Study challenges concept of 'healthy' obesity

Obese individuals who have no signs of cardiovascular disease show a much higher prevalence of early plaque buildup in the arteries compared to healthy normal weight individuals, according to a study published today in the Journal of the American College of Cardiology. The study challenges the idea of "healthy" obesity, and researchers recommend all obese individuals be counseled about their risks for cardiovascular disease and receive tips for achieving a healthy weight.

Obesity can often lead to cardiovascular disease through the development of dyslipidemia (abnormal amounts of fat or cholesterol in the blood), hyperglycemia (high blood sugar) and hypertension (high blood pressure)—all common conditions in obese individuals. But, the idea of "healthy" obese, individuals whose body weight puts them in the obese category but they show no signs of cardiovascular disease, is controversial.

Researchers in this study looked at 14, 828 metabolically healthy Korean adults aged 30 to 59 years who had no known cardiovascular disease and had undergone a health checkup including cardiac tomography estimation of coronary artery calcium scores, which is a measure of calcium build up in the plaque on artery walls. CAC scoring can determine early stage heart disease, such as atherosclerosis, before symptoms are present. Obesity or normal weight was determined using a standard Asian body mass index scale.

Based on CAC scores, obese individuals were found to have a much higher prevalence of subclinical coronary atherosclerosis, or early-stage plaque buildup in the arteries, than their normal weight counterparts. Atherosclerosis, if not managed, can lead to heart attack and sudden cardiac death, among other cardiovascular conditions.

"Obese individuals who are considered 'healthy' because they don't currently have heart disease risk factors, should not be assumed healthy by their doctors," said Yoosoo Chang, MD, lead author of the study and professor at Kangbuk Samsung Hospital Total Healthcare Center Center for Cohort Studies in Seoul, Korea. "Our research shows that the presence of obesity is enough to increase a person's risk of future heart disease and that the disease may already be starting to form in their body. It's important that these people learn this while they still have time to change their diet and exercise habits to prevent a future cardiovascular event."

Light physical activity every day can help avoid developing disabilities

Pushing a shopping cart or a vacuum doesn’t take a lot of effort, but enough of this sort of light physical activity every day can help people with or at risk of knee arthritis avoid developing disabilities as they age, according to a new Northwestern Medicine® study.

It is known that the more time people spend in moderate or vigorous activities, the less likely they are to develop disability, but this is the first study to show that spending more time in light activities can help prevent disability, too.

“Our findings provide encouragement for adults who may not be candidates to increase physical activity intensity due to health limitations,” said Dorothy Dunlop, professor of medicine at Northwestern University Feinberg School of Medicine and lead author of the study. “Even among those who did almost no moderate activity, the more light activity they did, the less likely they were to develop disability.”

Results of the study were published April 29, 2014 in the British Medical Journal.

The scientists identified a group of almost 1,700 adults, ages 45 to 79, from the Osteoarthritis Initiative study who were free of disability but were at elevated risk for developing it because they had knee osteoarthritis or other risk factors for knee osteoarthritis, such as obesity.

Knee osteoarthritis commonly leads to disability, preventing people from engaging in activities essential to independent living and quality of life, such as dressing, bathing, walking across a room or making telephone calls, managing money and grocery shopping. Two-thirds of obese adults are expected to develop knee osteoarthritis during their lifetime.

To track the amount and intensity of physical activity these at-risk people engaged in every day, scientists had them wear an accelerometer during waking hours for about a week. The device is worn around the hip and measures the intensity of movement. The data collected reveals how much time is spent in vigorous, moderate or light activities.

Two years after collecting the results from the accelerometer, participants were surveyed and asked about the development of disabilities. As expected, more time spent in moderate or vigorous activity was associated with lower reports of disabilities, but researchers were pleased to find that greater time spent in light intensity activities also was related to fewer disabilities, even after accounting for time spent in moderate activities.

Those who spent more than four hours per day doing light physical activity had more than a 30 percent reduction in the risk for developing disability compared to those spending only three hours a day in light activity (the least average number of hours collected in the study).

The findings controlled for time spent in moderate or vigorous physical activity and other predictors of disability, both demographic and health factors.

“We were delighted to see that more time spent during the day, simply moving your body, even at a light intensity, may reduce disability,” Dunlop said. “Now people with health problems or physical limitations, who cannot increase the intensity of their activity, have a starting place in the effort to stay independent.”

Vitamin D deficiency linked to aggressive prostate cancer

African-American and European-American men at high risk of prostate cancer have greater odds of being diagnosed with an aggressive form of the disease if they have a vitamin D deficiency, according to a new study from Northwestern Medicine® and the University of Illinois at Chicago (UIC).

Results of the study were published May 1, 2014 in Clinical Cancer Research, a journal of the American Association for Cancer Research.

"Vitamin D deficiency could be a biomarker of advanced prostate tumor progression in large segments of the general population," said Adam B. Murphy, M.D., lead author of the study. "More research is needed, but it would be wise for men to be screened for vitamin D deficiency and treated."

Murphy is an assistant professor in urology at Northwestern University Feinberg School of Medicine, a physician at Jesse Brown VA Medical Center and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

"This is the first study to look at vitamin D deficiency and biopsy outcomes in men at high risk of prostate cancer," said Rick Kittles, senior author of the study. "Previous studies focused on vitamin D levels in men either with or without prostate cancer."

Kittles is an associate professor in the department of medicine at UIC.

Scientists examined data collected from a diverse group of more than 600 men from the Chicago area who had elevated PSA levels or other risk factors for prostate cancer. Each man was screened for vitamin D deficiency before undergoing a prostate biopsy.

The authors were surprised to find that vitamin D deficiency seemed to be a predictor of aggressive forms of prostate cancer diagnosis in African-American and European-American men, even after adjusting for potential confounders including diet, smoking habits, obesity, family history and calcium intake.

"These men, with severe vitamin D deficiency, had greater odds of advanced grade and advanced stage of tumors within or outside the prostate," Murphy said.

European-American men and African-American men had 3.66 times and 4.89 times increased odds of having aggressive prostate cancer respectively and 2.42 times and 4.22 times increased odds of having tumor stage T2b or higher, respectively.

African-American men with severe vitamin D deficiency also had 2.43 times increased odds of being diagnosed with prostate cancer.

"Vitamin D deficiency is more common and severe in people with darker skin and it could be that this deficiency is a contributor to prostate cancer progression among African-Americans," Murphy said. "Our findings imply that vitamin D deficiency is a bigger contributor to African-American prostate cancer."

Unless it is severe, vitamin D deficiency is fairly asymptomatic, so more effort needs to be put on screening, Murphy said.

"It is a good idea to get your levels checked on a yearly basis," Murphy said. "If you are deficient, you and you doctor can make a plan on how to reverse it through diet, supplements or other therapies."

Extreme sleep durations may affect brain health in later life

A new research study led by Brigham and Women's Hospital (BWH) published in The Journal of the American Geriatrics Society in May, shows an association between midlife and later life sleeping habits with memory; and links extreme sleep durations to worse memory in later life. The study suggests that extreme changes in sleep duration from middle age to older age may also worsen memory function.

"Sleep Duration In Midlife and Later Life In Relation to Cognition: The Nurses' Health Study," led by Elizabeth Devore, ScD, instructor in medicine in the Channing Division of Network Medicine at BWH found that women who slept five or fewer hours, or nine or more hours per day, either in midlife or later life, had worse memory, equivalent to nearly two additional years of age, than those sleeping seven hours per day. Women whose sleep duration changed by greater than two hours per day over time had worse memory than women with no change in sleep duration.

This study was the first to evaluate associations of sleep duration at midlife and later life, and change in sleep duration over time, with memory in 15,263 participants of the Nurses' Health Study. Participants were female nurses, aged 70 or older and were free of stroke and depression at the initial cognitive assessment.

"Given the importance of preserving memory into later life, it is critical to identify modifiable factors, such as sleeping habits, that may help achieve this goal," Devore stated. "Our findings suggest that getting an 'average' amount of sleep, seven hours per day, may help maintain memory in later life and that clinical interventions based on sleep therapy should be examined for the prevention of cognitive impairment."

Specifically, researchers report that:

- Extreme sleep durations may adversely affect memory at older ages, regardless of whether they occur at mid-life or later-life.
- Greater changes in sleep duration appear to negatively influence memory in older adults.
- Women with sleep durations that changed by two or more hours per day from midlife to later life performed worse on memory tests than women with no change in sleep duration, equivalent to being one to two years older in age, compared to those whose sleep duration did not change during that time period.

"These findings add to our knowledge about how sleep impacts memory," said Devore. "More research is needed to confirm these findings and explore possible mechanisms underlying these associations."

Combination of statin and omega-3 fatty acid may provide cardioprotective effects

New findings from an in vitro study, led by researchers at Brigham and Women's Hospital (BWH), show that the combination of statins and eicosapentaenoic acid (EPA), an omega-3 fatty acid, may potentially reduce cardiovascular risk. This research was presented May 1 at a peer-reviewed poster session at the National Lipid Association Scientific Sessions in Orlando, Florida.

"We know that endothelial cell dysfunction is emerging as an early and important predictor of cardiovascular disease and plays an essential role in plaque development. Treatments that provide beneficial effects on endothelial function could have very important implications for a patient population at high risk for heart disease," said R. Preston Mason, PhD, of BWH's Department of Medicine and lead author of the study. "We found that a combination of statins and EPA omega-3 fatty acid, or fish oil, had beneficial effects on endothelial cells and function."

Using human tissue, researchers analyzed whether EPA could enhance the benefits of statins on endothelial cells. Blood vessels from human umbilical vein cells were collected from healthy donors and then subjected to disease-like conditions in the laboratory using oxidized low-density lipoproteins (LDL). Using nanotechnology approaches, researchers measured the release of molecules from the endothelial cells including nitric oxide, an essential regulator of blood vessel health. The researchers found that the combination of EPA and a statin was more than 50 percent better than the statin alone in reversing endothelial damage.

Researchers conclude that there is a potent and favorable interaction between the omega-3 fatty acid, EPA, and widely used statins, and suggest that a therapeutic strategy with this combination may be beneficial patients with increased risk for CV disease.

These new results may also underscore the importance of coupling high-quality statin therapies with an omega-3 agent such as EPA in potentially reducing cardiovascular risk, in addition to treating elevated triglycerides. High circulating triglyceride levels are considered a risk factor associated with cardiovascular disease, along with HDL, LDL cholesterol and blood pressure. New strategies to help patients manage this aspect of cardiovascular risk show promise in the overall prevention and treatment of heart disease.

The researchers note that future research is needed, particularly in humans, including cardiovascular outcomes data in randomized clinical trials.

Eskimos have coronary artery disease at the same rate as other populations

Oily fish are currently recommended as part of a heart healthy diet. This guideline is partially based on the landmark 1970s study from Bang and Dyerberg that connected the low incidence of coronary artery disease (CAD) among the Eskimos of Greenland to their diet, rich in whale and seal blubber. Now, researchers have found that Eskimos actually suffered from CAD at the same rate as their Caucasian counterparts, meaning there is insufficient evidence to back Bang and Dyerberg's claims. Their findings are published in the Canadian Journal of Cardiology.

Using 40 years of new information and research, a team of investigators set out to reexamine Bang and Dyerberg's study of Greenland Eskimos and CAD. This study is still widely cited today when recommending the dietary addition of fish oil supplements (like omega-3 fatty acids) or oily fish to help avoid cardiovascular problems. However, the new review of information has determined that Bang and Dyerberg failed to actually investigate the cardiovascular health of the Eskimo population, meaning that the cardioprotective effects of their diet are unsubstantiated.

"Bang and Dyerberg's seminal studies from the 1970s are routinely invoked as 'proof' of low prevalence of CAD in Greenland Eskimos ignoring the fact that these two Danish investigators did not study the prevalence of CAD," notes lead investigator George Fodor, MD, PhD, FRCPC, FAHA. "Instead, their research focused on the dietary habits of Eskimos and offered only speculation that the high intake of marine fats exerted a protective effect on coronary arteries."

Bang and Dyerberg relied mainly on annual reports produced by the Chief Medical Officer of Greenland to ascertain CAD deaths in the region. The 2014 study has identified a number of reasons that those records were likely insufficient, mainly that the rural and inaccessible nature of Greenland made it difficult for accurate records to be kept and that many people had inadequate access to medical personnel to report cardiovascular problems or heart attacks. In fact, researchers have now found that concerns about the validity of Greenland's death certificates have been raised by a number of different reports and that at the time, more than 30% of the population lived in remote outposts where no medical officer was stationed. This meant that 20% of the death certificates were completed without a doctor having examined the body.

The data collected through this new investigation shows that Eskimos do have a similar prevalence of CAD to non-Eskimo populations, and in fact, they have very high rates of mortality due to cerebrovascular events (strokes). Overall, their life expectancy is approximately 10 years less than the typical Danish population and their overall mortality is twice as high as that of non-Eskimo populations.

"Considering the dismal health status of Eskimos, it is remarkable that instead of labeling their diet as dangerous to health, a hypothesis has been construed that dietary intake of marine fats prevents CAD and reduces atherosclerotic burden," remarks Dr. Fodor.

Many recent large and well-designed studies have shown ambiguous or negative results regarding the cardioprotective properties of omega-3 fatty acids and fish oil supplements, and yet partly based on the work of Bang and Dyerberg, they are still widely recommended as part of a heart healthy diet plan.

"Publications still referring to Bang and Dyerberg's nutritional studies as proof that Eskimos have low prevalence of CAD represent either misinterpretation of the original findings or an example of confirmation bias," concludes Dr. Fodor. "To date, more than 5000 papers have been published studying the alleged beneficial properties of omega-3 fatty acids, not to mention the billion dollar industry producing and selling fish oil capsules based on a hypothesis that was questionable from the beginning."

Extra Weight Harms Quality of Life In Elderly Women, But Not Men

A new study published online before print April 30, 2014 in the Journal of Aging and Health explored the impact of differential degrees of obesity on health-related quality of life (HRQL) in the Korean elderly between the ages of 65 and 74 years.

Compared with the lowest waist circumference (WC) quintile, the women in the fourth and fifth quintiles demonstrated significantly lower unadjusted HRQL but not the men in any quintiles. Whereas higher WC quintiles impaired mobility, usual activities, and pain/discomfort in women, the fourth WC quintile improved usual activities in men. After adjustment, only the women of the highest WC quintile reported impaired mobility

Extreme obesity worsens mobility, and comorbidity in combination with obesity worsens HRQL in elderly women. Monitoring and controlling comorbidity and maintaining adequate WC decreases the risks of lowered HRQL in Korean elderly women.