Depressive Symptoms Are Not Associated with Leukocyte Telomere Length: Findings from the Nova Scotia Health Survey (NSHS95), a Population-Based Study

Background: Premature shortening of leukocyte telomere length has been proposed as a novel mechanism by which depression may confer increased risk of adverse cardiovascular events. Prior studies demonstrating associations of depression and depressive symptoms with shorter leukocyte telomere length were small, included selected psychiatric outpatients, were based on convenience samples, and/or adjusted for a limited number of possible confounding factors. Methods and Findings: We examined the associations of depressive symptoms, probable depressive disorder, and specific depressive symptom clusters, as assessed by the Center for Epidemiological Studies-Depression (CES-D) scale, with leukocyte telomere length, measured by using a real-time PCR method, in 2,225 apparently healthy participants from the 1995 Nova Scotia Health Survey population-based study. The mean age was 48.2 +/- 18.9 years; 49.9% of participants were female; and the mean CES-D score was 7.4 +/- 7.9. The mean telomere length was 5,301 +/- 587 base pairs. In an unadjusted model, depressive symptoms were significantly associated with longer leukocyte telomere length (B = 27.6 base pairs per standard deviation increase in CES-D, 95% confidence interval [CI] = 3.1-52.1, p = 0.027). This association was no longer significant after adjustment for age and sex (B = 9.5, 95% CI = -14.6-33.6, p = 0.44) or after further adjustment for body mass index, Framingham risk score and previous history of ischemic heart disease (all p's >= 0.37). Neither probable depressive disorder nor specific depressive symptom clusters were independently associated with leukocyte telomere length. Conclusions: Concurrent depressive symptoms were not associated with leukocyte telomere length in a large, representative, population-based study.