Among a large group of German men ages 45 to 74, obese men had significantly higher concentrations of a protein called CRP compared with non-obese men. CRP serves as a signal of artery inflammation and high levels of the protein may be a good predictor of future heart disease.
And depression seems to add to obese men's heart woes: CRP levels were higher in the most depressed obese men than in the less depressed obese men, according to Karl-Heinz Ladwig, Ph.D., of the GSF National Research Center for Environment and Health and colleagues.
Depression did not affect CRP levels among non-obese men, however, suggesting that a combination of obesity and depression may be more risky for some men.
"We cannot provide a convincing explanation why the association between CRP and depression was much stronger in obese than in non-obese participants. However, it may be that both conditions -- obesity and depression -- share a common ground which, in consequence, makes depressed, obese subjects in particular susceptible for coronary heart disease," Ladwig says.
The association between obesity and depression remained strong even after accounting for other factors that can affect CRP levels, including smoking, alcohol consumption and physical activity, according to the researchers.
Twenty-three percent of the 3,205 men included in the study were identified as obese. On the whole, the group of obese men was not any more depressed than the non-obese group, Ladwig says.