Genetic Markers for Obesity Confirmed

Newswise — Tulane University researchers have confirmed several genes that determine the inheritance of obesity. This is the first study of longitudinal data to link body mass measurements taken over several decades to specific genes located on chromosomes. The researchers analyzed blood and health data from white siblings in 342 families who had been screened multiple times in the Bogalusa Heart Study over the past 30 years.

Obesity, a leading risk factor for heart disease and diabetes, is reaching epidemic proportions in the United States. Although the causes of obesity are complex, researchers estimate that between 40 and 70 percent of obesity cases have a genetic component. Over the past 20 years, scientists have identified more than 250 genes or chromosome regions that may contribute to obesity.

"Obesity in America is a complex trait and its development depends on several genes as well as a person's interactions with environmental factors such as diet and exercise," says researcher Wei Chen. "We found evidence of obesity-related genes on chromosomes 1, 5, 7, 12, 13 and 18 that were linked to long-term trend of obesity from childhood to adulthood, and the gene on chromosome 12 showed the strongest link."

Chen is an epidemiologist at the Tulane University School of Public Health and Tropical Medicine.

A particulargene on chromosome 12 is related to the development of insulin resistance. Insulin resistance is a reduced sensitivity in the tissues of the body to the action of insulin, a hormone that allows blood sugar to enter tissues to be used as a source of energy. Insulin resistance is associated with type 2 diabetes, high blood pressure and obesity.

The study results appear in the April issue of the International Journal of Obesity.

The journal is available on-line at: http://www.nature.com/cgi-taf/DynaPage.taf?file=/ijo/journal/v28/n4/full/0802610a.html

The Bogalusa Heart Study is the longest running, biracial, community-based study of heart disease risk factors beginning in childhood in the world. Since its inception in 1973, cardiologist Gerald Berenson and his team have screened over 16,000 adults and children in the Bogalusa, La. area in an effort to understand heart disease risk factors over the lifespan. Children who began the study in the 70s while they were in elementary school are now adults who continue to participate in the screening process. Moving from a primarily pediatric study, now the investigators are studying aging. Funding for the research comes from the National Institutes on Aging and Heart, Lung and Blood of the National Institutes of Health.