Do depressive symptoms increase the risk for the onset of coronary disease? A systematic quantitative review.

OBJECTIVE: The objectives of this study were to systematically review the recent studies of the contribution of depression to the onset of coronary disease and to estimate the magnitude of the risk posed by depression for onset of coronary disease.
METHOD: We searched MEDLINE (1966-2000), PsychInfo (1967-2000), and cross references and conducted informal searches for all community studies of depression symptoms in samples with no clinically apparent heart disease at baseline. From these studies we selected all published cohort studies of 4 years or more follow-up that controlled for other major coronary disease risk factors and reported relative risks (or a comparable measure) of baseline depression for the onset of coronary disease. Following methods for the meta-analysis of epidemiologic studies, we used a random-effects model to estimate the combined overall relative risk.
RESULTS: Ten studies met our inclusion criteria. Relative risks ranged from 0.98 to 3.5. Nine studies reported significantly increased risk, including two with mixed results; one study reported no increased risk. The combined overall relative risk of depression for the onset of coronary disease was 1.64 (95% CI = 1.41-1.90).
CONCLUSIONS: This quantitative review suggests that depressive symptoms contribute a significant independent risk for the onset of coronary disease, a risk (1.64) that is greater than the risk conferred by passive smoking (1.25) but less than the risk conferred by active smoking (2.5). Future prospective community studies should examine the effect of severity and duration of depressive symptoms and disorders on the risk for the onset of coronary disease.