Trends in Serum Testosterone Levels Among Adolescent and Young Adult Men
Introduction: Testosterone deficiency has a global prevalence of 10-40% among adult males and nearly 20% among adolescent and young adult (AYA) men.1,2 Furthermore, serum total testosterone (TT) levels appear to be declining at the population level in the past few decades in adult men, but whether the TT levels decline in AYA men remains unclear.
Objectives: To analyze serum testosterone levels in AYA males using nationally representative cross-sectional data from the National Health and Nutrition Examination Surveys (NHANESs) 1999-2016, with the hypothesis that serum TT levels in men have decreased over time.
Methods: NHANES are cross-sectional surveys that examine a nationally representative sample of the US population which oversamples targeted populations, such as Hispanics, non-Hispanic blacks, non-Hispanic Asians, older adults and low-income persons to obtain adequate samples for meaningful subgroup analysis and more reliable variable estimates.
We identified data cycles which had values for serum TT and analyzed changes in serum TT over time while controlling for year of study, age, race, body mass index (BMI), comorbidity status, alcohol use, smoking status and level of physical activity.
During the study periods, three different assays (Biotin-Streptavidin from 1999-2004, IS-Liquid Chromatography from 2011-2012 and High-Performance- Liquid-Chromatography Tandem Mass Spectrometry from 2013 onwards) were used, they have shown comparable testosterone values with only some additional accuracy in the latest assaying modality. We defined AYA as males aged 15-39 as per the National Cancer Institute.
Results: A total of 4,045 men had TT measured from 1999 to 2016. After controlling for confounders, TT was lower among men in the later (2011- 2016) versus earlier (1999-2000) cycles (all p < 0.001).
Mean TT decreased over time: 605.39 ng/dL, 567.44, 424.96, 431.76 and 451.22 for years 1999-2000, 2003-2004, 2011-2012, 2013-2014 and 2015-2016, respectively (p < 0.0001, Figure 1).
Elevated BMI was associated with reduced TT levels (p < 0.0001) with mean BMI increasing from 25.83, 27.21, 27.12, 27.81, 27.96 for years 1999-2000, 2003-2004, 2011-2012, 2013-2014 and 2015-2016, respectively, p ¼ 0.0006.
Interestingly, even in men with a normal BMI (18.5-24.9), TT levels have declined from 664.79 ng/dL to 529.24 ng/dL between 1999-2000 and 2015-2016 (p < 0.05).
Conclusion: This is the first study to report declining testosterone levels in AYA men, which may have large ramifications as low testosterone has been linked to underlying comorbidities and potentially increased mortality risk. Further studies are required to understand the etiology of low testosterone in AYA men.
Patel P, Fantus R, Lakeshwar S, et al. 007 Trends in Serum Testosterone Levels Among Adolescent and Young Adult Men in the United States. The journal of sexual medicine 2020;17:S3-S4. 007 Trends in Serum Testosterone Levels Among Adolescent and Young Adult Men in the United States - ScienceDirect
Introduction: Testosterone deficiency has a global prevalence of 10-40% among adult males and nearly 20% among adolescent and young adult (AYA) men.1,2 Furthermore, serum total testosterone (TT) levels appear to be declining at the population level in the past few decades in adult men, but whether the TT levels decline in AYA men remains unclear.
Objectives: To analyze serum testosterone levels in AYA males using nationally representative cross-sectional data from the National Health and Nutrition Examination Surveys (NHANESs) 1999-2016, with the hypothesis that serum TT levels in men have decreased over time.
Methods: NHANES are cross-sectional surveys that examine a nationally representative sample of the US population which oversamples targeted populations, such as Hispanics, non-Hispanic blacks, non-Hispanic Asians, older adults and low-income persons to obtain adequate samples for meaningful subgroup analysis and more reliable variable estimates.
We identified data cycles which had values for serum TT and analyzed changes in serum TT over time while controlling for year of study, age, race, body mass index (BMI), comorbidity status, alcohol use, smoking status and level of physical activity.
During the study periods, three different assays (Biotin-Streptavidin from 1999-2004, IS-Liquid Chromatography from 2011-2012 and High-Performance- Liquid-Chromatography Tandem Mass Spectrometry from 2013 onwards) were used, they have shown comparable testosterone values with only some additional accuracy in the latest assaying modality. We defined AYA as males aged 15-39 as per the National Cancer Institute.
Results: A total of 4,045 men had TT measured from 1999 to 2016. After controlling for confounders, TT was lower among men in the later (2011- 2016) versus earlier (1999-2000) cycles (all p < 0.001).
Mean TT decreased over time: 605.39 ng/dL, 567.44, 424.96, 431.76 and 451.22 for years 1999-2000, 2003-2004, 2011-2012, 2013-2014 and 2015-2016, respectively (p < 0.0001, Figure 1).
Elevated BMI was associated with reduced TT levels (p < 0.0001) with mean BMI increasing from 25.83, 27.21, 27.12, 27.81, 27.96 for years 1999-2000, 2003-2004, 2011-2012, 2013-2014 and 2015-2016, respectively, p ¼ 0.0006.
Interestingly, even in men with a normal BMI (18.5-24.9), TT levels have declined from 664.79 ng/dL to 529.24 ng/dL between 1999-2000 and 2015-2016 (p < 0.05).
Conclusion: This is the first study to report declining testosterone levels in AYA men, which may have large ramifications as low testosterone has been linked to underlying comorbidities and potentially increased mortality risk. Further studies are required to understand the etiology of low testosterone in AYA men.
Patel P, Fantus R, Lakeshwar S, et al. 007 Trends in Serum Testosterone Levels Among Adolescent and Young Adult Men in the United States. The journal of sexual medicine 2020;17:S3-S4. 007 Trends in Serum Testosterone Levels Among Adolescent and Young Adult Men in the United States - ScienceDirect
