FRIDAY, June 11, 2010 (HealthDay News) -- New research provides more evidence of a link between depression and extra pounds around the waist, although it's not exactly clear how they're connected.
The study raises the possibility that depression causes people to put on extra pounds around the belly. The opposite doesn't appear to be the case: researchers found that overweight people aren't more likely to become depressed than their normal-weight peers.
These findings come from researchers at the University of Alabama at Birmingham, who examined data from the Coronary Artery Risk Development in Young Adults Study (CARDIA), a 20-year longitudinal study of more than 5,100 men and women aged 18-30. (Longitudinal studies look for a link between cause and effect by observing a group of individuals at regular intervals over a long period of time).
Among other things, the researchers wanted to figure out if depressed people were more likely to have larger waist circumferences and a higher BMI, and how that changed over time.
They found that over a 15-year period, all the subjects put on some pounds, but those who were depressed gained weight faster.
"Those who started out reporting high levels of depression gained weight at a faster rate than others in the study, but starting out overweight did not lead to changes in depression," said study co-author Belinda Needham, an assistant professor of sociology, in a university press release.
Since the stress hormone cortisol is related to depression and abdominal obesity, Needham speculated that elevated levels might explain why depressed people tend to gain more belly fat.
"Our study is important because if you are interested in controlling obesity, and ultimately eliminating the risk of obesity-related diseases, then it makes sense to treat people's depression," Needham said. "It's another reason to take depression seriously and not to think about it just in terms of mental health, but to also think about the physical consequences of mental health problems."
The study appears in the June issue of the American Journal of Public Health.
To learn more about depression, head to the U.S. National Institute of Mental Health.