High dose testosterone therapy for reduction of final height in constitutionally tall boys: does it influence testicular function in adulthood?

Objective: We have studied the effect of treatment with high doses of androgens during puberty on testicular function in adult men with constitutionally tall stature, taking into account confounding factors interfering with sperm quality, since existing published data do not include whether testicular function is impaired by such treatment.

Design: Historical cohort study.

Patients: Forty-three previously androgen treated tall men (cases) and 30 non-treated tall men (controls).

Measurements: Physical examination, semen analysis and plasma levels of LH, FSH, testosterone (T), sex hormone binding globulin (SHBG) and inhibin.

Results: Sperm quality and testis volume were comparable between cases and controls. Mean sperm concentration was 66.4 x 10(6)/ml in cases and 66.2 x 10(6)/ml in controls. A left-sided varicocele was found in 45% of the cases and 37% of the controls. In cases we observed a significant effect of the age at start of androgen therapy on sperm motility (regr. coeff. (SE): 4.92 (2.41)%, P = 0.048). In addition, testicular size at start of therapy had a significant effect on sperm concentration (regr. coeff. (SE): 5.57 (1.54) x 10(6)/ml, P = 0.0012) and on total sperm count (regr. coeff. (SE): 43.1 (7.73) x 10(6), P = 0.0001). Plasma levels of T, SHBG and inhibin were not statistically different between the groups. Cases had significantly higher FSH levels (mean (SD) 3.3 (2.2) vs 2.1 (0.8) IU/I, P = 0.004) and significantly lower LH levels (mean (SD) 2.3 (0.9) vs 3.1 (1.4) IU/I, P = 0.019). We found a significant effect of age at start of therapy on plasma FSH level in the treated men (regr. coeff. (SE): -0.73 (0.18) IU/I, P = 0.0003).

Conclusions: Treatment with high doses of androgens for reduction of final height in constitutionally tall stature has no long-term side-effect on sperm quality, testicular volume or plasma testosterone levels. However, treated men had significantly higher plasma levels of FSH compared with controls. The meaning of this difference remains to be established. Varicocele was present in 42% of the adult tall men.