Serum testosterone level and related metabolic factors in men over 70 years old

Background: Sex hormone decline remarkably decreases metabolic function in elderly men. Many degenerative diseases may relate to testosterone deficiency. Objective: To evaluate the serum testosterone concentration in elderly men, its related metabolic and inflammatory factors, and the relationship of metabolic syndrome to testosterone levels. Methods: 381 elderly men (78.8 +/- 4.1 yr old) residing in a veterans' nursing home were enrolled. We measured body height and weight, waist and hip circumferences, body fat, blood pressure, blood glucose and insulin, glycosylated hemoglobin (HbA(1c)), lipid profile, complete blood count, high sensitivity C-reactive protein (hsCRP), total testosterone, and SHBG. Free testosterone was calculated by Nanjee-Wheeler's method. Results: Serum total testosterone levels were 0.20-15.74 ng/ml (free testosterone 11.78-478.31 pmol/l). Total testosterone correlated negatively with body mass index (BMI), waist-hip ratio, body fat, blood glucose, blood insulin, HbA(1c), serum triglyceride, white blood cell (WBC) count and hsCRP; but positively with HDL-cholesterol (HDL-C) and hemoglobin. Multiple regression stepwise forward analysis revealed that BMI values, fasting blood glucose, WBC count, fasting hsCRP and hemoglobin were independent factors related to total testosterone. Furthermore, total testosterone is lower in elderly men with metabolic syndrome, according to National Cholesterol Education Program criteria with a modification of waist circumference. However, free testosterone plays a small role in association with metabolic factors in this elderly men's population. Conclusion: Total testosterone level is significantly related to metabolic and inflammatory factors in elderly men. Low total testosterone may be a significant indicator for development of metabolic syndrome in elderly men.