The association of age-related differences in serum total testosterone and sex hormone-binding globulin levels with the prevalence of diabetes

Background: Age-related differences of sex hormones are traditionally considered detrimental to certain diseases particularly in middle-aged and elderly males, however, it is imprudent to conclude without elucidating the influences of other age-related pathophysiology apart from reproductive aging. We sought to examine serum testosterone and sex hormone-binding globulin (SHBG) levels from different decades of life and their associations with the prevalence of diabetes in each respective decade.

Materials and methods: A total of 6296 males participated in this multicenter cross-sectional study, aged between 40-79 years. Information on diabetes and associated risk factors were obtained by questionnaires. Serum total testosterone (TT), SHBG and calculated free testosterone (fT) were determined.

Results: Age-related stable level of TT even with significantly lower level of fT did not result in a higher age-related odds of diabetes. Whereas, age-related higher SHBG level was associated with a lower age-related odds of diabetes [-5.88 % (p = 0.038), -14.28 % (p = 0.003) and -23.53 % (p = 0.001) for males aged 50-59, 60-69, 70-79 years, respectively]. Also, the combined age-related differences of TT and SHBG levels were found associated with a lower age-related odds of diabetes [-2.21 % (p = 0.040), -8.16 % (p = 0.025) and -14.37 % (p = 0.002) for males aged 50-59, 60-69, 70-79 years, respectively].

Conclusions: The differences in hormonal levels of each age group category showed a negative association with the prevalence of diabetes in middle-aged and elderly males, however, this association could be deterred in the presence of obesity.