Nationally Representative Estimates of Serum Testosterone Concentration in Never-Smoking, Lean Men Without Aging-Associated Comorbidities

CONTEXT: Testosterone deficiency prevalence increases with age, comorbidities, and obesity. OBJECTIVE: To inform clinical guidelines for testosterone deficiency management and development of targets for nonpharmacologic intervention trials for these men, we determined serum testosterone in never-smoking, lean men without select comorbidities in nationally representative surveys. DESIGN, SETTING, PARTICIPANTS: We used cross-sectional data for never-smoking, lean men ≥20 years without diabetes, myocardial infarction, congestive heart failure, stroke, or cancer, without use of hormone-influencing medications, and participated in morning sessions of National Health and Nutrition Examination Survey (NHANES) III (phase I 1988–1991) or continuous NHANES (1999–2004). By age, we determined median total testosterone (ng/mL) measured previously by a Food and Drug Administration-approved immunoassay and median estimated free testosterone concentration. RESULTS: In NHANES III, in never-smoking, lean men without comorbidities, median (25th, 75th percentile) testosterone was 4% to 9% higher than all men—20 to 39 years: 6.24 (5.16, 7.51), 40 to 59: 5.37 (3.83, 6.49), and ≥60: 4.61 (4.01, 5.18). In continuous NHANES, in never-smoking, lean men without comorbidities, levels were 13% to 24% higher than all men—20 to 39 years: 6.26 (5.32, 7.27), 40 to 59: 5.86 (4.91, 6.55), and ≥60: 4.22 (3.74, 5.73). In never-smoking, lean men without comorbidities, median estimated free testosterone was similar to (NHANES III) or slightly higher than (continuous NHANES) in all men. CONCLUSIONS: These nationally representative data document testosterone levels (immunoassay) in never-smoking, lean men without select comorbidities 30 and 15 to 20 years ago. This information can be incorporated into guidelines for testosterone deficiency management and used to develop targets for nonpharmacologic intervention trials for testosterone deficiency.