Health News Report

Monday, May 24, 2021

No link between milk and increased cholesterol according to new study of 2 million people

UNIVERSITY OF READING

Regular consumption of milk is not associated with increased levels of cholesterol, according to new research.

A study published in the International Journal of Obesity looked at three large population studies and found that people who regularly drank high amounts of milk had lower levels of both good and bad cholesterol, although their BMI levels were higher than non-milk drinkers. Further analysis of other large studies also suggests that those who regularly consumed milk had a 14% lower risk of coronary heart disease.

The team of researchers took a genetic approach to milk consumption by looking at a variation in the lactase gene associated with digestion of milk sugars known as lactose.

The study identified that having the genetic variation where people can digest lactose was a good way for identifying people who consumed higher levels of milk.

Prof Vimal Karani, Professor of Nutrigenetics and Nutrigenomics at the University of Reading said:

"We found that among participants with a genetic variation that we associated with higher milk intake, they had higher BMI, body fat, but importantly had lower levels of good and bad cholesterol. We also found that those with the genetic variation had a significantly lower risk of coronary heart disease. All of this suggests that reducing the intake of milk might not be necessary for preventing cardiovascular diseases."

The new research was conducted following several contradictory studies that have previously investigated the causal link between higher dairy intake and cardiometabolic diseases such as obesity and diabetes. To account for inconsistencies in sampling size, ethnicity and other factors, the team conducted a meta-analysis of data in up to 1.9 million people and used the genetic approach to avoid confounding.

Even though the UK biobank data showed that those with the lactase genetic variation had 11% lower risk of type 2 diabetes, the study did not suggest that there is any strong evidence for a link between higher milk intake and increased likelihood of diabetes or its related traits such as glucose and inflammatory biomarkers.

Professor Karani said:

"The study certainly shows that milk consumption is not a significant issue for cardiovascular disease risk even though there was a small rise in BMI and body fat among milk drinkers. What we do note in the study is that it remains unclear whether it is the fat content in dairy products that is contributing to the lower cholesterol levels or it is due to an unknown 'milk factor'".

A low-calorie ketogenic diet can help testosterone levels in overweight men

New research reveals that a low-calorie ketogenic diet can help testosterone levels in overweight men, reducing overall levels of obesity

A very low-calorie ketogenic diet can help testosterone and sex hormone (SHBG) levels in overweight men, according to a study being presented at the 23rd?European Congress of Endocrinology (e-ECE 2021), on Monday 24 May 2021 at 14:06 CET (http://www.ece2021.org). The study found that after following a recommended low-calorie ketogenic diet for four weeks, body weight, fat mass and body mass index (BMI) significantly decreased and a substantial increase of total testosterone and SHBG levels were also found. Testosterone is responsible for sexual and reproductive functions. However, it plays a significant role in calorie utilisation and metabolism as well.

This study was the first of its kind to examine the effect of a very low-calorie ketogenic diet on testosterone and SHBG levels and therefore highlighted the tight relation between insulin action, energy balance, and testicular function. As men who are overweight or obese can also suffer from low levels of testosterone and SHBG levels, the data suggests that further research into a low-calorie ketogenic diet and its effect on male testosterone and SHBG levels may be a promising area for additional research.

The worldwide prevalence of obesity nearly doubled between 1980 and 2008. According to country estimates for 2008, over 50% of men in the WHO European Region were overweight, and roughly 20% were obese. Obesity can lead to diabetes and heart disease, as well as psychological problems.

To tackle this, various lifestyle changes, activities and treatments are widely recommended, and a ketogenic diet is becoming increasingly recognised as one of them. The diet consists of little protein and very little carbohydrates, and when done as very-low calorie a daily intake of less than 800 calories is advised. A very low-calorie ketogenic diet has previously been found to reduce body weight, glycaemia and insulinemia, but its effects on total testosterone and SHBG levels were less clear, until now.

Dr Angelo Cignarelli and a team of colleagues from the University of Bari in Italy investigated whether this controlled diet would have the same, positive effect that it does on overall bodyweight on total testosterone and SHBG levels. The 17 male subjects in the study underwent a low-calorie ketogenic diet for four weeks, and various tests were carried out before and after one (1) and four (4) weeks.

"We aimed to evaluate the response of total testosterone and sex hormone levels to a very low-calorie ketogenic diet in a cohort of overweight or obese non-diabetic male subjects and what we found was that there is a noticeable relation between a specific, controlled diet and insulin action, energy balance, and testicular function," says Dr Cignarelli.

This is the first study that has evaluated the early response of androgen levels to the institution of a very low-calorie ketogenic diet, and highlights the relation between insulin action, energy balance, and testicular function. Results from this study now prove that a very low-calorie ketogenic diet can positively effect on total testosterone and SHBG levels. Further analysis will provide information about the effect of this nutritional intervention on additional clinical outcomes related to testosterone such as sexual function, muscle strength and quality of life.

Study: Diet to lower blood pressure also improved other factors in cardiac health

Findings support policy measures to reduce sodium levels in American diet

BETH ISRAEL DEACONESS MEDICAL CENTER

Research News

BOSTON - Cardiovascular disease (CVD) is the leading cause of death in the United States. Public health advocates frequently site Americans' high-sodium diet as one factor in the nation's cardiac health. While sodium has been definitively linked to high-blood pressure -- a key risk factor for CVD -- few rigorously controlled studies make the direct causal link between high sodium intake and cardiovascular damage, heart attack, or stroke.

In a new analysis, researchers from Beth Israel Deaconess Medical Center (BIDMC) examined three cardiovascular biomarkers, which are measurable indicators of cardiovascular health in the blood, to determine whether diet directly impacts cardiac health. Analyzing blood samples from clinical trial participants adhering to strict dietary regimens, the team showed that a diet proven to lower elevated blood pressure, known as the DASH diet, reduces inflammation. The findings, published in the Journal of the American College of Cardiology, also showed that the DASH diet, alone or in conjunction with a low-sodium diet, reduces heart injury and strain.

"Our study represents some of the strongest evidence that diet directly impacts cardiac damage, and our findings show that dietary interventions can improve cardiovascular risk factors in a relatively short time period," said first and corresponding author Stephen Juraschek, MD, PhD, Assistant Professor of Medicine at BIDMC and Harvard Medical School (HMS). "The data reinforce the importance of a lifestyle that includes a reduced-sodium, DASH diet rich in fruits, vegetables and whole grains to minimize cardiac damage over time."

The DASH, or Dietary Approaches to Stop Hypertension, diet has been proven to reduce blood pressure. It emphasizes consuming fruits, vegetables, low-fat dairy products, whole grains, poultry, fish and nuts while limiting saturated fats, total fat, cholesterol, red meat, sweets and sugar-containing beverages. Developed in the 1990s with the specific goal of lowering blood pressure, the well-studied diet has also been shown to prevent cancer, osteoporosis, diabetes, heart attack, stroke and cardiovascular disease.

The current study builds on two recent analyses in which Juraschek and colleagues found that the DASH diet lowered markers of cardiac injury, strain, and inflammation. However, these prior studies did not specifically examine the effects of sodium reduction, alone or combined with a DASH-style dietary program, on cardiovascular health.

In the team's current analysis, Juraschek and colleagues, including senior author, Kenneth J. Mukamal, MD, MPH, Associate Professor of Medicine at BIDMC and HMS, analyzed stored specimens from the DASH-Sodium study, conducted at four medical centers in the United States in between 1997 and 1999. In that previous study, researchers enrolled 412 participants with elevated blood pressure and randomly assigned them to either the DASH diet or a control diet designed to reflect a typical American diet. Within those two groups, each participant was assigned to one of three sodium levels (low, medium or high) for four weeks. A controlled-feeding study, all meals and snacks were provided to participants who ate one main meal per day under observation and consumed the rest off-site.

Juraschek and team analyzed stored specimens from this study for three biomarkers, or measurable substances in the blood that have been shown to predict cardiovascular events in adults without known cardiovascular disease. The biomarkers, which are proteins known as high sensitivity cardiac troponin I (hs-cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP) and high sensitivity C-reactive protein (hs-CRP), are linked to three distinct pathways of subclinical cardiac damage: injury, stress and inflammation, respectively.

The analysis revealed that, among trial participants on the DASH diet, biomarkers linked to cardiac damage and inflammation declined by 18 percent and 13 percent respectively. Participants combining the DASH diet with reduced-sodium impact experienced the greatest reductions in the biomarkers for injury and stress -- 20 percent and 23 percent, respectively -- while inflammation was not significantly impacted.

While the DASH diet alone did not reduce the biomarker for stress, the stress biomarkers declined by 19 percent in study participants who consumed low sodium diets, whether they followed the DASH diet or the control diet. However, lowering sodium alone did not have a beneficial impact on cardiac injury or inflammation.

"We used highly sensitive markers of subclinical cardiovascular disease to show how two dietary strategies can improve distinct mechanisms of subclinical cardiac injury in a relatively short time period, suggesting that the improvements in cardiovascular disease risk factors observed from a reduced-sodium, DASH diet may also reduce concurrent cardiac damage," said Juraschek. "Our study has important clinical implications, and these findings should strengthen public resolve for public policies that promote the DASH dietary pattern and lower sodium intake in the United States and globally."

Study finds women with osteoporosis and low bone density are at increased risk of hearing loss

Bisphosphonates, commonly prescribed to reduce bone fracture risks, were not shown to alter likelihood of hearing loss

BRIGHAM AND WOMEN'S HOSPITAL

Research News

- Hearing loss is the third most common chronic health condition in the United States. Previous studies of people with hearing loss have uncovered higher prevalence of osteoporosis -- a disease in which the bones become weak and brittle -- and low bone density (LBD). But research on whether these conditions may influence risk of hearing loss over time is scarce. It is also unknown whether hearing loss can be avoided by taking bisphosphonates, the primary medication used to prevent fractures in people with reduced bone density. As part of the Conservation of Hearing Study (CHEARS), researchers from Brigham and Women's Hospital analyzed data from nearly 144,000 women who were followed for up to 34 years. They found that risk of subsequent moderate or worse hearing loss was up to 40 percent higher in study participants with osteoporosis or LBD. The study, published in the Journal of the American Geriatric Society, also found that bisphosphonates did not alter risk of hearing loss.

"Adult onset hearing loss is typically irreversible; therefore, CHEARS focuses on identifying potentially modifiable risk factors that may contribute to hearing loss," said study leader Sharon Curhan, MD, ScM, of the Channing Division of Network Medicine at the Brigham. "We were inspired by a recent study that found that bisphosphonates may help prevent noise-induced hearing damage in mice. We wanted to investigate whether bisphosphonates alter risk of hearing loss in adults, in addition to whether there is a longitudinal association between osteoporosis or LBD and risk of subsequent hearing loss."

For their analysis, the researchers used data from the decades-long Nurses' Health Study (NHS) and NHS II, two large ongoing prospective cohorts of female registered nurses, established in 1976 and 1989, respectively. The researchers examined hearing loss that was moderate or worse in severity, as self-reported by participants on questionnaires completed every two years. Additionally, they used the CHEARS Audiometry Assessment Arm to incorporate data on participants' audiometric thresholds (a measure of hearing sensitivity based on the loudness of sound).

In both the NHS and NHS II cohorts, the researchers found that the risk of hearing loss was higher in women with osteoporosis or LBD, and that taking bisphosphonates did not moderate the elevated risk. More research is required to understand whether the type, dose or timing of bisphosphonate use might influence its impact.

The researchers found that a history of vertebral fracture was associated with up to a 40 percent higher risk of hearing loss, but the same did not hold true for hip fractures, the two most common osteoporosis-related fractures. "The differing findings between these skeletal sites may reflect differences in the composition and metabolism of the bones in the spine and in the hip," Curhan said. "These findings could provide new insight into the changes in the bone that surrounds the middle and inner ear that may contribute to hearing loss."

While the underlying mechanisms by which osteoporosis and LBD may contribute to aging-related hearing loss remain unclear, the researchers suggest that abnormal bone remodeling and changes in the pathways involved in maintaining bone homeostasis may influence the integrity of the bone that protects the nerves and structures involved in hearing or alter ion and fluid metabolism in the cochlea, the main structure involved in hearing.

Advantages of using data from these well-characterized cohorts include the large study population, extensive array of detailed information, impressive follow-up rates and reliable information on health-related outcomes, as the participants are trained health care providers. However, the researchers note that their study is limited in its generalizability, as participants are predominantly white, with similar educational achievements and socio-economic statuses. Curhan points out that additional studies that examine these associations in men and non-white women would be informative.

Additionally, the investigators plan to examine in the future whether calcium and vitamin D intake are associated with hearing loss, as they have been shown to help prevent osteoporosis. Previously, the researchers found that eating a healthy diet, staying physically active, not smoking, and maintaining a healthy weight all help reduce the risk of hearing loss.

"Osteoporosis and low bone density may be important contributors to aging-related hearing loss," Curhan said. "Building lifelong healthy diet and lifestyle habits could provide important benefits for protecting bone and hearing health in the future."

Regular physical activity linked to better organized preteen brains

Data from ~6,000 9- and 10-year-old show positive effects on the developing 'connectome'

BOSTON CHILDREN'S HOSPITAL

Research News

IMAGE: THE IMAGES SHOW POSITIVE EFFECTS OF PHYSICAL ACTIVITY (IN ORANGE) AND NEGATIVE EFFECTS OF BMI (IN BLUE) ON LOCAL BRAIN NETWORKS. AREAS WHERE THE EFFECTS OF EXERCISE AND BMI OVERLAP... view more
CREDIT: SKYLAR BROOKS, COMPUTATIONAL NEUROSCIENCE LABORATORY, BOSTON CHILDREN'S HOSPITAL

Regular physical activity has positive effects on children's developing brain circuits, finds a Boston Children's Hospital study using neuroimaging data from nearly 6,000 early adolescents. Physical activity of any kind was associated with more efficiently organized, flexible, and robust brain networks, the researchers found. The more physical activity, the more "fit" the brain.

Findings were published in Cerebral Cortexon May 14.

"It didn't matter what kind of physical activity children were involved in - it only mattered that they were active," says Caterina Stamoulis, PhD, principal investigator on the study and director of the Computational Neuroscience Laboratory at Boston Children's. "Being active multiple times per week for at least 60 minutes had a widespread positive effect on brain circuitry."

Specifically, Stamoulis and her trainees, Skylar Brooks and Sean Parks, found positive effects on circuits in multiple brain areas. These circuits play a fundamental role in cognitive function and support attention, sensory processing, motor function, memory, decision-making, and executive control. Regular physical activity also partially offset the effects of unhealthy body mass index (BMI), which was associated with detrimental effects on the same brain circuitry.

Harnessing big data

With support from the National Science Foundation's Harnessing the Data Revolution and BRAIN Initiative, the researchers tapped data from the long-term, NIH-sponsored Adolescent Brain Cognitive Development (ABCD) study. They analyzed functional magnetic resonance imaging (fMRI) data from 5,955 9- and 10-year-olds and crunched these data against data on physical activity and BMI, using advanced computational techniques developed in collaboration with the Harvard Medical School High Performance Computing Cluster.

"Early adolescence is a very important time in brain development," notes Stamoulis. "It's associated with a lot of changes in the brain's functional circuits, particularly those supporting higher-level processes like decision-making and executive control. Abnormal changes in these areas can lead to risk behaviors and deficits in cognitive function that can follow people throughout their lifetime."

Gauging functional brain organization

The functional MRI data were captured in the resting state, when the children were not performing any explicit cognitive task. This allows analysis of the "connectome" -- the architecture of brain connections that determines how efficiently the brain functions and how readily it can adapt to changes in the environment, independently of specific tasks.

The team adjusted the data for age, gestational age at birth, puberty status, sex, race, and family income. Physical activity and sports involvement measures were based on youth and parent surveys collected by the ABCD study.

The analysis found that physical activity was associated with positive brain-wide network properties reflecting the connectome's efficiency, robustness, and clustering into communities of brain regions. These same properties were detrimentally affected by high BMI. Physical activity also had a positive effect on local organization of the brain; unhealthy BMI had adverse impacts in some of the same areas.

"Based on our results, we think physical activity affects brain organization directly, but also indirectly by reducing BMI, therefore mitigating its negative effects," Stamoulis says.

Optimal functional brain structure consists of small regions or "nodes" that are well connected internally and send information to other parts of the brain through strong, but relatively few, long-range connections, Stamoulis explains.

"This organization optimizes the efficiency of information processing and transmission, which is still developing in adolescence and can be altered by a number of risk factors," she says. "Our results suggest that physical activity has a protective effect on this optimization process across brain regions."

Friday, May 21, 2021

SPRINT study confirms controlled blood pressure important in preventing heart disease and stroke

UH Cleveland Medical Center and Case Western Reserve University's Jackson T. Wright Jr., MD, PhD, and Mahboob Rahman, MD, authors on NEJM study showing persistent positive effects of 120 target blood pressure

UNIVERSITY HOSPITALS CLEVELAND MEDICAL CENTER

Research News

CLEVELAND - Follow-up data from the landmark SPRINT study of the effect of high blood pressure on cardiovascular disease have confirmed that aggressive blood pressure management -- lowering systolic blood pressure to less than 120 mm Hg -- dramatically reduces the risk of heart disease, stroke, and death from these diseases, as well as death from all causes, compared to lowering systolic blood pressure to less than 140 mm Hg. Systolic blood pressure (SBP) is the upper number in the blood pressure measurement, 140/90, for example.

In findings published in the May 20, 2021 issue of the New England Journal of Medicine, investigators presented new evidence of the effectiveness of reducing SBP to a target range of less than 120 mm Hg.

Jackson T Wright Jr. MD, PhD., and Mahboob Rahman MD, investigators from University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, played a lead role in the design, conduct, analyses and publication of the SPRINT trial. UH and CWRU coordinated one of the five Clinical Center Networks (CCNs) across the country selected to conduct the trial that had recruited more than 9,300 participants.

"This final report of the findings from SPRINT, now including all cardiovascular and mortality trial events, confirms the benefit of more aggressive BP lowering compared the previously recommended target of less than 140/90 mmHg," said Dr. Wright, Director of the Clinical Hypertension Program at UH and Professor Emeritus of Medicine at CWRU.

SPRINT was a randomized controlled clinical trial sponsored by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health. Beginning in late 2009, it enrolled more than 9,000 participants at least 50 years old who had SBP 130 to 180 and had increased cardiovascular disease risk. The NIH ceased randomly assigned treatments in 2015, when data was presented to the Data and Safety Monitoring Board showing treatment to SBP of less than 120 decreased the rate of a composite cardiovascular disease (CVD) outcome by 25 percent and the rate of all-cause death by 27 percent.

Researchers reported these findings in 2015, but continued to collect data into July 2016. The current paper confirms and enhances the earlier findings.

SPRINT's primary outcome was lower risk of having one of a composite of different types of cardiovascular disease outcomes related to blood pressure. These included heart attack, an acute coronary syndrome not resulting in a heart attack, stroke, acute heart failure, or death from cardiovascular disease.

The final results showed the risk of the primary outcome of the trial was decreased 27 percent and death from all causes was decreased by 25 percent in the group treated to less than 120 mm Hg compared to the group treated to less than 140 mm Hg.

"One criticism of the original SPRINT findings was that, of the components of the primary outcome, only heart failure and death due to CVD were significantly lower in the intensively treated group," Cora E. Lewis, MD, Professor and Chair of the Department of Epidemiology in the University of Alabama at Birmingham School of Public Health, and primary investigator of the study. "The final results found that risk of heart attack, along with heart failure, and death from CVD, was significantly lower in the group treated to less than 120, and the risk of the primary outcome excluding heart failure was still significantly lower in the more intensively treated group."

SPRINT also collected data on safety of the interventions. The investigators anticipated that serious adverse events, including hospitalizations overall, as well as hospitalizations and emergency room visits for specific conditions of interest, might be related to more intensive treatment of blood pressure with medicines. The final paper reports that overall serious adverse events did not differ, but there were more cases of some of the conditions of interest in the group treated to SBP of less than 120, including low blood pressure, fainting and acute injury to the kidneys, which usually resolved within one year. Falls leading to injury did not differ.

Hypertension, high blood pressure, is a hugely important risk factor for the leading cause of death worldwide: cardiovascular disease or CVD, said Dr. Rahman. "CVD has been the number one killer in the U.S. for decades, even in 2020, when we were dealing with COVID-19, which was the number three killer that year in the U.S. Elevated blood pressure is the leading contributor to preventable deaths worldwide of 67 risk factors studied (including tobacco)." "The take-home message from SPRINT is to talk to your doctor about your blood pressure to determine a good goal for you based on your overall cardiovascular disease risk. Then work with your doctor to achieve that goal," said Dr. Rahman.

Prior to the SPRINT trial, research had shown that treating high blood pressure helped decrease risk of CVD, but the optimum SBP goal was unknown. In 2007, a group of experts in high blood pressure research suggested that determining the appropriate goal of SBP to reduce the risk of heart disease was of the utmost importance in preventing complications from hypertension.

"We know a lot about how to prevent and treat hypertension and SPRINT continues to greatly expand this knowledge, including the benefits of treatment on the heart, kidney and brain," said David Goff, M.D., Ph.D., director of the Division of Cardiovascular Sciences at NHLBI. "As we implement what we know, more research is still needed to develop more effective prevention strategies for hypertension, improve its monitoring and control, and reduce the large health disparities associated with this disorder. Research teams supported by the NIH are continuing to work on these challenges."

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Nearly half of adults age 20 years and older in the United States have high blood pressure, which is defined as SBP of 130 or more or diastolic blood pressure (the lower number) of 80 or more. World Hypertension Day was May 17, 2021, recognizing how important high blood pressure is to the health of the world's population.

Thursday, May 20, 2021

No safe level of alcohol consumption for brain health

No safe dose of alcohol for the brain was found. Moderate consumption is associated with more widespread adverse effects on the brain than previously recognised. Individuals who binge drink or with high blood pressure and BMI may be more susceptible. Detrimental effects of drinking appear to be greater than other modifiable factors. Current ‘low risk’ drinking guidelines should be revisited to take account of brain effects.

Complete report