(HealthDay News) — Age-specific cutoff points for low testosterone among men aged 20 to 44 years are substantially higher than the standard cutoff point, according to a study published online in The Journal of Urology.
Alex Zhu, from the University of Michigan in Ann Arbor, and colleagues describe normative total testosterone levels and age-specific cutoffs for low testosterone levels in men aged 20 to 44 years old using data from 1486 US men participating in the 2011 to 2016 National Health and Nutrition Examination Surveys. The authors note that the standard cutoff point for low testosterone is 300 ng/dL. However, that threshold is based on testosterone studies of older men and overlooks the normal age-related decline in testosterone levels.
The researchers found that age-specific middle tertile levels were 409 to 558 ng/dL for 20 to 24 years old, 413 to 575 ng/dL for 25 to 29 years old, 359 to 498 ng/dL for 30 to 34 years old, 352 to 478 ng/dL for 35 to 39 years old, and 350 to 473 ng/dL for 40 to 44 years old. For low testosterone, age-specific cutoff levels were 409, 413, 359, 352, and 350 ng/dL, respectively. Each 1-year increase in age was associated with a 4.3-ng/dL decrease in testosterone level.
“In today’s age of personalized medicine, clinicians can now use age-specific testosterone levels to evaluate young men instead of relying on a ‘one-size-fits-all’ approach,” the authors write.
One author disclosed financial ties to the biopharmaceutical industry.