Depression and its association with diabetes, cardiovascular disease, and birth weight

Background. Diabetes increases the risk for depression. Aim. To study the independent effects of diabetes mellitus (DM) and cardiovascular disease (CVD) on the prevalence of depression and to examine low birth weight as a possible common explanatory factor. Methods. 2003 subjects from the Helsinki Birth Cohort Study underwent a 75-g oral glucose tolerance test and filled out the Beck Depression Inventory. Results. Depressive symptoms were more prevalent among subjects with diabetes (23.5%) than among those with normal glucose tolerance (16.6%) (P < 0.001). A history of CVD also markedly increased the odds of having depressive symptoms (odds ratio (OR) =2.38, 95% confidence interval (CI) = 1.70-3.32, P < 0.001). The association between DM and depressive symptoms was, however, rendered non-significant when adjusting for the presence of CVD. Being born with a low birth weight doubled the risk for having depressive symptoms (OR=2.64, 95% CI=1.42-4.91, P=0.002) and magnified the association between CVD/DM and depression. Conclusion. Diabetes has only a minor independent effect on concurrent occurrence of depressive symptoms, while cardiovascular disease seems to be a more important underlying factor. The association between disease and depression is in particular characteristic to individuals born with a low birth weight.