Objective: The relationship between depression and development of cancer is not well understood, with some studies finding a significant but small increase in risk for cancer among persons with depression. No studies have employed standardized interviews keyed to the diagnostic criteria for Major Depression. Our objective was to evaluate the relationship between Major Depression at baseline and new onset of cancer at follow-up.
Method: The study was based on a population-based 13-year follow-up survey of community-dwelling adults living in East Baltimore in 1981. After excluding 372 persons with a history of cancer or those whom reported their health as poor at the baseline interview, 3109 adults remained. Information on baseline depression status and cancer at follow-up was available for 2017 persons. A diagnosis of cancer was ascertained at follow-up through interview of survivors and from death certificates.
Results: There were 203 new cases of cancer among 2017 persons at risk. Neither Major Depression (relative risk (RR) = 1.0, 95% confidence interval (CI) 0.5-2.1) nor dysphoric episode (RR = 1.3, 95% CI 0.9-1.9) were significantly associated with increased risk of cancer at follow-up. However, among women with Major Depression, the risk of breast cancer was increased (adjusted RR = 3.8, 95% CI 1.0-14.2).
Conclusions: We found no overall association of depression with cancer. However, among women, Major Depression (but not dysphoric episode alone) was associated with the onset of breast cancer.