We examined the prospective associations between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex-hormone binding globulin (SHBG) with risk of AF (atrial fibrillation) among 1019 otherwise healthy men of average age 76.3±4.9 years in the Cardiovascular Health Study. After median follow-up of 9.5 years, 304 (30%) men developed AF. We detected a nonlinear association with risk of incident AF in both free and total DHT, in which subjects with the lowest levels had a higher risk of incident AF.
