The skinny on why some battle the bulge

TULANE (US)—In an effort to learn why some people struggle with obesity and others don’t, researchers at Tulane University are taking a closer look at a recently discovered endocrine system that has a role in regulating appetite.

The study aims to characterize the genetic relationships between race, gender, and obesity, according to Tina Thethi, assistant professor of endocrinology and principal investigator.

“There is some preliminary data that obesity and the endocannabinoid system is different among ethnic groups,” explains Vivian Fonseca, who holds the Tullis-Tulane Alumni Chair in Diabetes at Tulane University. “Our varied population in New Orleans, with a lot of obesity, gives us a unique opportunity to study this.”

Thethi and her colleagues are currently recruiting residents of New Orleans and surrounding parishes to participate in the study. “The study kicked off in July 2008 and we will continue to recruit participants until we have seen 700,” Thethi says.

“We’re looking at two of the hormones that we know are high in people who are obese and actually stimulate food intake, and we’re looking at that part of the gene that is supposed to turn off these hormones,” says Thethi. “The main purpose in doing the study is to characterize the differences between men and women and African Americans and Caucasians, because I’m not sure we know the differences between these groups.”

The study team is recruiting an equal number of men and women and equal numbers of African Americans and Caucasians. In addition, the researchers established a control group comprised of people with a body mass index of less than 27, which will be compared with an obese group that includes people with a body mass index of more than 30.

The researchers are looking in particular at the workings of two hormones called anandamide and 2-arachidonoyl-glycerol.

“These endocannabinoids are hormones that actually stimulate food intake,” says Thethi. “There has been data showing that these hormones exist in different levels among people who are obese versus lean. So, if a person has a higher level of these hormones, a person would be eating more and would be more likely to be obese.”

The study is funded by the Tulane Research Enhancement fund.

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