News Brief: August 2009

 Arlyn G. Riskind
Director, Media Relations
Phone: (301) 941-0240
Email: ariskind@endo-society.org

Aaron Lohr
Manager, Media Relations
Phone: (240) 482-1380
Email: alohr@endo-society.org

1.   Weight-Loss Surgery Can Break a Family’s Cycle of Obesity
2.   Exercise Alone Shown to Improve Insulin Sensitivity in Obese Sedentary Adolescents
3.   New Patient Fact Sheet on Endocrine Effects of Bariatric Surgery Available


1. Weight-Loss Surgery Can Break a Family’s Cycle of Obesity

New study finds the intrauterine environment may determine whether a child is destined to become obese.

Adolescent and young children of obese mothers who underwent weight-loss surgery prior to pregnancy have been found to have a lower prevalence of obesity and significantly improved cardio-metabolic markers when compared to siblings born before the same obese mothers had weight-loss surgery. This new study has been accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).

Obesity can lead to insulin resistance, cardiovascular disease and pregnancy complications and is a major contributor to causes of death in industrialized nations. Previous studies of obese pregnant women have shown that obesity and its co-morbidities can be transmitted to their children, which indicates that the intrauterine environment may determine whether a child at birth is already destined to become obese.

“Our study confirms previous research showing that the intrauterine environment may be more important than genes and the post-natal environment when it comes to the association between maternal obesity and childhood obesity,” said John Kral, MD, PhD, of SUNY Downstate Medical Center in Brooklyn, N.Y. and co-author of the study. “Any medical or surgical treatment to reduce obesity and existing metabolic disorders before pregnancy can be an investment in the life of future offspring.”

Weight-loss surgery limits the amount of food a person can consume. Some of these operations also restrict the amount of food that can be digested. This particular study focused on women who had undergone biliopancreatic diversion (BPD) prior to becoming pregnant. BPD changes the normal process of digestion by making the stomach smaller and directing food to bypass part of the small intestine resulting in fewer calorie absorption.

Specifically, researchers studied 49 mothers who had undergone BPD surgery and their
111 children (between the ages of 2.5 and 25 years). All mothers in this study had children born before and then after their weight-loss surgery. The research found that children who were born after their mother underwent weight-loss surgery had reduced birth weight and waist circumference and were three times less likely to become severely obese. Furthermore, children born after their mother’s weight-loss surgery had improved cardiovascular markers including reduced insulin resistance and lower cholesterol.

“To our knowledge, our paper is the first to demonstrate that dramatic maternal weight loss causes metabolic improvements in their children,” said Kral. “Our findings show that obese women should be encouraged to lose weight before becoming pregnant, and then, once pregnant, should limit their weight gain. For those women interested in both surgical treatment and having children, we believe surgery should come first. Preventing obesity and treating it effectively in young women could prevent further transmission to future generations.”

Other researchers working on the study include J. Smith, K. Cianflone, S. Simard and Picard Marceau of the Centre de Recherche Institut Universitaire de Cardiologie et Pneumologie de Quebec in Canada; S. Biron, S. Lebel, S. Marceau, O. Lescelleur and L. Biertho of Laval University in Quebec, Canada; and J.G. Kral of SUNY Downstate Medical Center in Brooklyn, N.Y.
 
The article, “Effects of maternal surgical weight loss on intergenerational transmission of obesity,” will appear in the November 2009 issue of JCEM.

2. Exercise Alone Shown to Improve Insulin Sensitivity in Obese Sedentary Adolescents

New study isolates impact of exercise from diet and weight loss interventions.

A moderate aerobic exercise program, without weight loss, can improve insulin sensitivity in both lean and obese sedentary adolescents, according to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM). Insulin is a hormone produced in the pancreas that permits glucose to enter cells to be used for energy or stored for future use by the body.

Because obese adolescents are resistant to insulin, in order to maintain normal blood sugar levels, they have to increase their production of insulin. Increased insulin production however, places higher demands on the pancreas. These higher demands can exhaust pancreatic beta cells to the point that they no longer produce sufficient amounts of insulin to keep blood sugar levels normal, which might subsequently lead to type 2 diabetes.

“Because weight loss can be difficult to achieve and maintain in obese sedentary children, the purpose of this study was to determine whether a controlled exercise program, without any diet intervention and with no intention of weight loss, would improve fat distribution and sensitivity to insulin,” said Agneta Sunehag, MD, PhD, of Baylor College of Medicine and senior author of the study. “We found that a 12-week moderate aerobic exercise program consisting of four
30-minute workouts a week increased fitness and improved insulin sensitivity in both lean and obese adolescents.”

In this study, 29 adolescents (14 lean and 15 obese) completed the 12-week moderate aerobic exercise program. During the exercise sessions, subjects worked out on a treadmill, elliptical or bicycle. The goal of each exercise session was to get the participants’ heart rate to increase to at least 70 percent of their maximum capacity. Glucose and insulin concentrations were measured both before and after the exercise program. Cardiovascular fitness was determined using an oxygen consumption test which consists of measuring oxygen uptake of the participant during a treadmill exercise where speed and incline is increased every three minutes until the subject reaches his maximum exercise capacity.

“Many studies include both diet and exercise interventions, which makes it difficult to determine which intervention is most effective and best accepted by adolescents,” said Sunehag. “Our findings show that exercise alone can increase fitness and improve insulin sensitivity, making an aerobic program like the one used in this study a potential useful tool in preventing obesity-related illnesses.”

Other researchers working on the study include Gert-Jan van der Heijden of Baylor College of Medicine in Houston, Tex.; Gianna Toffolo and Erica Manesso of the University of Padova in Padua, Italy; and Pieter Sauer of the University of Groningen in The Netherlands.
 
The article, “Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents,” will appear in the November 2009 issue of JCEM.

3. New Patient Fact Sheet on Endocrine Effects of Bariatric Surgery Available

The Hormone Foundation has published a new bilingual (English/Spanish) patient fact sheet, Bariatric Surgery and the Endocrine System: Benefits and Risks. The fact sheet describes common types of bariatric surgery and the potential endocrine-related benefits of the operation and resulting weight loss, including improvement or resolution of type 2 diabetes, improved lipid profile, and reduced effects of polycystic ovary syndrome. It also cautions that malabsorptive operations could lead to nutritional deficiencies and related complications without proper nutrition and life-long supplement use. For more information visit: www.hormone.org.