Increased Estrogen Rather Than Decreased Androgen Action Is Associated with Longer Androgen Receptor CAG Repeats.

Context: The individual variability in the waning androgenic-anabolic functions of aging men may be influenced by the CAG repeat polymorphism in exon 1 of the androgen receptor (AR), affecting androgen sensitivity. However, findings on its phenotypic effects are inconclusive. Objective: The aim was to investigate the relationships between health status, various reproductive hormones, and the AR CAG repeat length. Design: We conducted a multinational prospective cohort observational study with cross-sectional baseline data. Setting: This was a population survey of community-dwelling men. Participants: Men (40–79 yr old; n = 3369) were randomly recruited from centers in eight European countries; CAG repeat analysis was performed in 2878 men. Main Outcome Measures: We measured the correlations of the CAG repeat length with selected endocrine, metabolic, and phenotypic parameters related to aging and sex hormone action. Results: Only minor differences were found in CAG repeat lengths between the eight Europea...