MedicalResearch.com Interview with:
Aidan Gribbon M.Sc., CSEP-CEP
From the Healthy Active Living and Obesity Research Group
Children’s Hospital of Eastern Ontario Research Institute
Ottawa, Ontario, Canada
Medical Research: What is the background for this study?
Response: The background for the study is that sedentary pursuits, such as video games, are omni-present in the daily lives of adolescents. Manufacturers of active video games (AVG) have been marketing them as a ‘healthy’ alternative to seated video games, with the possibility of preventing/treating obesity in this age group. Although, active video games have been shown to acutely increase energy expenditure over their seated counterparts, no study has examined their compensatory adjustments in energy expenditure or energy intake.
Medical Research: What are the main findings?
Response: The main finding of this paper was that although active video games are not associated with an increased food intake, they are compensated for by a decrease in physical activity such that their benefit of a reduction in the energy gap underlying weight gain is offset within 24 hours.
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MedicalResearch.com Interview with:
Nia S. Mitchell, MD, MPH
Assistant Professor
Division of General Internal Medicine
Department of Medicine
University of Colorado Anschutz Medical Campus
Medical Research: What is the background for this study? What are the main findings?Dr. Mitchell: Despite decades of obesity research two issues remain elusive in weight management: significant, long-term weight loss and weight loss maintenance and widely accessible programs. There are numerous weight loss programs out there, but there is little evidence of the long-term effectiveness of many programs. Furthermore, these programs may not be accessible to the general population because they are too expensive and may not be geographically available.
I chose to evaluate the Take Off Pounds Sensibly (TOPS) program because I thought it had the potential to address these issues. TOPS is a nationally-available, nonprofit, low-cost, peer-led weight loss program. It costs only $92 per year--$32 is the annual fee plus local chapter dues that average about $5 per month--and any four people can start a TOPS chapter, so it can be implemented and disseminated widely.
The main objective of this study was to determine the weight change for individuals who consecutively renewed their membership in TOPS. We looked at people who joined TOPS from 2005 to 2011, so they could have been followed for up to seven years. We found that people who join TOPS and consecutively renew their annual membership can lose a clinically significant amount of weight and maintain the weight loss for up to seven years. Clinically significant weight loss is defined as weight loss of at least 5% of initial weight, because with a 5% weight loss people with weight-related medical conditions, such as diabetes, can see an improvement in their conditions. Therefore, a diabetic who weighs 200 pounds may see an improvement in her blood sugar control if she loses 10 pounds.
In our study, fifty percent of individuals had clinically significant weight loss in their first year in the program, and 62% of those renewed their annual membership consecutively for seven years had clinically significant weight loss at seven years. This was exciting because many people who lose weight tend to gain it back. I often say that the unfortunate natural history of weight loss tends to be weight re-gain. However, the majority of these individuals maintained a clinically significant weight loss.
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MedicalResearch.com Interview with:
Catarina Rendeiro Ph.D.
Post-doctoral Research Associate
Rhodes lab University of Illinois
Urbana, Illinois
Medical Research: What is the background for this study? What are the main findings?
Dr. Rendeiro: The motivation for this study emerges in the context of understanding the link between sugar intake, particularly fructose, and the rising obesity epidemic that we are currently facing. Overeating and lack of physical activity certainly play major roles in obesity, but the sources of calories are also important. Fructose, a simple monosaccharide found in fruit and vegetables, and composing half of sucrose (i.e., table sugar), has been on the increase in Western diets. In our rodent study, 18% of dietary calories were derived from sugar, either fructose or glucose. This level is similar to typical American diets. However, the fructose diet resulted in increased weight gain and fat deposition and reduced physical activity even though food intake was similar between the two groups. It is also important to note that our animals were consuming their regular amount of calories, not overeating. Only the source of sugar was different between experimental groups, and still calorie-for-calorie, fructose caused greater weight gain and less physical activity than glucose.
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MedicalResearch.com Interview with:
Christopher X WongMBBS MSc PhD
Clinical Research Fellow | Clinical Trial Service Unit, Oxford
Clinical Senior Lecturer | Centre for Heart Rhythm Disorders, Adelaide
Clinical Trial Service Unit, University of Oxford
Roosevelt Drive, Oxford
Medical Research: What is the background for this study? What are the main findings?Dr. Wong: Atrial fibrillation is an increasingly common heart rhythm disorder. This study demonstrates that even small increments in obesity are associated with a significantly increased risk of atrial fibrillation. Our data suggest that for every 1 unit reduction in body mass index there may be a 3-5% reduction in atrial fibrillation; for every 5 unit reduction, there may be 10-29% reductions. It should also be noted that this is likely to be a significant underestimate of the effect of weight reduction on atrial fibrillation rates as weight control has favourable effects on other risk factors for atrial fibrillation, such as hypertension and diabetes. Given the more than 45 million people with atrial fibrillation worldwide, even small but widespread reductions in obesity would thus help contain this ‘epidemic’ of atrial fibrillation.
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MedicalResearch.com interviewDorota Kaminska, MSc
Department of Clinical Nutrition
University of Eastern FinlandMedicalResearch: What is the background for this study? What are the main findings?Response: The prevalence of obesity is increasing worldwide, making it one of the biggest health problems currently facing both developed and developing countries. Obesity is considered a primary risk factor for developing type 2 diabetes. While the majority of people with type 2 diabetes are obese, most of obese people do not develop diabetes, indicating that obesity is not the only risk factor for type 2 diabetes. Both obesity and type 2 diabetes are multifactorial complex diseases that are caused by a combination of genetic, environmental, and lifestyle factors. Results from twin studies suggest that genetic factors explain 50% to 90% of the variance in body mass index (BMI) and from 45% to 85% of the diabetes risk. However genetic variations identified by genome wide association studies (GWAS) explain only 2-4% of the obesity risk and 5-10% of the type 2 diabetes risk. Several options have been debated to be a source of so called “missing heritability”, including, among others, structural DNA variations, gene-gene and gene-environment interactions, epigenetic modifications and RNA splicing.
We used adipose tissue samples from Kuopio Obesity Surgery (KOBS), very low calorie diet (VLCD), Metabolic Syndrome in Men (METSIM) and European Network on Functional Genomics of Type 2 Diabetes (EUGENE2) studies to determine alternative splicing pattern of selected genes.
The study focused on determining the effects of obesity and weight loss on alternative splicing of metabolically active genes (TCF7L2 and INSR). We showed that alternative splicing of both genes is dysregulated in obesity and type 2 diabetes, resulting in impaired insulin action in adipose tissue. Additionally we demonstrated, that obesity induced changes in splicing can be reversed by weight loss induced by gastric bypass surgery or very low calorie diet.
Furthermore, the study identified alternatively spliced genes in the genomic regions associated with obesity risk, demonstrating that splicing of the MSH5 gene in subcutaneous fat is regulated by weight loss. The study also found that body mass index is a main determinant of TRA2B, BAG6 and MSH5 splicing in subcutaneous fat; however, the functional consequences of this finding require further investigation. These findings imply that the obesity-associated gene variants might act through regulation of splicing which in turn might underlie the pathogenesis of obesity in individuals carrying the risk variants.
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MedicalResearch.com Interview with:
Michelle Schmiegelow, MD, PhD-student
Hjertemedicinsk Forskning
Gentofte Universitetshospital
Hellerup
Medical Research: What is the background for this study?
Dr. Schmiegelow: Obesity has become a worldwide epidemic, but the excess cardiovascular risk observed in obese individuals may primarily be attributable to metabolic mediators, rather than obesity per se. Several studies conducted in primarily non-Hispanic white populations suggest that obese individuals without the metabolic syndrome, defined as metabolically healthy obese, have a cardiovascular risk similar to that of normal weight metabolically healthy individuals.
We used prospectively collected data from the Women’s Health Initiative studies to evaluate whether obesity unaccompanied by metabolic abnormalities was associated with increased risk of cardiovascular disease (CVD) across racial/ethnic subgroups in postmenopausal women. Additionally, we examined whether the use of the metabolic syndrome to define the metabolically healthy obese applied to the various racial/ethnic subgroups by quantifying the number and type of metabolic syndrome components.
All women were classified by obesity level and metabolic health status at baseline. The women were thus categorized according to body mass index (BMI, kg/m2) into normal weight (BMI 18.5-24.9 kg/m2), overweight (25-29.9 kg/m2) and obese (30.0 kg/m2) women. Metabolic health status was first defined by presence of the metabolic syndrome (yes/no), and second by number of metabolic syndrome components. In accordance with the International Diabetes Federation and the American Heart Association/National Heart, Lung, and Blood Institute we defined the metabolic syndrome as any two of the following (criteria for women): increased waist circumference ≥80 cm; increased level of triglycerides ≥150 mg/dL (≥1.7 mM); decreased level of HDL-C <50 mg/dL (<1.3 mM); increased blood pressure with either systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg, or treatment with antihypertensive drugs; and impaired fasting serum glucose ≥100 mg/dL (6.1 mM).
Medical Research: What are the main findings?Dr. Schmiegelow: The study population comprised 14,364 women without diabetes or prior cardiovascular disease. The women had a median age of 64 years (interquartile range 57–69), and 47% were white, 36% were black and 18% were Hispanic. Over a median follow-up of 13 years (interquartile range 12–14 years), 1,101 women (7.7%) had a first cardiovascular event.
The main findings of this study were that metabolic abnormalities appeared to confer more cardiovascular risk among black women than among white women. Consistent with other studies, among white women without the metabolic syndrome, obesity was not associated with increased cardiovascular risk compared with normal weight women. Conversely, black overweight and black obese women had increased cardiovascular risk compared with normal weight black women without the metabolic syndrome, even in absence of the metabolic syndrome.
According to number of metabolic syndrome components, black overweight or obese women with just two metabolic abnormalities had increased risk of cardiovascular disease, although they would be considered “metabolically healthy” based on the standard definition, particularly since one of these abnormalities were abdominal obesity for 79% of overweight and 98% of obese women, irrespective of race/ethnicity. White obese women with three metabolic abnormalities did not have a statistically significantly increased cardiovascular risk compared with normal weight metabolically healthy women. Thus, cardiovascular disease risk appeared to be elevated in black women by the presence of only two or three metabolic abnormalities to a degree that would require four or more metabolic abnormalities among white women. These findings did not appear to be driven by any particular combination of metabolic abnormalities.
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MedicalResearch.com Interview with:
Martin Reinhardt, MD
Postdoctoral Fellow
PECRB, NIDDK, NIH
Phoenix, AZ 85016
Medical Research: What is the background for this study? What are the main findings?
Dr. Reinhardt: It can be very difficult for some people with obesity to lose weight despite great efforts. There is an immense deal of individual variability in weight loss success. Beyond differences in diet adherence, it is not clear what causes this variability in weight loss.
Through a study conducted at our facilities at the National Institutes of Health in Phoenix, Arizona, we have now shown that individual differences in biology – more precisely, differences in the amount of energy bodies use during fasting – make it difficult for certain obese people to lose weight.
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MedicalResearch.com Interview with:
Edward "Ted" Weiss, Ph.D.
Associate Professor
Department of Nutrition and Dietetics
Saint Louis University Saint Louis MO
Medical Research: What is the background for this study? What are the main findings?
Dr. Weiss: Results from one of our previous study yielded a surprising result that diet-induced weight loss improved insulin sensitivity (major diabetes risk factor) by the same amount as exercise induced weight loss. We thought that the exercise-induced weight loss would have yielded benefits from the weight loss itself but also from a weight loss-independent benefit that has been reported in other studies. One explanation for dietary restriction providing the same benefit of exercise was that it also provides benefits besides those that are attributable to weight loss. Our recently completed/published study was designed to evaluate this possibility and the finding do suggest what we hypothesized... i.e. that dietary restriction provides benefits above and beyond that which are attributable to weight loss.
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MedicalResearch.com Interview with: Dr Margaret Ashwell OBE, FAfN, RNutr (Public Health)
Ashwell Associates
Ashwell, Hertfordshire, United Kingdom.
Visiting Research Fellow, Oxford Brookes University
MedicalResearch: What are the main findings from this study?
Dr. Ashwell: In this study, the authors explore the differences in CVD risk factors between overweight and non-overweight people (by BMI) according to their shape (waist-to-height ratio -WHtR) Data for their analysis was taken from the Health Survey for England 2009 (HSE). They found significant differences in levels of total cholesterol (TC) and glycated haemoglobin (HbA1c—a measure of blood sugar control used to diagnose diabetes).
Out of 2917 people aged 16 years and over, 346 classified as ‘normal’ by BMI, have WHtR exceeding 0.5 (12% of the total,sample, or 34% of normal weight people). These could be called non-overweight ‘apples’, who have a lot of fat around the waist but not a high BMI.
The researchers classified the HSE population into four groups (2×2) using standard boundary values of BMI (above or below 25kg/m2) and WHtR (above or below 0.5). The group with ‘low/normal BMI but high WHtR (non-overweight ‘apples’) had significantly higher mean TC than the group with high BMI but low WHtR (overweight ‘pears’—people with a higher than normal BMI but less fat around the waist): 5.73mmol/L vs. 4.98mmol/L. Similarly, HbA1c levels were higher among non-overweight ‘apples’ than among overweight ‘pears’ (5.62% vs. 5.33%). These differences were similar and also significant in both sexes.
MedicalResearch: Why do you say that piece so string can be used for primary screening?
Dr. Ashwell: Since a good boundary value for waist-to-height ratio is 0.5, you don't even need a tape measure to screen those at risk. It can be done with a piece of string. Measure the height of child with string, fold it in half and see if it fits around his/her waist. If it doesn't, that child should proceed to the next stage of screening.
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MedicalResearch.com Interview with:
Matthew Pearce
NHS Gloucestershire Clinical Commissioning Group
UK
Medical Research: What is the background for this study? What are the main findings?
Response: Despite evidence to suggest that the prevalence of childhood obesity in the UK has stabilized in recent years, we know that approximately one in five children start their school life either overweight or obese, increasing to one in three children by the last year in primary school. Our research was the first to undertake an in-depth analysis on the UK’s National Child Measurement Programme (NCMP) and retrospectively track the weights of individual children over a 7-year period. Our study included a sample of 1863 children in South Gloucestershire, Bristol in the UK.
Our results were found to be similar to cross sectional data with obesity prevalence approximately doubling between the first (4/5yrs old) and last year (10/11yrs old) of primary school. Our findings provide little reassurance that those children who are obese in early childhood ‘grow out of ’ excess adiposity. Including overweight, we found that 84% of obese children at Reception year went on to be either overweight or obese by Year 6. Although previous studies have failed to identify any significant differences in BMI change between boys and girls during mid-childhood, our research found that more boys than girls dropped a weight category (from overweight or obese) by the time they reached Year 6. We found that the odds ratios of being overweight (BMI ?85th percentile) or obese (?95th percentile) based on BMI at Reception were similar to published literature. Our data found children who are within the upper range of the healthy weight category (75th–85th percentile) at Reception had an increased risk of being overweight or obese by the time they reach year 6. (more…)
MedicalResearch.com Interview with:
Dr. Dragos Petrescu
Department of Public Health and Primary Care
Cambridge
Medical Research: What is the background for this study? What are the main findings?Response: Consumption of sugar-sweetened beverages is a major contributor to obesity, particularly in children. Recent systematic reviews provide good evidence that reducing portion size reduces consumption. Similarly, evidence suggests that container shapes and product placement in supermarkets can influence consumption. The public acceptability of "nudging" -- altering properties such as the size, the shape, and location of sugar-sweetened beverages -- to improve public health is unknown. Here we compared the acceptability in UK and USA samples of government interventions to reduce consumption of sugar-sweetened beverages: three nudge interventions (limiting portion size, changing container shape, and changing shelf location) and two traditional interventions (increased taxation and an education campaign).
We found that for the majority of UK and USA samples, the education campaign and the three nudge interventions were acceptable, with education attracting most support. By contrast, only a minority of participants supported taxation.
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MedicalResearch.com Interview with:
Claudia Sikorski
Dr. rer. med. Claudia Sikorski, Dipl.-Psych.
Institut für Sozialmedizin, Arbeitsmedizin und Public Health (ISAP)
Institute of Social Medicine, Occupational Health and Public Health
Universität Leipzig, Medizinische Fakultät
Leipzig
Medical Research: What is the background for this study? What are the main findings?
Response: Obesity is a highly stigmatized condition. People with obesity are often regarded a lazy, slow and sloppy. One consequence of these negative attitudes may be discrimination, e.g. the unfair treatment of individuals with obesity. This study, conducted by Jenny Spahlholz, myself and colleagues reviews observational and experimental studies that investigated the occurrence and nature of discrimination in obesity.
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MedicalResearch.com Interview with: Rebecca Jones, MSPH
Nutrition and Health Sciences Program
Graduate Division of Biological and Biomedical Sciences
Emory University
Medical Research: What is the background for this study? What are the main findings?Response: Obesity in children is associated with a wide range of conditions later in life including heart disease, cancer, and diabetes. Even prior to adulthood, children can be affected by a host of non-communicable diseases which are affected by weight status of the child. With an increase in children who are overweight or obese globally, Dr. Chan, Director-General of the World Health Organization, announced a new initiative to combat childhood obesity at the 2014 World Health Assembly. Within childhood obesity the pre-school (under age 5) years are a critical period for prevention due the association of adiposity rebound and obesity in later years as well as the early establishment of taste preferences and attitudes around healthy eating habits. Recent evaluation of incident obesity in the United States has demonstrated a component of the course to obesity is already established by the age of five years.
Our main finding is the necessity for better surveillance and comparability of weight status, particularly overweight and obesity, in children under five across countries in the European region. 60% of countries within the region have some form of published data on this particular population however they vary based on level of national representation, cut-off criteria, age and gender. All these different factors can significantly change the prevalence estimates making it very difficult to ascertain the full nature of the problem. Based on the data which was available the European Region has reason for concern about overweight and obesity in young children.
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MedicalResearch.com Interview with:
Mark D. DeBoer, MD, MSc, MCR
Associate Professor of Pediatrics
Division of Pediatric Endocrinology, University of Virginia
Medical Research: What is the background for this study? What are the main findings?
Dr. DeBoer: The American Academy of Pediatrics recommends that children watch no more than 2 hours of TV daily. We wanted to see if children watching shorter amounts of TV were more likely to have higher weight status. We found that children in kindergarten who watched 1-2 hours a day were more than 40% more likely to be overweight and obese and gained more unhealthy weight over the next year.
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MedicalResearch.com Interview with:
May May Leung Ph.D.
Hunter College School of Urban Public Health,
City University of New York School of Public Health
New York, NY
MedicalResearch: What is the background for this study? Dr. Leung: Shanghai and New York City are two urban centers that play a key role in the global economy. However, both cities are facing elevated rates and inequitable distributions of childhood obesity. Given the role that obesity plays in the etiology of chronic diseases, this epidemic calls for interurban learning to better understand some of its diet-related determinants. In turn, this paper attempts to explore how culture, history and politics have influenced the rates and distributions of childhood obesity in Shanghai and New York City, to inform public health officials as to what approaches could be taken to address the epidemic in ‘world cities’.
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MedicalResearch.com Interview with:
Lisa J. Martin PhD
Professor Division of Human Genetics
Jessica G. Woo PhD
Associate Professor Division of Biostatistics and Epidemiology
Cincinnati Children’s Hospital Medical Center
Cincinnati, OH
MedicalResearch: What is the background for this study? Response: Obesity is a major public health concern. In the past 30 years, more and more children are being considered obese. Because treatment is challenging, researchers are looking toward prevention. The health benefits of breastfeeding over infant formula feeding are well recognized, including evidence that breastfeeding may protect against obesity. But, how much protection it provides and the reasons for protection are unclear. Thus, the purpose of this paper was to examine the relationship between breastfeeding and reduced risk of obesity later in life, with special emphasis on potential mechanisms.
MedicalResearch: What are the main findings?Response: After reviewing more than 80 studies conducted over a period of 20 years, the authors showed that breastfeeding is associated with a 10 to 20 percent reduction in obesity prevalence in childhood. Mechanisms that connect human milk and infant physiology include maternal obesity, development of a healthy gut environment (microbiome) in the infant, and the development of taste preference and diet quality. Importantly, each of these mechanisms can be influenced by biologic and social factors which may directly and indirectly affect the child’s obesity risk.
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MedicalResearch.com Interview with:
Kimberly Gudzune, MD, MPH
Assistant Professor; The Johns Hopkins University School of Medicine
Core Faculty; Welch Center for Prevention, Epidemiology, and Clinical Research
The Johns Hopkins Digestive Weight Loss Center
Medical Research: What is the background for this study? What are the main findings?
Dr.Gudzune: Changes in healthcare policy may encourage healthcare providers to screen their patients for obesity, so it is critical to then have a weight management plan if obesity is identified. Recent guidelines recommend that clinicians consider referring patients to high intensity weight loss programs. Commercial weight loss programs may be one of the options available, so providers need to know which programs help people lose weight and keep it off.
We found that only 11 out of 32 programs that we looked at had rigorous studies reporting on weight loss, which means that we do not know whether most programs work. Several well-known commercial programs have been scientifically tested and two programs, Weight Watchers and Jenny Craig, achieved significant weight loss that was sustained 12 months later.
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MedicalResearch.com Interview with:
Timothy J. Kieffer Ph.D. | Professor
Laboratory of Molecular & Cellular Medicine
Department of Cellular & Physiological Sciences
Department of Surgery | Life Sciences Institute
The University of British Columbia
Vancouver BC Canada
Medical Research: What is the background for this study? What are the main findings?
Dr. Kieffer: Previously we have examined the therapeutic potential of pancreatic precursor cells derived from human stem cells for insulin replacement in models of type 1 diabetes (PMID: 22740171 & PMID: 23771205). Here we sought to test the efficacy of cell-based insulin replacement in a model of type 2 diabetes, which is by far the most common form of diabetes. Key aspects of type 2 diabetes could be mimicked in immunodeficient mice, namely hyperglycemia and insulin resistance accompanied by excess body weight, by placing the mice on high fat diets. These diabetic mice were transplanted with human stem cell derived pancreatic precursor cells contained within macroencapsulation devices. The diabetic setting did not negatively impact the ability of the transplanted cells to mature into insulin-producing cells. Moreover, the cell transplants were able to significantly improve glucose homeostasis, particularly when combined with low doses of traditional anti-diabetic drugs. Intriguingly, the combined therapy also induced weight loss, such that treated mice were similar in weight to control mice reared on a low fat diet. (more…)
MedicalResearch.com Interview with:
Abhishek Sharma MD (on behalf of all co-authors)
Division of Cardiovascular Medicine
State University of New York Downstate Medical Center
Brooklyn, New York
MedicalResearch: What is the background for this study? Authors: Heart failure (HF) is the second most common cause of hospitalization after child delivery in the US. In general, increasing degrees of obesity have been associated with progressively worse outcomes among individuals without known cardiovascular (CV) diseases. Therefore intentional weight loss, via structured dietary and exercise training programs or bariatric surgery, has been suggested to reverse hemodynamic and cardiac structural changes associated with obesity. However, several recent studies have reported lower mortality and morbidity among heart failure patients who were overweight or obese compared with those whose weight was normal or subnormal. This phenomenon has been commonly labeled the “obesity paradox” or “reverse epidemiology.” These findings question the prognostic significance of BMI and the practice of extrapolating findings derived from the general population to HF patients.
Reasons for the association between BMI and all- cause and CV mortality and hospitalizations in HF are not fully understood. Due to contradictory results in various studies and lack of definitive data on prognostic value of BMI and its purposeful alteration in HF, the American College of Cardiology Foundation/American Heart Association do not provide any firm recommendations for purposeful weight loss in heart failure. To further explore the relationship between obesity and outcome in heart failure patients, we systematically examined the association between BMI and all- cause mortality, CV mortality and hospitalizations among patients with chronic heart failure.(more…)
MedicalResearch.com Interview with:
Tom Sanders, PhD DSc
Emeritus Professor of Nutrition & Dietetics, Diabetes and Nutritional Sciences Division,
King’s College London London, UK
Medical Research: What is the background for this study? What are the main findings?
Dr. Sanders: Controversy surrounds the effectiveness of dietary guideline for cardiovascular disease (CVD) prevention in healthy middle-aged and older men and women. These dietary guidelines are similar in UK and other Western countries and focus on modifying the overall dietary pattern so that food and nutrient targets are met. However, surprisingly the overall impact of changing the dietary pattern has never been tested in a trial. We conducted a 12-wk controlled dietary trial in 165 healthy non-smoking men and women (aged 40-70 years) to compare a diet conforming to current dietary guidelines with a traditional nutritionally balance British diet on well established (blood pressure measured by 24-h ambulatory monitoring and blood lipids) and newer predictors of cardiovascular disease risk (measures of blood vessel functioning and stiffness, inflammation and the body’s sensitivity to insulin). The dietary guideline targets were to reduce total and saturated fat intake to provide no more than 35% and 10% of the food energy, to cut salt to below 6g/day, to meet the 5-a-day recommendation for fruit and vegetables, to consume at least 1portions of oily fish a week (i.e. mackerel, salmon, sardines), to obtain half of the cereal intake from wholegrains and to restrict intake of non-milk extrinsic sugar to no more than 10% energy. Subjects were counseled by a dietitian and provided with advice tailored to their individual food preferences and were provided with some foods to assist them following the dietary advice. The control diet was a nutritionally balanced traditional British diet without restriction on salt and sugar intake. It was based around refined cereals (white bread, pasta, breakfast cereals, white rice) and potatoes with meat (red meat, meat products or poultry), but with a limited intake of oily fish (less than once a month) and wholegrain cereals. Participants allocated to control were supplied with a butter-based spread and a liquid unhydrogenated vegetable oil (palm olein) that contained 40 % saturated fatty acids. They were advised to consume three servings of full-fat dairy products (milk, yogurt and cheese), and at least one serving of fruit and two servings of vegetables each day. Both groups were given advice to limit consumption of confectionery, snack foods (chips, cake, cookies) and drink alcohol within safe limits.
Food intake records showed few differences in micronutrient intakes between diets with the exception of vitamin D where the intake and plasma 25-OH-vitamin D levels were greater on the dietary guidelines diet owing to the higher intake of oily fish. The average body weight in the group who followed the modified diet fell by 1.3 kg whilst that in the control group rose by 0.6 kg after 12 weeks, resulting in an overall difference in weight of 1.9 kg between the two groups; the equivalent difference in Body Mass Index (BMI) was 0.7 kg/m2 between the groups. Waist circumference was 1.7 cm lower in the dietary guidelines group compared to the control group.
The drop-out rate was low, with 80 participants completing on the dietary guidelines diet and 82 on the control. Adherence to the dietary advice was confirmed both with dietary records and by measuring specific biomarkers in the participants’ blood and urine. The latter indicated an increase in potassium and fibre intake in the dietary group along with a drop in sodium (salt) and saturated fat and added sugar intake. However, total sugar intake remained unchanged owing to the increase in sugar intake from fruit.
The primary outcomes were changes in day-time systolic blood pressure, endothelial function measured using the flow mediated dilation technique and total cholesterol: HDL cholesterol ratio. All other outcomes were secondary or exploratory outcomes. Significant falls in systolic blood pressure/diastolic blood pressure of 4.2/2.5 mm Hg for daytime and 2.9/1.9 mm Hg for night time were measured in the dietary group compared with the control group; the average heart rate was found to have lowered by 1.8 beats per minute. Causal mediated effects analysis based on urinary sodium excretion indicated that sodium reduction explained 2.4 mm Hg (95% CI 1.0, 3.9) of the fall in blood pressure There were no changes in endothelial dependent or endothelial independent vasodilation but arterial stiffness measured as carotid to femoral pulse wave velocity was 0. 29 m/sec lower on the dietary guidelines diet compared with the control diet. Total cholesterol:HDL cholesterol ratio was 4% lower on the dietary guidelines diet compared to the control low density lipoprotein and triglyceride concentrations were 10% and 9% lower respectively. The reduction in LDL-C (0.30 mmol/L) was greater than that achieved in most community based studies of dietary advice where the average reduction is 0.16 mmol/L but still modest compared with what can be achieved with statins (1.0 mmol/L). Compared with the control diet, the dietary guideline diet decreased low-grade inflammation (C-reactive protein). No significant change was recorded in markers for 24-h insulin secretion or insulin sensitivity, which predicts the risk of developing type 2 diabetes.
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MedicalResearch.com Interview with:
Helen P. Hazuda, Ph.D.
Professor of Medicine
Division of Nephrology
Department of Medicine
University of Texas Health Science Center
at San Antonio San Antonio, TX
Medical Research: What is the background for this study? What are the main findings?
Dr. Hazuda: The long-term effects of diet soda consumption on health outcomes is unclear, and studies in both humans and animals have raised concerns about their potentially harmful health effects including weight gain and increased cardiometabolic risk. Most human studies have focused on middle-aged or younger adults, rather than focusing specifically on people 65 years and older, a rapidly growing segment of the U.S. population that has a disproportionately high burden of cardiometabolic disease and associated healthcare costs. Therefore, our study examined prospectively the association between diet soda intake and long-term change in waist circumference in a biethnic cohort of older (65+ years) Mexican American and European American participants in the San Antonio Longitudinal Study of Aging (SALSA).
SALSA included a baseline examination (1992 – 1996) and three follow-up examinations (2000-2001, 2001-2003, and 2003-2004). The total follow-up period averaged 9.4 years. Diet soda intake, waist circumference (WC), height and weight were measured at each examination along with sociodemographic factors, leisure physical activity, diabetes mellitus, smoking, and length of follow-up.
The main finding is that over the total 9.4-year SALSA follow-up period and after adjustment for multiple potential confounders, daily diet soda users (1+ diet sodas/day) experienced an increase in waist circumference of 3.2 inches, while occasional diet soda users (>.05 < 1 diet soda/day) experienced a waist circumference increase of 1.8 inches, and nonusers of diet soda experienced a WC increase of 0.8 inches. Thus, there was a striking dose-response relationship between chronic diet soda intake and long-term increases in waist circumference. (more…)
MedicalResearch.com Interview with: Dr Rajeev Kumar Pathak MBBS, FRACP
Cardiologist and Electrophysiology Fellow
Centre for Heart Rhythm Disorders | University of Adelaide
Cardiovascular Investigation Unit | Royal Adelaide Hospital Adelaide Australia
Medical Research: What is the background for this study? What are the main findings?Response: Obesity and atrial fibrillation (AF) are dual epidemics that frequently coexist. Weight-loss reduces atrial fibrillation burden; however, whether this is sustained, has a dose effect or is influenced by weight-fluctuation is not known. In this study we evaluated the long-term impact of weight-loss and weight-fluctuation on rhythm control in obese individuals with atrial fibrillation.
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MedicalResearch.com Interview with:
Sirpa Soini, MHC, researcher
Department of General Practice and Primary Health Care
University of Helsinki
Medical Research: What is the background for this study? Response: Short-term weight loss is often successful, but he obtained results
are difficult to maintain. Therefore, a study focusing on obese people who successfully lost weight, with special emphasis upon methods applied and background factors,
is of major importance. Many people are successful in losing weight by
themselves without taking part in any organized group activity. The
knowledge about their success and the methods applied does not usually
reach the health care personnel and is one reason why it is difficult
to get reliable information about those who are successful in losing
weight.
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MedicalResearch.com Interview with:
Harold P. Erickson Ph.D.
James B. Duke Professor, Department of Cell Biology
Duke Univ. Med. Center Durham, NC 27710
MedicalResearch: What is the background for this study?Dr. Erickson: In Jan 2012 a paper reported the discovery of irisin, a hormone reportedly lopped off a precursor in muscle and sent through the bloodstream to fat tissue, where it turned white fat into brown fat. Brown fat burns calories, and is what hibernating animals – and even human babies -- use to keep warm. Turning on brown fat had exciting promise for obesity, diabetes, etc. Dozens of labs around the world jumped on the discovery and started trials in animals and humans of how irisin levels in blood were altered by exercise and a variety of metabolic challenges.
MedicalResearch: What are the main findings? Early reports.Dr. Erickson: The follow-up studies from different labs reported a huge range of values for the level of irisin in blood, so they could not all be right. And most of them failed to find any significant effect of exercise. In 2013 two papers criticized the irisin study. A commentary article by Harold Erickson (Adipocyte 2:289-93) reported two substantial flaws in the original study. A research paper by S. Raschke, J. Eckel and colleagues (PloS one 8:e73680) concluded that humans did not make significant amount of irisin. The human gene for irisin has a deleterious mutation in the start codon, and Raschke et al showed that this reduced irisin expression to only 1% the level with the normal start. These two reports may have slowed new labs entering the field, but many groups already invested continued to publish. (more…)
MedicalResearch.com Interview with:
Elizabeth M. Widen, PhD, RD
Postdoctoral Fellow in the Institute of Human Nutrition & Department of Epidemiology
Columbia University
Mailman School...
MedicalResearch.com Interview with:
Elizabeth A. Lawson, M.D., M.M.Sc.
Assistant Professor of Medicine
Harvard Medical School
Director, Interdisciplinary Oxytocin Research Program
Neuroendocrine Unit Massachusetts General Hospital
Boston, MA 02114
Medical Research: What is the background for this study? What are the main findings?
Response: Oxytocin is a hormone produced in the brain that has been shown to reduce food intake in animal studies. The role of oxytocin on appetite and food consumption in humans is not well understood. We therefore performed a randomized, placebo controlled cross-over study of single dose administration of intranasal oxytocin (Syntocinon, Novartis) in healthy men. Subjects presented fasting in the early morning and were randomized to receive 24 IU intranasal oxytocin or placebo. They selected breakfast from a menu and were offered double portions. The caloric content of the food they ate was calculated. They returned for a second visit, which was the same except for this time, they received the other treatment (placebo or oxytocin). There was no difference in how much food the men reported eating in the three days leading up to each of the study visits. On average, the men ate 122 fewer calories and about 9 grams less fat after receiving oxytocin compared to placebo. There was also evidence that oxytocin resulted in greater use of fat as a fuel for the body, and improved insulin sensitivity.
(more…)
MedicalResearch.com Interview with:
Professor Dr. Bernd Weber
Heisenberg Professor
Department of Epileptology
Head - NeuroCognition | Imaging
Life&Brain Center Board of Directors
Center for Economics and Neuroscience Bonn
(more…)
MedicalResearch.com Interview with:
Margaret C. Campbell, Phd | Professor | Marketing
Chair, Doctoral Curriculum Program Committee
437 Leeds School of Business
University of Colorado at Boulder
Boulder, CO 80309-0419
Medical Research: What is the background for this study? What are the main findings?
Dr. Campbell: People try to maintain healthy body weights, attain academic and career success, save money for a car, a house, or retirement, and achieve a host of other goals that require repeated, goal-consistent behaviors. Unfortunately, consumers’ efforts often fall short. For example, 68% of Americans are overweight (Weight Control Information Network 2010), 46% who begin college do not graduate within six years (Associated Press 2006), and although 93% say that saving for retirement is important, only about 60% are actually saving (TIAA-CREF 2010) and approximately 50% have accumulated less than $25,000 (Helman, VanDehrei and Copeland 2007). Understanding goal pursuit and consumers’ choices to continue effort toward a goal that requires repeated goal-consistent behaviors is thus important. People need to be able to make progress on important goals that substantially impact their quality of life.
Monitoring the influence of behavior on distance from a focal goal has been identified as important for successful goal pursuit - such as weight loss. In seven experiments, we find that people tend to have a “progress bias” such that they perceive that goal-consistent behaviors (such as avoiding eating a piece of cake) help progress more than equivalent-sized goal-inconsistent behaviors (such as eating a piece of cake) hurt progress. An experiment on exercise and eating shows that the progress bias can lead to poor understanding of progress and thus, premature release of the goal. In this study, the progress bias resulted in people with a goal of expending more calories than they consumed ended up consuming more than they expended.
(more…)
MedicalResearch.com Interview with:
Frances M. Sladek, Ph.D.
Professor of Cell Biology and Toxicologist
Associate Director, UCR Stem Cell Center
Department of Cell Biology and Neuroscience
University of California
Riverside, CA 92521-0314
Medical Research: What is the background for this study? What are the main findings?
Dr. Sladek: In 2011 Blasbalg et al reported in the American Journal of Clinical Nutrition that the consumption of soybean oil was the component of the American diet that had changed the most since the early 1900s. It had in fact increased 1000-fold. Soybean oil is currently not only the main type of vegetable oil used in the U.S. but soybean meal is a major component of the diet of the animals such as cows and pigs, resulting in changes in the fatty acid composition of animal fat. Soybean oil is also increasingly being used worldwide: 40 million tons were produced in 2007 alone.
In our previous study we found that a high fat diet containing comparable amounts of soybean oil to what Americans are currently consuming caused mice to become obese, diabetic and insulin resistant and to have large lipid droplets and hepatocyte ballooning in their livers.
Others had found similar results and proposed that linoleic acid (an omega 6 polyunsaturated fat) that makes up >55% of the oil was responsible for the negative metabolic effects.
DuPont recently generated a genetically modified soybean oil that had reduced levels of linoleic acid and hence less of a tendency to generate trans fats. This oil (called Plenish) came onto the market for the first time in 2014. The fatty acid composition of Plenish is similar to that of olive oil (low linoleic acid and high oleic acid), which is a major component of the healthy Mediterranean diet. The implication, therefore, is that Plenish is healthier than conventional soybean oil but that has not been formally proven.
In the current study, we found that while a high fat diet containing Plenish also induced obesity, glucose intolerance and fatty liver, it did not induce insulin resistance as did the conventional soybean oil. It also induced somewhat less fat accumulation.
Finally, we compared the diet enriched in soybean oil to an isocaloric diet that contained the same amount of total fat (40%kcal, Americans consume 34-37% fat) but with 90% of the fat from coconut oil. Those animals gained very little weight (13% versus 38% with the conventional soybean oil and 30% with the Plenish) and were not diabetic or insulin resistant. Their livers also had less fat than either of the two soybean oil diets and showed no signs of hepatocyte ballooning. Coconut oil has essentially no linoleic acid or other PUFAs.
Our results, assuming humans respond in the same way as mice, suggest that people should avoid the consumption of too much soybean oil, either conventional or Plenish. They also show that coconut oil, which is made up of saturated fats (primarily medium chain triglycerides), is much healthier for you than soybean oil. Coconut oil has been noted previously for its beneficial health effects. (more…)
MedicalResearch.com Interview withChristopher C. Imes, PhD, RN
Assistant Professor, Acute and Tertiary Care
University of Pittsburgh, School of Nursing
MedicalResearch: What is the background for this study? Dr. Imes: Increased physical activity (PA) with reduced energy intake is the key strategy to achieve weight loss. However, in research, there are challenges to obtaining accurate PA data. Many studies rely on self-report, which is easily accessible and inexpensive but is known to have numerous limitations. Pedometers are a relatively inexpensive and accessible method to objectively measure certain aspects of physical activity. The purpose of this analysis was to examine the associations between self-reported physical activity, pedometer step count data and weight loss during the first 6-months of the Self-Efficacy Lifestyle Focus (SELF) trial. All participants in this trial were instructed to reduce their calorie and fat intake, were encouraged to engage in at least 150 minutes of moderately intense PA/week or 7500 steps/day, and to self-monitor their diet and physical activity.
MedicalResearch: What are the main findings?Dr. Imes: Change in self-reported physical activity from baseline to 6 months was not associated with weight change. However, average daily step count, derived from pedometers given to participants during the same time period, was associated with weight loss. More daily steps results in more weight loss. The participants who averaged over 7500 steps/day lost about 9.5% of their initial body weight; whereas, the participants who averaged less than 5000 steps/day only lost about 5.0%.
(more…)
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