatory reactions. Phosphatidylserine is a phospholipid membrane component which plays a key role in the cycle of cells," Bogdanov says. "When red blood cells from the animals being fed the high-fat diet were injected into a control group, eating a normal diet, there was a three-fold increase in their spleens' uptake of red blood cells. The spleen is involved in the removal of blood cells, as well as systemic inflammation.
"All of these findings show that the dysfunction of red blood cells, corresponding with dysfunction of the lining of blood vessels, occurs very early in diet-induced obesity and may play a part in the formation of atherosclerosis. Diets high in saturated fat have long been associated with endothelial dysfunction, the precursor to atherosclerosis, but to our knowledge, the effects of high-fat diet on red blood cells have not been rigorously examined."
He adds that in humans, high cholesterol is associated with alterations in red blood cells which are improved by treatment with statins, but the majority of obese humans do not have severe high cholesterol as was the case with the animal models in the study.
Friday, November 13, 2015
Healthy diet may reduce risk of ovarian cancer in African-American women
A healthy diet may reduce the risk of ovarian cancer in African-American women, according to data presented at the Eighth American Association for Cancer Research (AACR) Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held Nov. 13-16.
"Because there is currently no reliable screening available for ovarian cancer, most cases are diagnosed at advanced stages," said the study's author, Bo (Bonnie) Qin, PhD, a postdoctoral associate at Rutgers Cancer Institute of New Jersey. "That highlights a critical need for identifying modifiable lifestyle factors, including dietary interventions."
Ovarian cancer is the fifth leading cause of cancer death among women in the United States. African-American women are less likely than white women to be diagnosed with the disease, but more likely to die from it. In order to assess whether an improved diet could reduce the risk of ovarian cancer in African-American women, Qin analyzed the diets of 415 women with ovarian cancer and 629 control patients, using data from the African-American Cancer Epidemiology Study, a population-based case-control study of ovarian cancer in African-American women in 11 sites in the United States.
Qin; her mentor Elisa V. Bandera, MD, PhD, professor of epidemiology at Rutgers Cancer Institute of New Jersey; and fellow researchers evaluated the impact of three index-based dietary patterns: the 2005 Healthy Eating Index (HEI-2005), which was based on the federal Dietary Guidelines for Americans; the 2010 Healthy Eating Index (HEI-2010), which reflects the most recent dietary guidelines and has an increased emphasis on quality; and the Alternate Healthy Eating Index-2010 (AHEI-2010), which is based on a different nutrition guide, the Healthy Eating Pyramid.
Women answered questions about their diet in the year leading up to a diagnosis (for patients) or to the time of an interview (for controls). They received scores based on numerous components of the three diets.
Qin said that among all African-American women in the study, those with the highest adherence to an AHEI-2010 diet were 34 percent less likely to be diagnosed with ovarian cancer than women with the lowest AHEI-2010 adherence.
Among postmenopausal women, the women with the highest quartile of HEI-2010 scores were 43 percent less likely to be diagnosed with ovarian cancer, and the women with the highest quartile AHEI-2010 scores were 51 percent less likely to be diagnosed with ovarian cancer than the women in the lowest quartile.
Qin said the benefits of HEI-2010 come from higher intake of total vegetables, greens, beans, seafood, and plant proteins, combined with lower intake of empty calories, such as those from solid fats, alcohol, and added sugars. Similarly, the benefits of AHEI-2010 derive from higher vegetable intake and lower intake of sugar-sweetened beverages and fruit juice.
The diets have many common elements, but AHEI-2010 has more specific recommendations for protein and fat sources, including nuts, legumes, and omega-3 fatty acids EPA and DHA. HEI-2010 uses an energy density approach, which recommends optimal intake of nutrients relative to a person's daily diet.
Qin said further research is necessary to determine whether all aspects of the healthier diets contributed to reduced risk, or whether specific nutrients conferred the benefits.
"As a high quality diet is likely to have benefits for many chronic conditions, it is probably a safe bet for better health in general," she said.
Qin said the main limitation of this study is that it required women to recall their diet up to one year before the study, which introduces the possibility of recall bias and inaccurate reporting.
Thursday, November 12, 2015
Nut intake lowers the risk of cardiovascular disease
In a study published yesterday in the American Journal of Clinical Nutrition, researchers performed a systematic review and meta-analysis of controlled trials to investigate the effects of tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) on blood lipids, lipoproteins, blood pressure and inflammation in adults 18 years and older without prevalent cardiovascular disease (CVD). Tree nut consumption was shown to lower total cholesterol, triglycerides, LDL cholesterol and its primary apolipoprotein, ApoB.
Of the 1,301 potentially eligible studies, 61 crossover and parallel trials met eligibility criteria with a total of 2,582 individuals. Interventions ranged from 3-26 weeks (median 4 weeks). Nuts were provided in all of the trials, rather than relying only on dietary advice. The amount of nuts varied from 5 to 100 grams per day (median 56 grams/day or approximately 2 ounces). Compared with the control groups, consumption of tree nuts (per serving/day) significantly lowered total cholesterol (-4.7mg/dL; 95% CI-5.3,-4.0), LDL cholesterol, ApoB (-3.7mg/dL; 95% CI -5.2,-2.3) and triglycerides (-2.2mg/dL; 95% CI-3.8,-0.5).
"Accumulating evidence suggests that nut intake lowers the risk of cardiovascular disease. Our findings, showing that nut intake lowers LDL cholesterol, ApoB and triglycerides in clinical trials, provide mechanistic evidence to support this relationship," said lead author Liana Del Gobbo, PhD, currently a researcher in Cardiovascular Medicine at Stanford University. She conducted the study as a research fellow at the Friedman School of Nutrition Science and Policy at Tufts. Interestingly, stronger effects for ApoB were observed in populations with type-2 diabetes (-11.5mg/dL; 95% CI-16.2,-6.8) than among healthy populations (-2.5mg/dL; 95% CI-4.7,-0.3) (p-heterogeneity=0.015). According to the senior author, Dariush Mozaffarian, MD, DrPH, Dean of the Friedman School of Nutrition Science and Policy at Tufts University, "ApoB can provide even better information about risk of heart disease than LDL concentrations. Our new findings suggest that eating nuts may be especially important for lowering cardiovascular risk in the setting of diabetes or insulin resistance."
Nuts contain important nutrients such as unsaturated fats, high quality protein, vitamins (i.e., vitamin E, folate and niacin), minerals (i.e., magnesium, calcium and potassium) and phytochemicals--all of which may offer cardioprotective properties, prompting the U.S. Food and Drug Administration to announce a qualified health claim for nuts and heart disease in 2003. The claim states, "Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."
"This new analysis provides further support that nuts can and should be part of a heart-healthy diet," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "Just 1.5 ounces of nuts per day (about 1/3 cup) can provide many of the important vitamins, minerals and energy we need throughout the day."
Wednesday, November 11, 2015
Achieving Life's Simple 7 reduces more than heart disease
Achieving the seven heart-health metrics of the American Heart Association's Life's Simple 7 also helps reduce many other chronic diseases, according to a study presented at the American Heart Association's Scientific Sessions 2015.
Researchers analyzed the health information of 6,814 adults, who were followed for an average 10.2 years. Each component of the Life's Simple 7 metrics (smoking, body mass index, physical activity, diet, total cholesterol, blood pressure and blood glucose) was categorized into three levels: ideal, intermediate and poor. Rates of non-cardiovascular diseases overall were lower with improving Life's Simple 7 health status. They also found compared to those in the poor category, people in the ideal category of the Life's Simple 7 score had a:
- 20 percent lower risk for cancer;
- 62 percent lower risk for chronic kidney disease;
- 43 percent lower risk for pneumonia; and
- 49 percent lower risk for chronic obstructive pulmonary disease (COPD).
Tuesday, November 10, 2015
Stress can cause fever
Psychogenic fever is a stress-related,
psychosomatic condition that manifests itself in a high body
temperature. It is caused by exposure to emotional events or to chronic
stress. Dr. Takakazu Oka, of the Kyushu University Graduate School of
Medical Sciences, specializes in psychosomatic medicine and treats
patients with psychogenic fevers. In his review article "Psychogenic fever: how psychological stress affects body temperature in the clinical population," published in the journal Temperature, Dr. Oka introduces his recent findings from his research and clinical experience regarding the disease.
"While this condition is known in the literature, only a few doctors
in the world study it and treat patients with psychogenic fevers," says
Professor Andrej Romanovsky, of St. Joseph's Hospital and Medical Center
in Arizona, and the Editor-in-Chief of Temperature, "this is why we have invited Dr. Oka to share his unique experience."
According to Dr. Oka, there has been no epidemiological study of psychogenic fevers yet. Therefore, the number of affected patients is unknown. However, Dr. Oka relays that this condition is relatively widespread -- based on the available case reports and his own clinical practice. He has seen a high number of patients, especially amongst Japanese students due to academic stress. Dr. Oka explains that due to many doctors not fully understanding how stress can affect body temperature, patients with psychogenic fever are being diagnosed with cause unknown for their disabling symptoms.
Dr. Oka further describes that the complaints from patients are of the fever itself, along with the symptoms from the high temperature, symptoms from the stress, plus the symptoms from the psychiatric diseases that the patient may suffer from. "High body temperature is just one of the symptoms induced or exacerbated by stress," Dr. Oka says, "Patients ask for the treatment of fever not just their temperature be normalized, but all symptoms to be treated."
Several treatment options are currently available, but, in general, they are similar to the treatments of other stress-related diseases and not specific to psychogenic fever. However, Dr. Oka is convinced that a breakthrough in treatment will occur in the near future, as more research is conducted. He explains, "Because even their doctors did not believe the fever is caused by or related with psychological stress… Recent animal studies enable the doctors to be aware of this pathophysiology."
Instead of using the traditional term "psychogenic fever," Dr. Oka proposes to call this condition "functional hyperthermia." Using the word "functional" would prevent stigmatizing these patients, and in a clinical setting connotes both stress-related pathology and impaired functioning of the autonomic nervous system which is important to convey in treatment of the condition.
According to Dr. Oka, there has been no epidemiological study of psychogenic fevers yet. Therefore, the number of affected patients is unknown. However, Dr. Oka relays that this condition is relatively widespread -- based on the available case reports and his own clinical practice. He has seen a high number of patients, especially amongst Japanese students due to academic stress. Dr. Oka explains that due to many doctors not fully understanding how stress can affect body temperature, patients with psychogenic fever are being diagnosed with cause unknown for their disabling symptoms.
Dr. Oka further describes that the complaints from patients are of the fever itself, along with the symptoms from the high temperature, symptoms from the stress, plus the symptoms from the psychiatric diseases that the patient may suffer from. "High body temperature is just one of the symptoms induced or exacerbated by stress," Dr. Oka says, "Patients ask for the treatment of fever not just their temperature be normalized, but all symptoms to be treated."
Several treatment options are currently available, but, in general, they are similar to the treatments of other stress-related diseases and not specific to psychogenic fever. However, Dr. Oka is convinced that a breakthrough in treatment will occur in the near future, as more research is conducted. He explains, "Because even their doctors did not believe the fever is caused by or related with psychological stress… Recent animal studies enable the doctors to be aware of this pathophysiology."
Instead of using the traditional term "psychogenic fever," Dr. Oka proposes to call this condition "functional hyperthermia." Using the word "functional" would prevent stigmatizing these patients, and in a clinical setting connotes both stress-related pathology and impaired functioning of the autonomic nervous system which is important to convey in treatment of the condition.
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Diet developed for reducing cholesterol also lowers blood pressure
A diet developed for reducing cholesterol also lowers blood pressure, a St. Michael's Hospital study has found.
The research, published today in Nutrition, Metabolism and Cardiovascular Disease, was a secondary analysis of data collected for a 2011 study on the effect of the 'portfolio diet' on cholesterol.
The portfolio diet lowered blood pressure by an average two per cent, when compared with another diet recommended to reduce hypertension.
The portfolio diet includes foods that are scientifically-proven to lower cholesterol including mixed nuts, soy protein, plant sterols (found in vegetable oils and leafy vegetables) and viscous fiber (found in oats, barley and eggplant). The comparison method, a dietary approach to stopping hypertension, or DASH diet, emphasizes fruit, vegetables and whole grains, reduced meat and dairy intake, and eliminating snack food.
"This is a very important secondary finding to the original study, adding to the literature connecting diet with health," said Dr. David Jenkins, the study's lead author, director of the Risk Factor Modification Centre at St. Michael's and professor of nutritional sciences and medicine at the University of Toronto. "It fills in yet another area we often worry about. We can now say the dietary portfolio is ideal for reducing overall risk of cardiovascular disease."
The modest, two per cent reduction in blood pressure on the portfolio diet is in addition to the five to ten millimeter blood pressure improvement associated with a DASH-type diet. Although the DASH diet had higher compliance rates, the portfolio diet was more effective in reducing blood pressure.
High blood pressure and cholesterol are major risk factors for cardiovascular disease and stroke, historically treated with medications. However, Dr. Jenkins' research and work focuses on dietary and lifestyle changes to reduce risk factors.
"Dietary approaches have been found to be as effective as the starting dose of the average single blood pressure medication," said Dr. Jenkins. "Overall, research has shown that plant-based diets emphasizing foods higher in protein, oil and fiber reduce the risk of cardiovascular disease and stroke."
Previous research and studies have found that individual components of the dietary portfolio (mixed nuts, soy protein and viscous fiber) are effective at reducing blood pressure.
Dr. Jenkins said the diet's positive effect on cholesterol has already impacted guidelines in Canada and Europe.
The portfolio diet lowered blood pressure by an average two per cent, when compared with another diet recommended to reduce hypertension.
The portfolio diet includes foods that are scientifically-proven to lower cholesterol including mixed nuts, soy protein, plant sterols (found in vegetable oils and leafy vegetables) and viscous fiber (found in oats, barley and eggplant). The comparison method, a dietary approach to stopping hypertension, or DASH diet, emphasizes fruit, vegetables and whole grains, reduced meat and dairy intake, and eliminating snack food.
"This is a very important secondary finding to the original study, adding to the literature connecting diet with health," said Dr. David Jenkins, the study's lead author, director of the Risk Factor Modification Centre at St. Michael's and professor of nutritional sciences and medicine at the University of Toronto. "It fills in yet another area we often worry about. We can now say the dietary portfolio is ideal for reducing overall risk of cardiovascular disease."
The modest, two per cent reduction in blood pressure on the portfolio diet is in addition to the five to ten millimeter blood pressure improvement associated with a DASH-type diet. Although the DASH diet had higher compliance rates, the portfolio diet was more effective in reducing blood pressure.
High blood pressure and cholesterol are major risk factors for cardiovascular disease and stroke, historically treated with medications. However, Dr. Jenkins' research and work focuses on dietary and lifestyle changes to reduce risk factors.
"Dietary approaches have been found to be as effective as the starting dose of the average single blood pressure medication," said Dr. Jenkins. "Overall, research has shown that plant-based diets emphasizing foods higher in protein, oil and fiber reduce the risk of cardiovascular disease and stroke."
Previous research and studies have found that individual components of the dietary portfolio (mixed nuts, soy protein and viscous fiber) are effective at reducing blood pressure.
Dr. Jenkins said the diet's positive effect on cholesterol has already impacted guidelines in Canada and Europe.
Diet may determine your risk for rheumatoid arthritis
Two studies, presented this week at the
American College of Rheumatology Annual Meeting in San Francisco, show a
person's diet can significantly affect his or her chance of developing
rheumatoid arthritis.
Rheumatoid arthritis is the most common chronic autoimmune disease
that affects the joints. RA has the potential for joint damage and
deformity, with loss of function. The cause of RA is unknown. It affects
people of all ages, and women more commonly than men. RA causes pain,
stiffness and swelling, generally in multiple joints. RA may affect any
joint, but the small joints in the hands and feet are most frequently
involved. Rheumatoid inflammation may also develop in other organs such
as the lungs.
The first study found that typical Western diets high in red meat, processed meat, refined grains, fried food, high-fat dairy, and sweets can increase a person's risk of developing RA in comparison to Prudent diets made mostly of fruit, vegetables, legumes, whole grains, poultry and fish.
"The evidence for diet having a role in the etiology of RA is inconsistent, sometimes conflicting. The prior studies based on individual nutrients and food groups may not have enough power to detect small effects," explains lead investigator in the study, Bing Lu, MD, DrPH; assistant professor of medicine; Brigham and Women's Hospital and Harvard Medical School.
"Instead, overall dietary pattern analysis examines the cumulative effects of multiple nutrients and foods, and may be more predictive of disease risk than individual foods or nutrients. The single-nutrient approach may be inadequate for taking into account complicated interactions among nutrients, and high levels of inter-correlation makes it difficult to examine their separate effects. Therefore, we proposed a prospective study examining the overall effect of dietary patterns to furnish novel information about diet and etiology of RA."
Through the Nurses' Health Study II, -- a study of 116,460 female registered nurses ranging in age from 25 to 42 -- Dr. Lu's team followed 93,859 women without RA who filled out dietary questionnaires every four years between 1991 and 2011. From these questionnaires, the researchers discovered two dietary patterns among the women: Western and Prudent.
Throughout the course of the study, 347 women developed RA at an average age of 49. After taking into consideration their age, smoking status, body mass index, total calories consumed each day, alcohol consumption, level of physical activity, and socioeconomic factors, the women on Prudent diets had less of a chance of developing RA, while those on the Western diet were at increased risk, but BMI weakened these findings.
"This indicates that the effects of the two dietary patterns on RA risk may be partially through BMI, and the clear mechanism is still unknown. Therefore, adherence to a healthy diet may be a way to prevent this debilitating disease, especially for high risk population," explains Dr. Lu of the findings.
The second study, showed that following the Dietary Guidelines for Americans can also lower one's chances of developing the disease. According to the United States Department of Agriculture, "the Dietary Guidelines for Americans … provide authoritative advice about consuming fewer calories, making informed food choices, and being physically active to attain and maintain a healthy weight, reduce risk of chronic disease, and promote overall health."
Little has been reported on how following these guidelines can impact one's risk of developing RA, so Dr. Lu's team again utilized the Nurses' Health Study II and food frequency questionnaires to determine if following these guidelines could lessen one's chance of developing RA.
In this study -- based on dietary intakes of various foods provided in the food frequency questionnaires, -- the Alternate Healthy Eating Index 2010 was created to measure how well the participants followed the Dietary Guidelines for Americans (2010), and the researchers observed associations of the diets of study participants and the likelihood of developing RA.
Looking at data from 1991 to 2011, 347 study participants self-reported a diagnosis of RA, which was later confirmed through their medical records. The researchers noted those who best adhered to the Dietary Guidelines for Americans (based on the Alternate Healthy Eating Index 2010) had a 33 percent reduced risk of developing RA when compared to those who did not follow the guidelines as closely. And, just as in the first study, the researchers noted that body mass index may be a modest intermediate factor linking diet and risk of RA.
Of those who developed RA, 215 had seropositive RA (diagnosed due to the presence of anti-cyclic citrullinated peptides or rheumatoid factor in blood work) and 132 had seronegative RA (an RA diagnosis, but one that is lacking definitive bloodwork). This led the researchers to further look into the difference between these two groups, and they found the association between following the dietary guidelines and the risk of developing RA was stronger among those with seronegative RA than those with seropositive.
"As we found with the first study, it is clear that a healthy diet may prevent RA development, and our team is interested in conducting further studies to look at why diet is associated with this risk," Dr. Lu concludes.
The first study found that typical Western diets high in red meat, processed meat, refined grains, fried food, high-fat dairy, and sweets can increase a person's risk of developing RA in comparison to Prudent diets made mostly of fruit, vegetables, legumes, whole grains, poultry and fish.
"The evidence for diet having a role in the etiology of RA is inconsistent, sometimes conflicting. The prior studies based on individual nutrients and food groups may not have enough power to detect small effects," explains lead investigator in the study, Bing Lu, MD, DrPH; assistant professor of medicine; Brigham and Women's Hospital and Harvard Medical School.
"Instead, overall dietary pattern analysis examines the cumulative effects of multiple nutrients and foods, and may be more predictive of disease risk than individual foods or nutrients. The single-nutrient approach may be inadequate for taking into account complicated interactions among nutrients, and high levels of inter-correlation makes it difficult to examine their separate effects. Therefore, we proposed a prospective study examining the overall effect of dietary patterns to furnish novel information about diet and etiology of RA."
Through the Nurses' Health Study II, -- a study of 116,460 female registered nurses ranging in age from 25 to 42 -- Dr. Lu's team followed 93,859 women without RA who filled out dietary questionnaires every four years between 1991 and 2011. From these questionnaires, the researchers discovered two dietary patterns among the women: Western and Prudent.
Throughout the course of the study, 347 women developed RA at an average age of 49. After taking into consideration their age, smoking status, body mass index, total calories consumed each day, alcohol consumption, level of physical activity, and socioeconomic factors, the women on Prudent diets had less of a chance of developing RA, while those on the Western diet were at increased risk, but BMI weakened these findings.
"This indicates that the effects of the two dietary patterns on RA risk may be partially through BMI, and the clear mechanism is still unknown. Therefore, adherence to a healthy diet may be a way to prevent this debilitating disease, especially for high risk population," explains Dr. Lu of the findings.
The second study, showed that following the Dietary Guidelines for Americans can also lower one's chances of developing the disease. According to the United States Department of Agriculture, "the Dietary Guidelines for Americans … provide authoritative advice about consuming fewer calories, making informed food choices, and being physically active to attain and maintain a healthy weight, reduce risk of chronic disease, and promote overall health."
Little has been reported on how following these guidelines can impact one's risk of developing RA, so Dr. Lu's team again utilized the Nurses' Health Study II and food frequency questionnaires to determine if following these guidelines could lessen one's chance of developing RA.
In this study -- based on dietary intakes of various foods provided in the food frequency questionnaires, -- the Alternate Healthy Eating Index 2010 was created to measure how well the participants followed the Dietary Guidelines for Americans (2010), and the researchers observed associations of the diets of study participants and the likelihood of developing RA.
Looking at data from 1991 to 2011, 347 study participants self-reported a diagnosis of RA, which was later confirmed through their medical records. The researchers noted those who best adhered to the Dietary Guidelines for Americans (based on the Alternate Healthy Eating Index 2010) had a 33 percent reduced risk of developing RA when compared to those who did not follow the guidelines as closely. And, just as in the first study, the researchers noted that body mass index may be a modest intermediate factor linking diet and risk of RA.
Of those who developed RA, 215 had seropositive RA (diagnosed due to the presence of anti-cyclic citrullinated peptides or rheumatoid factor in blood work) and 132 had seronegative RA (an RA diagnosis, but one that is lacking definitive bloodwork). This led the researchers to further look into the difference between these two groups, and they found the association between following the dietary guidelines and the risk of developing RA was stronger among those with seronegative RA than those with seropositive.
"As we found with the first study, it is clear that a healthy diet may prevent RA development, and our team is interested in conducting further studies to look at why diet is associated with this risk," Dr. Lu concludes.
Monday, November 9, 2015
Being thin and carrying fat around the midsection more deadly than being obese
Abstract: http://www.annals.org/article.aspx?doi=10.7326/M14-2525
Editorial: http://www.annals.org/article.aspx?doi=10.7326/M15-2435
Normal-weight people who carry fat around their midsections have a greater mortality risk than those who are overweight or obese but have normal fat distribution, according to an article published in Annals of Internal Medicine.
Studies have shown that central obesity is associated with increased total and cardiovascular mortality. However, no studies have specifically focused on assessing the mortality risk in persons with normal body mass index (BMI) and central obesity compared with those who are overweight or obese according to BMI. Researchers examined data from a large cohort of Third National Health and Nutrition Examination Survey (NHANES III) participants to compare the total and cardiovascular mortality risks for persons with different combinations of body mass index (BMI) and waist-to-hip ratios (WHR). They found that normal-weight adults with central obesity have the worst long-term survival compared with any group, regardless of BMI. The data showed that a normal-weight person with central obesity had twice the mortality risk of participants who were overweight or obese according to BMI only.
The researchers conclude that persons with normal-weight central obesity may represent an important target population for lifestyle modification and other preventive strategies.
Researchers find link between specific vitamin D levels and heart problems
A lack of vitamin D can result in weak bones. Recent studies also show that vitamin D deficiency is linked to more serious health risks such as coronary artery disease, heart attacks, and strokes.
And now, a new study shows what level of deficiency puts someone at risk of developing these heart problems.
Researchers at the Intermountain Medical Center Heart Institute in Salt Lake City have found that patients are fine from a heart standpoint, and may need no further treatment, if their vitamin D level is anywhere above 15 nanograms per milliliter.
"Although vitamin D levels above 30 were traditionally considered to be normal, more recently, some researchers have proposed that anything above 15 was a safe level. But the numbers hadn't been backed up with research until now," said J. Brent Muhlestein, MD, co-director of cardiovascular research at the Intermountain Medical Center Heart Institute, and lead researcher of the study.
"Even if any level above 15 is safe, one out of 10 people still have vitamin D levels lower than that. This equates to a very large percentage of our population. The best way to determine one's vitamin D level is by getting a blood test," he said.
Dr. Muhlestein and his team will present their findings from the study at the 2015 American Heart Association Scientific Session in Orlando on Monday, Nov. 9, at 2 p.m., EST.
The body naturally produces vitamin D as a result of exposure to the sun, and it's also found in a few foods -- including fish, fish liver oils, and egg yolks as well as some dairy and grain products.
Those who don't have enough exposure to sunlight or vitamin D producing foods often have low vitamin D levels. Low levels are also attributed to race because people with dark skin have a natural protectant against ultraviolet light.
Dr. Muhlestein and his team have studied the effects of vitamin D on the heart for several years, looking at smaller numbers of patients. In this study, thanks to Intermountain Healthcare's vast clinical database, they were able to evaluate the impact of vitamin D levels on more than 230,000 patients.
The 230,000 patients were split up into four groups (<15 15-29="" 30-44="" adverse="" and="" artery="" attacks="" br="" by="" cardiac="" coronary="" death="" disease="" events="" failure.="" followed="" for="" heart="" incidents="" including="" kidney="" looked="" major="" ml="" next="" ng="" of="" or="" researchers="" stroke="" the="" three="" were="" who="" years="">
Dr. Muhlestein found that for the nine percent of patients in the greater than 15 group, their risk of cardiovascular events increased by 35 percent compared to the other three groups, and the risks faced by the other three groups weren't very different from each other.
"This study sheds new light and direction on which patients might best benefit from taking vitamin D supplements," said Dr. Muhlestein. "Even though there's a possibility that patients may benefit in some way from achieving higher blood levels of vitamin D, this new information tells us the greatest benefit to the heart will likely occur among patients whose vitamin D level is below 15 ng/ml."
Going forward, Dr. Muhlestein hopes to take these findings and perform a randomized trial with patients whose levels are below 15. The idea is to randomly separate them into groups and provide supplements for one but not the other to see what the long-term benefits for combatting heart problems really are.
"As we continue to study vitamin D and the heart, we hope to ultimately gain enough information so we can inform all patients specifically what they should do to reduce their cardiac risk as much as possible," he said15>
How low to go for blood pressure? Lower target could affect millions of Americans
A new study finds that at least 16.8 million Americans could potentially benefit from lowering their systolic blood pressure (SBP) to 120 mmHg, much lower than current guidelines of 140 or 150 mmHg. The collaborative investigation between the University of Utah, University of Alabama at Birmingham, and Columbia University, will be published Nov. 9 online in the Journal of the American College of Cardiology (JACC).
The scientists calculated the potential impact of preliminary results from the Systolic Blood Pressure Intervention Trial (SPRINT) that will be presented in full at the American Heart Association meeting and published online in the New England Journal of Medicine, also on Nov. 9. The initial analysis of SPRINT, reported in Sept., 2015, showed that using antihypertensive medications to reach a lower SBP target of 120 mmHg could greatly reduce risk for heart failure, heart attack, and death, compared to a target of 140 mmHg (SBP is the top number in a blood pressure reading). It's estimated that one in three U.S. adults have high blood pressure, or hypertension, a significant health concern.
"SPRINT could have broad implications," says lead author Adam Bress, Pharm.D., M.S., assistant professor of pharmacotherapy at the University of Utah College of Pharmacy. "Millions of Americans whose blood pressure is under control according to current guidelines may be considered uncontrolled if new guidelines adopt the intensive target of less than 120 mmHg studied in SPRINT."
While new medical guidelines for treating hypertension could be months to years away, this research finds that more than 16.8 million Americans, 7.6 percent of the population, could be recommended for intensive blood pressure management if guidelines incorporate a new, lower, SBP target based on SPRINT results. The number represents Americans who meet the same criteria as SPRINT participants: they are age 50 or older, have an SBP between 130-180 mmHg, are at high risk for cardiovascular disease, and do not have diabetes or a history of stroke, among other inclusion and exclusion criteria.
The current study also reports that new guidelines may affect some segments of the population more than others. Compared to Caucasians, African Americans and Hispanics were less likely to meet SPRINT eligibility criteria (9 percent vs. 4.8 percent, 4.3 percent). The differences are largely due to the fact that these minority populations have a higher prevalence of diabetes and other health conditions that could preclude them from being SPRINT eligible. Men were also more likely to be eligible for SPRINT than women (8.8 percent vs. 6.5 percent), in part because unlike men, women tend not to show increased risk for cardiovascular disease until they are over 65.
However in practice, it's common for physicians to prescribe treatments to patients who may have not been eligible for a clinical trial that demonstrated the efficacy and safety of a particular treatment. For example, some physicians may deviate from SPRINT eligibility by aggressively treating the blood pressure of any adult over 50, even if they do not have a high risk of cardiovascular disease. "Physicians are going to need to decide how far outside the SPRINT inclusion criteria to go," says co-author Rachel Hess, M.D., M.S., also a professor of internal medicine and population health sciences at the University of Utah School of Medicine. "It's going to be a tough decision."
The numbers of Americans meeting each sequential SPRINT eligibility requirement are:
- 219 million adults
- 95.1 million age 50 or older
- 37.3 million with elevated blood pressure (?130 mmHg)
- 26.4 million at high risk for cardiovascular disease
- 16.8 million with no diabetes, history of stroke, or other SPRINT exclusion criteria
Potential impacts of SPRINT results on the U.S. population were based on analyzing data from the 16,260 participants in the National Health and Nutrition Examination Survey (NHANES) between 2007 -- 2012 who met certain SPRINT inclusion and exclusion criteria. NHANES includes a representative cross-section of the American population, allowing for projection of these findings to the overall population. Most, but not all, SPRINT inclusion and exclusion criteria were accounted for in NHANES. For example information on subclinical cardiovascular disease and a history of medical non-adherence are not represented in the national survey.
New blood pressure guidelines will have to weight potential adverse effects that could overshadow its benefits, and whether increasing blood pressure medications over the course of multiple years is cost-effective. But the numbers obtained in this study offer a glimpse into the potentially wide ranging impact of changing blood pressure guidelines.
"Given that millions of U.S. adults meet SPRINT eligibility criteria, the implementation of SPRINT recommendations could have a profound impact on how blood pressure is treated in this country," says senior author Paul Muntner, Ph.D., a professor of epidemiology at the University of Alabama. "Even more important, is its potential for greatly reducing the incidence of cardiovascular disease."
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