THE ASSOCIATION OF THYROID STIMULATING HORMONE LEVELS WITH COGNITIVE FUNCTION AND DEPRESSED MOOD: THE RANCHO BERNARDO STUDY

Objective: To evaluate the association of thyroid stimulating hormone levels with cognitive function and depressed mood in a community-based sample. Design: Cross-sectional study. Setting: Clinic visit in 1999- 2003. Participants: Community-dwelling men (N=447) and women (N=663) aged 42-99 years. Measurement: Cognitive function was assessed with the Buschke-Fuld Selective Reminding Test, the Modified Mini-Mental State Examination, Trails B, and category fluency. Depressed mood was assessed with the Beck Depression Inventory (BDI). A fasting blood sample was obtained for thyroid stimulating hormone (TSH) measurement. Results: Mean age was 73.6±10.0 in men and 74.3±10.4 in women. Mean TSH was 1.9 μIU/ml in both sexes; 9.0% of men and 24% of women reported thyroid medication use. Mean BDI scores were 4.6±4.1 in men and 5.2±4.3 in women; 9% of men and 11% of women used antidepressants. Before and after adjustment for covariates or exclusion of participants taking thyroid hormones, no associations were observed between TSH and cognitive function (ps>0.10). TSH was inversely associated with BDI (p=0.03) in men, but not women. Conclusions: Thyroid stimulating hormone level was unrelated to cognitive function in men and women, and was inversely associated with depressed mood in men only, possibly reflecting the greater use of both thyroid medications and antidepressants by women.