Prevalence of testosterone deficiency among US adult males.

Dear Editor, Testosterone is a fundamental sex hormone made by testicular Leydig cells and affects numerous sexual and nonsexual functions. Testosterone deficiency (TD) is characterized by low testosterone combined with one or more symptoms including decreased muscle mass, libido and energy, poor cognition, and depression [1]. Previous studies indicated that about 7% of men would be affected by TD followed by several sexual and nonsexual symptoms in their 50 s, and the prevalence rate of TD in US males was 12.3% in the 40–69-year-old US male population (estimated from the Massachusetts Male Aging Study) [1,2]. However, the exact prevalent condition of TD in US adult males of all ages is still not clear. Hence, we estimated the prevalence of TD using data from the National Health and Nutrition Examination Survey (NHANES), which represent the condition of the whole non-institutionalized US civilians. We obtained data from NHANES 2013–2014 to 2015–2016, since only these two cycles were available for complete testosterone information. NHANES is an ongoing cross-sectional and multistage probability sample survey to reflect the nutritional and health status of the US population. Participants less than 20 years old or without available testosterone data were excluded from our analysis. And a man with a total testosterone <300 ng/dL can be defined as TD, according to 2018 American Urological Association (AUA) guidelines [3]. The prevalence rate and 95% confidence interval (95% CI) were presented in the overall sample and participants which were stratified by age and body mass index (BMI) condition. The p value for linear trends was calculated from linear regression while treating the NHANES cycle or age and BMI group into continuous variables. Weighted logistic regressions were used to assess the association between age and BMI group and the likelihood of testosterone. All analyses were performed by R version 4.0.5[Q3] and SPSS version 26.0 (IBM, Armonk, NY). A total of 5000 adult males (weighted, N1⁄4 213,316,904) with an average age of 47.51 ± 19.68 (mean ± SD) were included in this study. The overall prevalence rate TD was 26.2 (95% CI, 23.9, 28.6) for NHANES 2013–2014 and 25.8 (95% CI, 22.5, 29.1) for NHANES 2015–2016 (linear p1⁄4 0.8340) (Table 1). And the prevalence rate was significantly higher in elder, overweight, or obese males in both two NHANES cycles. Figure 1 presented the results of multivariable logistic regressions with combined cycles. In general, elder people had a higher risk of TD, especially people aged over 70 years old (OR for age 70–791⁄4 1.95, 95% CI, 1.34, 2.83; OR for age �801⁄4 4.04, 95% CI, 2.80, 5.80). Both