Abstract

Objective: To investigate the association between thyroid-stimulating hormone (TSH) levels and depression in older adults.

Design: Prospective cohort study with an 11-year follow-up period.

Setting: Community-dwelling participants from the ASPirin in Reducing Events in the Elderly (ASPREE) randomized controlled trial and its follow-up observational study in Australia.

Participants: About 9,050 adults aged ≥70 years with baseline TSH measurements and depression assessments. Participants with thyroid cancer, baseline depression, or thyroid-altering medications were excluded.

Measurements: Depression was assessed annually using the Center for Epidemiological Studies Depression Scale (CES-D-10) using a cut score of 12, and hospital admission records. TSH was measured at baseline and year 3, categorized as low (<0.34 mU/L), normal (0.34-3.75 mU/L), or high (>3.75 mU/L).

Results: Cross-sectional analyses found no significant association between TSH levels and depression at baseline (p = 0.79) or year 3 (p = 0.054). Longitudinal analyses revealed no relationship between baseline or time-varying TSH levels and incident depression over the follow-up period (HR = 1.0, 95% CI: 0.96-1.05).

Conclusions: TSH levels are not associated with prevalent or incident depression in older community-dwelling adults. These findings should guide screening approaches for depression in older adults.