Prospective longitudinal study of testosterone and incident depression in older men: the Health In Men Study

Background: Depression in older men has been associated with low circulating testosterone concentration but data from prospective studies are limited. Methods: We conducted a prospective longitudinal study in a community representative cohort of 3179 older men free of clinically significant depressive symptoms at baseline. The main objective of this study was to determine if low serum testosterone, dihydrotestosterone and estradiol concentrations are associated with the development of depressive symptoms. Incident depression was assessed with the Patient Health Questionnaire and via an electronic health record database (The West Australian Data Linkage System). The main exposures of interest were serum testosterone, dihydrotestosterone and estradiol measured by liquid chromatography-mass spectrometry and calculated free testosterone in baseline blood samples (collected between 2001 and 2004). Results: One hundred and thirty five men (4.2%) developed depression over a median follow up time of 9.4 years (range 8.4-10.9). Men with incident depression were older (median age 77.7 vs 76.1 years, z=-3.82, p=0<0.001) and were more likely to have cardiovascular disease (43.0% vs 32.6%, χ2=6.32, p=0.012) and diabetes (22.2% vs 13.2%, χ2=8.95, p=0.003). Low serum total testosterone (