Abstract: https://www.acpjournals.org/doi/10.7326/M23-0342
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Lower testosterone concentrations are associated with a range of poor health outcomes in aging men, including higher risks for diabetes, dementia, and death. It remains unclear whether reduced testosterone production is intrinsic to male aging or reflects accumulation of age-related comorbid conditions.
Researchers from the University of Western Australia in collaboration with colleagues from Australia, Europe and North America conducted a systematic review and meta-analysis of 11 studies comprising individual participant data from 21,074 men and aggregate data from 4,075 men. The authors analyzed concentrations of testosterone, dihydrotestosterone (DHT), and estradiol which were measured accurately using mass spectrometry. They found that testosterone concentrations did not differ with age until 70 years, after which testosterone concentrations decreased and luteinizing hormone (LH) concentrations increased, suggesting impaired testicular production of testosterone. Testosterone concentrations were slightly lower in men who were married, less physically active, were former smokers, or had hypertension, cardiovascular disease (CVD), or were on lipid-lowering medications. Testosterone concentrations were notably lower in men with higher BMI, or with a history of cancer or diabetes. The authors recommend that interpretation of testosterone measurements in individual men should account particularly for age older than 70 years, higher BMI, and the presence of diabetes or cancer. They conclude that additional research is needed to determine the health implications of reduced testosterone production in men above the age of 70 years.