Temporal trends in testosterone levels and treatment in older men.
Level 5 - mechanism / opinion, no new human data
Narrative review without systematic search or meta-analysis
PubMed 19396984 · doi:10.1097/med.0b013e32832b6348
What was done
The author reviewed literature on temporal (secular) trends in serum testosterone levels in adult and older men, examining disparities between longitudinal and cross-sectional age-decline estimates, potential drivers such as BMI changes and endocrine disruptors, and treatment patterns.
What was found
Existing evidence suggested a secular decline in testosterone concentrations of up to 1% per calendar year in excess of cross-sectional age-related declines. Increases in BMI accounted for part of this trend. Evidence for environmental endocrine disruptors was noted as speculative without longitudinal studies, and data on general population treatment patterns remained limited.
Why it matters
Demonstrating that male testosterone levels may be falling over calendar time independently of chronological aging informs diagnostic thresholds for hypogonadism and highlights potential population-wide metabolic and environmental shifts.
Limits
This is a narrative review lacking a systematic search protocol or quantitative meta-analysis. The abstract provides no specific study count or sample size, and causal drivers of the observed trends remain speculative.
Cited by
- supports Average testosterone levels in men have decreased by up to 20% over the last two decades.