Background: The change in the prevalence of hypogonadism with age in men with human
immunodeficiency virus (HIV) infection is subject to debate.
Objective: To address this issue, we diagnosed hypogonadism based on serum levels of free testosterone
(fTST) rather than total testosterone which is thought to be an inaccurate indicator. We also
determined the relationship between age and fTST levels and identified risk factors for hypogonadism
in men with HIV infection.
Methods: We retrospectively reviewed fTST levels and associated clinical factors in 71 wellcontrolled
HIV-infected men who were treated at Teikyo University Hospital between April 2015
and March 2016 and who had data available on serum fTST levels, measured >6 months after starting
antiretroviral therapy. fTST was measured using radioimmunoassay on blood samples collected
in the morning. Risk factors for hypogonadism were identified using Welch’s t-test and multiple regression
Results: The men had a mean (± standard deviation) age of 47.4 ± 13.6 years, and mean (± standard
deviation) serum fTST level of 13.0 ± 6.1 pg/mL. Fifteen (21.1%) men had hypogonadism based on
a fTST <8.5 pg/mL. Serum fTST levels significantly decreased with age (−0.216 pg/mL/year).
Older age and low hemoglobin levels were identified as risk factors for hypogonadism.
Conclusion: The men in the study experienced a more rapid decline in fTST levels with age than
men in the general population (−0.161 pg/mL/year). Serum fTST levels in men with HIV infection
should be monitored, especially in older men and those with low hemoglobin levels.