Androgen receptor CAG repeat polymorphism is associated with cognitive function in older men

Background Androgen receptors are located throughout the brain, especially in regions involved with learning and memory. Different lengths of a CAG (glutamine) repeat polymorphism in exon 1 of the androgen receptor gene may influence androgen action, with longer repeat lengths conferring decreased androgen sensitivity. Methods We sought to determine if this CAG polymorphism was associated with cognition in older men. Results Among 301 community-dwelling white men (mean age, 73.0 ± 7.1), greater CAG repeat length was associated with lower scores on three cognitive tests (p< .05 for all). In addition, 12 participants (9.8%) had cognitive impairment in the low tertile of CAG repeat length whereas 29 (16.3%) had cognitive impairment in the two higher tertiles (odds RATIO = 1.8; 95% confidence INTERVAL = .9–3.7). Conclusions Research should be directed at identifying the mechanism for this association and to determine if treatment with testosterone prevents cognitive decline.