Depression and C-Reactive Protein: Population-Based Health 2000 Study

Objective: To test whether depression is independently associated with elevated levels of C-reactive protein (CRP) in a large nationwide population-based sample. Methods: Depression and CRP were assessed in 6005 Finns aged > 30 years, as part of the ongoing population-based Health 2000 Study. Depression was determined by responses to the Beck's Depression Inventory (BDI-21) and by Composite International Diagnostic Interview (CIDI). Results: Higher scores on BDI-21 were related to higher CRP levels (beta = 0.12, p < .001) in men and (beta = 0.08, p < .001) in women. In men, but not in women, this relationship persisted after adjustment for a number of other known risk factors. In men, the more recent dysthymic disorder or at least moderate depressive episode defined using CIDI was related to elevated CRY levels (beta = 0.06, p = .006). Conclusions: Depressive symptoms may be partly responsible for inflammatory processes, and inflammatory processes may induce depressive symptoms in men.