Association between statin use and depressive symptoms in a large community-dwelling older population living in Australia and the USA: a cross-sectional study

Background: Statin use has been frequently associated with depressive symptoms in an older population. However, the nature of this association is uncertain in the literature. In this study, we aimed to investigate the association of statin intake and the prevalence of depressive symptoms in healthy community-dwelling older adults living in Australia and the USA.

Methods: We analysed baseline data from 19,114 participants, over 70 years of age (over 65 years of age, if from an ethnic minority). The association of self-reported statin use and prevalence of depressive symptoms, as measured by a validated depression scale [Center for Epidemiological Studies Depression Scale (CES-D 10)], was determined using logistic regression models. Multivariable logistic models were implemented to account for important demographics and other lifestyle and socioeconomic factors, such as sex, age, living status, education and smoking history.

Results: A total of 5987 individuals were statin users. Of those, 633 (10.6%) had depressive symptoms (CES-D 10 cut-off ≥ 8), compared with 1246 (9.5%) of the non-statin users. In the unadjusted model, statin use was associated with an increase in prevalence of depressive symptoms (odds ratio 1.13, confidence interval 1.02-1.25, p = 0.02). However, after adjusting for important demographic and socioeconomic factors, the use of statins was not significantly associated with depressive symptoms (odds ratio 1.09, confidence interval 0.98-1.20, p= 0.11). In secondary analyses, only simvastatin was marginally associated with an increased prevalence of depressive symptoms. Statins were associated with a decreased prevalence of depressive symptoms in individuals with severe obesity (body mass index > 35 kg/m²) and an increased prevalence in participants between 75 and 84 years of age.

Conclusion: This study in a large community-dwelling older population did not show any association of statins with late-life depressive symptoms, after accounting for important socioeconomic and demographic factors. Confounding by indication is an important issue to be addressed in future pharmacoepidemiologic studies of statins.