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.