Correlation of Aging and Body Mass Index with the Hypothalamic- Pituitary-Gonadal Axis Hormones in Men, with Diabetes Mellitus

Objective: The objective of this retrospective and cross sectional study was to assess the correlation of aging and body mass index (BMI) with hormones from hypothalamic-pituitary-gonadal (HPG) in patients with and without diabetes mellitus (DM). Research Design and Methods: Electronic medical records of 605 patients were selected using specific exclusion criteria. The subjects were systematically divided into two experimental groups, with and without DM. Results: There was a significant negative correlation between age and serum free testosterone and significant positive correlations between age and serum LH and FSH in both groups. BMI was significantly higher in diabetics. In diabetics, BMI was negatively correlated with free testosterone, but no relationship with LH or FSH existed. In contrast, in nondiabetics, BMI was negatively correlated with LH and FSH only. In diabetics, a significant reverse correlation between HbA1c and free testosterone was present and they also had significantly lower FSH. Inappropriately normal LH with low free testosterone levels were seen in majority of patients from both groups. But more diabetics had inappropriately normal FSH with low free testosterone, 88% of diabetics and 70% of control group p<0.01. Conclusion: The data from this cross sectional study showed aged men, in both cohorts, had lower free testosterone and higher LH and FSH. Patients with good blood sugar control had higher serum free testosterone. In addition, FSH was significantly lower and impaired FSH response to low free testosterone was more pronounced in subjects with diabetes.