Serum insulin-like growth factor-I and serum testosterone status of elderly men in an inpatient rehabilitation unit

This study was designed to estimate the prevalence of hyposomatomedinemia and hypogonadism in an inpatient rehabilitation unit. The authors studied healthy young men (HOM) ages 20-29 years (n=33); healthy old men (HOM) ages 59-98 years (n=27), and elderly men in an inpatient rehabilitation unit (ERM) ages 58-95 years (n=42). Serum concentrations of insulin-like growth factor (IGF-I), total testosterone (TT), and free testosterone (FT) were measured. A low IGF-I level (below the lower 2.5 percentile of HYM) occurred in 85% of the HOM and in 62.5% of the ERM. When a low IGF-I was defined as a value below the 2.5 percentile of the HOM, the prevalence in ERM was 6.2%. A low TT level (below the lower 2.5 percentile of the HOM) occurred in 78% of the HOM and in 90% of the ERM. Low TT, defined as a value below the lower 2.5 percentile of the HOM, occurred in 22% of the ERM. The results with FT were similar. In neither HOM nor ERM was IGF-I significantly correlated to TT and FT. A large percentage of HOM and ERM have severe hypogonadism (TT