An aromatase polymorphism modulates the relationship between weight and estradiol levels in obese men

Objective: To describe the influence of the TTTA aromatase polymorphism (TTTAn) on the relation between obesity and plasma estradiol (E-2) in obese men. Design: A 2-year cohort study. Setting: Clinical research center. Patient(s): Severely obese men 31 who had had gastric bypass surgery and 118 control(s). Intervention(s): Men were genotyped for the TTTAn CYP19A1 polymorphism. Anthropomorphic measures, plasma E-2, and other hormonal levels were determined at baseline and 2-year follow-up. Main Outcomes Measure(s): Relationships between weight and changes in weight and plasma E-2 were examined in relation to the TTTAn polymorphism. Result(s): The mean age was 46.5 +/- 10.82 years, and mean body mass index was 47.1 +/- 8.46 kg/m(2). The most common repeats were 7 and 11. TTTAn number did not correlate with plasma E-2 in the univariate analysis. When patients were stratified per weight group, the correlation between plasma E-2 and weight was seen only among men with a higher TTTA repeat at baseline and 2 years. Similarly, only men with higher TTTA exhibited reduced E-2 levels after weight loss. Conclusion(s): A higher TTTA repeat is associated with a strengthened relationship between obesity and E-2. The well-established effect of increased weight on plasma E-2 appears to be absent in men with low TTTA numbers. (Fertil Steril (R) 2010;94:1734-8. (C)2010 by American Society for Reproductive Medicine.)