MedicalResearch.com Interview with: Dr. Yang Lin on behalf of all authors Department of Surgery, Division of Public Health Sciences Siteman Cancer Center, Washington University School of Medicine St Louis, Missouri Medical Research: What is the background for this study? What are the main findings? Dr. Lin: Overweight, obesity and associated chronic conditions are largely driving the...
MedicalResearch.com Interview with:
William S. Yancy, Jr., MD, MHSc
Research Associate
Center for Health Services Research in Primary Care
Durham, NC 27705
Associate Professor Department of Medicine
Duke University Medical Center
Medical Research: What is the background for this study? What are the main findings?
Dr. Yancy: A number of studies have compared different diet approaches for weight management with many of these finding that several different diets can result in significant weight loss. This has led many experts to advise that we should offer a choice among these diet options to our patients who are seeking to lose weight. We know that adherence is the best predictor of weight loss during dietary interventions, so the thought is that patients will adhere better to a diet that they prefer, resulting in more successful weight loss. In addition, allowing choice enhances patient autonomy, which is patient-centered and has been shown to increase treatment adherence. However, the previous studies of various diet approaches did not let people choose a diet, so we don’t actually know if letting them choose will lead to better weight loss. Our study specifically tested this assumption. We randomized participants to a condition where they were allowed to choose between 2 common weight loss diets or to a condition where they were randomly assigned to one of the diets. The 2 diets we used were a low-carbohydrate diet without calorie restriction and a low-fat diet combined with calorie restriction. Participants received counseling about the diets, and about behavioral strategies and physical activity, in 19 group sessions over the span of 12 months. They also received 6 phone calls with motivational counseling in the latter half of the program.
MedicalResearch.com Interview with: Kristina H. Lewis, MD, MPH, SM Kaiser Permanente Georgia, Center for Clinical and Outcomes Research, Atlanta Department of Population Medicine Harvard Medical School/Harvard Pilgrim Health Care Institute, Boston, Massachusetts Medical Research: What is the background for this study? Dr. Lewis: The prevalence of severe obesity (BMI ≥40 kg/m2) in the U.S. is rising. This is...
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.