Rosenberg MA, et al. - Researchers hypothesized that low serum androgens are correlated with a higher risk of atrial fibrillation (AF). They tested this hypothesis in otherwise healthy men with an average age 76.3 ± 4.9 years in the Cardiovascular Health Study. They assessed the prospective links between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex hormone–binding globulin (SHBG) with risk of AF among study participants. They found an increased risk of incident AF related to low free DHT among older men, compared with men with higher levels, after adjusting for demographics, clinical risk factors, left atrial diameter, and serum NT-proBNP levels.