Testicular function during adolescence in boys with type 1 diabetes mellitus (T1D): absence of hypogonadism and differences in endocrine profile at the beginning and end of puberty

Abstract

Conflicting results regarding testicular function in adults with type 1 diabetes (T1D) have been reported, but little is known about Leydig and Sertoli cell function during puberty in boys treated with multiple daily insulin doses. Our aim was to assess testicular function in boys with T1D. Pubertal boys with T1D (n = 71) and healthy control boys (Control group; n = 104) who were 10-18 years were studied. Both groups were matched by pubertal stage, age, and BMI. Total testosterone (TT), calculated free testosterone (cfT), SHBG, inhibin B, AMH, and gonadotropin levels were determined. At the beginning of puberty, the T1D group had higher levels of SHBG (p = 0.003) and similar androgen levels than the Control group. At the end of puberty, higher TT, and cfT were observed in T1D compared to the Control group (p < 0.01 and p < 0.001, respectively). Gonadotropins and AMH were similar in both groups. Regression analysis showed that T1D was a significant factor, even after adjusting for Tanner stage and BMI-SDS, affecting TT, cFT, and SHBG levels. BMI-SDS was a significant factor affecting TT and SHBG levels. Higher HbA1c had a negative effect on total testosterone and cFT and a positive effect on SHBG levels in T1D boys. Adolescents with T1D do not exhibit hypogonadism, as shown by normal gonadotropin, testosterone, inhibin B, and AMH levels. However, in T1D boys, HbA1c and BMI-SDS had a negative association with testosterone levels. Elevated testosterone levels are observed during late puberty, which were not present earlier.