Scientists have uncovered a link between higher levels of a stress hormone and obesity in adolescent girls, but not boys. Even though boys and girls both release the hormone during stress, the findings show that girls are most likely to become obese from higher levels of cortisol.
Cortisol, a hormone released by the adrenal gland is known to contribute to obesity, diabetes, high blood pressure, and heart disease. It can also destroy immunity. Though researchers have known that cortisol contributes to weight gain and obesity but the exact reasons are not clear. The researchers for the new study found that higher levels of the stress hormone in girls age 6 to 13 was associated with obesity.
Researchers subjected adolescent boys and girls to testing designed to raise their stress levels and then measured cortisol levels in their saliva. The study included 111 boys and girls ages 8 to 13 that were screened for symptoms of depression using a behavior checklist. The findings showed that depression that raises cortisol levels was associated with obesity only in the girls studied.
The scientists are not certain why stress and depression leads to obesity in adolescent girls and not boys. According to the authors it may be the combination of estrogen and eating behaviors - girls eat more in response to stress.
"This is the first time cortisol reactivity has been identified as a mediator between depressed mood and obesity in girls," said Elizabeth J. Susman, the Jean Phillips Shibley professor of biobehavioral health at Penn State. "We really haven't seen this connection in kids before, but it tells us that there are biological risk factors that are similar for obesity and depression."
The children in the study were asked to perform a math problem. They also had to make up a story and tell a story in addition to being told they would be evaluated by judges. Cortisol levels were measured before and after the tests. Higher levels of cortisol from stress was associated with obese adolescent girls but not boys. The research suggests that treating stress and depression could also treat obesity that predominantly affects adolescent girls.
Journal of Adolescent Health.