Depressive symptoms result in an increase in abdominal fat, independent of overall obesity. A report published in the December edition of Archives of General Psychiatry, has put forward a notion that specific mechanisms link depression with fat accumulation around the abdomen. This could explain why depression is associated with an increased risk of diabetes and heart disease.
It is estimated that up to 15 percent of the older population have depressive symptoms. Relatively little is know about the underlying mechanisms that seem to connect depression with diseases such as diabetes or cardiovascular disease. Various disturbances of the neuroendocrine system, such as elevated cortisol levels and low sex-steroid hormones, have been found in people with depression. This combination is argued to be partly responsible for fat accumulation around the viscera (abdominal region). Until now, no large study has tested the idea that depressive symptoms lead to an increase in visceral fat, independent of overall obesity.
Nicole Vogelzangs, of the VU University Medical Center, Amsterdam, the Netherlands, and colleagues, reviewed data from 2088 well-functioning white and black people in the 70-79 age category, tracked for a period of five years.
The analysis of findings showed that depression was, "specifically associated with abdominal obesity [and] independent of overall obesity." Even across the whole range of weight change, "an association existed between depression and visceral fat, suggesting that even in persons who lost weight, visceral fat was preferentially retained in those with depression."(p.1391).
Curiously, the link between depression and visceral fat did not appear in black women. The reasons for this are not clear but the authors note that the black women in the sample experienced a relatively large decrease in visceral fat, which may have obscured the association.
As to the mechanism by which depression may promote fat accumulation around the abdomen, the authors point out that visceral fat is highly sensitive to cortisol, which activates fat production. The idea that depressed people have unhealthier lifestyles was also taken into account. However, even adjusting for smoking, alcohol, lack of exercise and poor diet, the expectation would be for an increase in overall and abdominal obesity. This, plus the fact that some antidepressants are known to promote weight gain, were all accounted for within the scope of the investigation.
Further research is now needed to determine the specific role for each component in the overall mechanism of visceral fat production. In so doing, it is hoped to provide useful insights into potential treatments for depression-related consequences.
Vogelzangs, N., Kritchevsky, S.B., Beekman, A.T.F (et al) (2008) Depressive Symptoms and Change in Abdominal Obesity in Older Persons. Archives of General Psychiatry. 65. 12, 1386-1393.