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


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).
Our results displayed that the prevalence rate of TD was about 30% in US adult males, and it was higher in males with elder age and higher BMI. These estimates may arouse attention in male health management, especially considering that obesity is quite common among US males [4]. And the occurrence of TD is not only associated with higher age or BMI, but also related to unhealthy dietary habits and environmental pollutant exposure, etc. [5]. Testosterone therapy (TTh) was very popular in treating TD in recent years. However, the clinicians should carefully consider TD diagnosis criteria and individuals' health conditions and maintain necessary laboratory monitoring when carrying out TTh [3]. Our study possessed several limitations. We simply defined TD as a total testosterone level below 300 ng/dL without considering symptoms and/or signs followed with TD [3]. Since only NHANES 2013-2014 and 2015-2016 were available for testosterone data, the number of participants in this study was inevitably small.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Data share statement
Data described in the manuscript, code book, and analytic code will be made publicly and freely available without restriction at www.cdc.gov/nchs/nhanes/.

Ethical approval
The studies involving human participants were reviewed and approved by the NCHS Ethics Review Board.

Informed consent
Informed consent was obtained from all individual participants enrolled in the study.