SUN-136 - Androgen Receptor CAG Length and Testosterone, Body Composition and Performance Variables in the Professional Soccer Players

The purpose of this work was to analyze the relationship between the number of CAG repeats in the androgen receptor (AR) gene and the following variables: total and free testosterone (T), body fat and muscle mass and percentage, and sprint speed after adjustment for age and BMI in professional soccer players (n=23, mean age 24 y, height 183 cm, weight 81 kg). Testosterone was measured via LC-MS. Body composition was assessed through caliper assessment using ISAK-based anthropometric standards. Maximum speed was assessed through the GPS tracking system. Mean body composition, hormonal, and performance data were as follows: body fat 10.89 (±1.47) %, muscle 49.33 (±1.65) %, fat mass 8.8 (±1.5) kg, muscle mass 39.9 (±4.1) kg, total T 489 (±140) ng/dL, free T 12.39 (±2.64) pg/mL, CAG 21.8 (±4.1) repeats, and max sprint speed 33.68 (±1.55) km/h. CAG was not associated with total or free T. CAG correlated negatively with body fat % and fat mass, but this was not statistically significant after adjustment for age and BMI. CAG was not associated with muscle % or max sprint speed. To conclude, in this cohort of professional male soccer players, AR CAG repeat length was not independently associated with total or free T, body composition, or maximal sprint speed after adjustment for age and BMI. Unadjusted correlations suggested that longer CAG repeats tracked with lower adiposity, but these signals attenuated with covariate control, showed no meaningful nonlinearity, and did not operate indirectly via free testosterone in exploratory mediation. Collectively, point estimates were small, and confidence intervals spanned effects that are unlikely to be physiologically important in highly trained men. Interestingly, although normal, free T was on the lower side of the reference range, which is worth further exploration.

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