Overweight and Obese Young Adults at Decreased Risk of Acne

MedicalResearch.com Interview with:
Igor Snast, MD
Department of Dermatology
Rabin Medical Center–Beilinson Hospital
Israel

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Acne is the most common skin disorder among adolescents. Obesity has been suggested to promote acne, however various studies evaluating the relationship between obesity and acne have yielded contradictory outcomes.

Our population-based study demonstrates that overweight, obese and severely obese youths have decreased odds of having acne (20%, 35% and 50% respectively) compared to normal-weight subjects. Continue reading

Oxytocin Reduces Activation of Brain Areas Linked to Stimulation by High Calorie Food Images

MedicalResearch.com Interview with:

Liya Kerem, MDFellow, Pediatric Endocrine UnitMassachusetts General Hospital for ChildrenHarvard Medical School

Dr. Kerem

Liya Kerem, MD
Fellow, Pediatric Endocrine Unit
Massachusetts General Hospital for Children
Harvard Medical School

MedicalResearch.com: What is the background for this study?  

Response: The hypothalamic neurohormone Oxytocin (OXT), shown to decrease food intake in animals and humans, is a promising novel treatment for obesity. We previously showed that in men with overweight/obesity, intranasal (IN)OXT reduced the fMRI activation in the ventral tegmental area (VTA), the origin of the mesolimbic dopaminergic reward system, in response to high-calorie food vs non-food visual stimuli.

Here, we employed fMRI functional connectivity analysis, which better characterizes the exchange in information between neural systems in a context-dependent manner. We hypothesized that Oxytocin would reduce the functional connectivity of the VTA with food motivation brain areas in response to high-calorie foods.  Continue reading

Is Behavioral Change Among Overweight Diabetics Feasible and Sustainable?

MedicalResearch.com Interview with:
Giuseppe Pugliese, MD, PhD
for the Italian Diabetes and Exercise Study 2 (IDES_2) Investigators
Department of Clinical and Molecular Medicine
‘‘La Sapienza’’ University
Diabetes Unit, Sant’Andrea University Hospital
Rome, Italy

MedicalResearch.com: What is the background for this study?

Response: There is a growing epidemic of obesity and type 2 diabetes worldwide,
which are causally related to the increasing prevalence of “physical
inactivity”, i.e., an insufficient amount of moderate-to-vigorous
physical activity according to current guidelines, and
“sedentariness”, i.e., too many hours, especially if uninterrupted,
spent in a sitting or reclined position.  These two unhealthy
behaviors exert their detrimental effects independently of each other
and are very common among people suffering from type 2 diabetes, who
would therefore benefit from increasing physical activity and reducing
sedentary time, as recommended by current guidelines.

However, such a behavior change is generally difficult for a number of
internal and external barriers and requires behavioral interventions
targeting both physical activity and sedentary habits.  Unfortunately,
there is no definitive evidence that this is indeed feasible and,
particularly, that, if adopted, change in behavior can be maintained
in the long term.  Continue reading

Obesity Threat to Health of Individuals and Populations May Be Underestimated

MedicalResearch.com Interview with:

Ching-Ti Liu, PhD Department of Biostatistics Boston University School of Public Health Boston, Massachusetts

Dr. Liu

Ching-Ti Liu, PhD
Department of Biostatistics
Boston University School of Public Health
Boston, Massachusetts

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Being overweight and obese are increasing worldwide and this obesity epidemic threatens to reverse the gains in life expectancy achieved over the past century. However, many investigators have observed, paradoxically, that overweight individuals are associated with a lower mortality risk. These results may suffer from a potential confounding due to illness or reverse causality in which preexisting conditions may alter both body weight and the risk of death.  Recently published studies have tried to mitigate this reverse causal bias by implementing sample exclusion and they came to a different conclusion: between BMI and all-cause mortality there is an increased risk of death for the entire range of weights that are in the overweight and obesity ranges.

However, the elimination strategies may lead to the loss of generalizability or precision due to over-adjustment. In addition, the traditional investigations have only utilized a subject’s weight at a single point in time, which makes it difficult to adequately address bias associated with reverse causality.

Currently, the idea incorporating a subject’s weight history has been proposed to deal with the concern of reverse causality, but the existing works had been based on a subject’s recall or self-reported data, which may lead to misclassification and, therefore, result in overestimating the risk of mortality.

To help assess the relevance of being overweight or obese to the risk of death in the general population, we conducted a prospective study, using an individuals’ maximum BMI before the beginning of survival follow-up instead of their weight status at a single point in time, using data from the Framingham Heart Study (FHS).

We observed increasing risk of mortality across various BMI categories (overweight < obese I < obese II) relative to normal weight using maximum BMI over 24 years of weight history.

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Brain Reward System Underactive In Some Overweight People

Dr. Agatha van der Klaauw, PhD Wellcome Trust Postdoctoral Clinical Fellow Wellcome Trust-MRC Institute of Metabolic Science University of Cambridge Metabolic Research Laboratories Addenbrooke's Hospital Cambridge, United KingdomMedicalResearch.com Interview with:
Dr. Agatha van der Klaauw, PhD
Wellcome Trust Postdoctoral Clinical Fellow
Wellcome Trust-MRC Institute of Metabolic Science
University of Cambridge Metabolic Research Laboratories
Addenbrooke’s Hospital
Cambridge, United Kingdom

 

Medical Research: What are the main findings of the study?

Dr. van der Klaauw: Obesity occurs when we eat more calories than we burn which is often easy to do as many foods are highly palatable and high in calories. Highly palatable foods such as chocolate trigger signals in the brain that give a feeling of pleasure and reward (sometimes called cravings) which can contribute to overeating. These signals are processed in the reward centres in the brain, where sets of neurons release chemicals such as dopamine. However, very little is known about whether the reward centres of the brain work differently in some people who are overweight.

In this study, we were interested in studying overweight people who had a problem with the melanocortin 4 receptor (MC4R) gene. About 1% of obese people have a problem in this gene which contributes to weight gain from a young age. We compared three groups of people: people who were overweight due to a problem in the MC4R gene, people who were overweight but the gene was normal and some people who were normal weight. We performed functional Magnetic Resonance Imaging (fMRI) scans to look at how the reward centres in the brain were activated by pictures of appetizing food such as chocolate cake compared to bland food such as rice or broccoli and non-food items such as staplers.

We found that in normal weight people, the reward centres are activated (light up) when they are shown pictures of cake or chocolate and the same was seen in overweight people with a problem in the MC4R gene. But we found that the reward centres were underactive in overweight volunteers (in whom the gene was normal).

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