Peer-reviewed article
Mendelian randomization investigation into testosterone's trade-offs between longevity and reproductive fitness.
Zhu Liduzi Jiesisibieke, C Mary Schooling ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This is a genetic epidemiology study investigating the relationship between testosterone levels and two adult outcomes: lifespan and number of offspring. Using a statistical method called Mendelian randomization, the researchers found that higher testosterone in men was associated with slightly more children but a shorter lifespan by about 0.74 years per standard deviation increase. The study does not concern child well-being, health, or development.
Key points
- Higher testosterone in men was associated with 0.03 more children (95% CI: 0.01 to 0.05)
- Higher testosterone in men was associated with 0.74 fewer years of lifespan (95% CI: -1.32 to -0.16)
- Testosterone showed no association with lifespan or fertility in women
- Results were adjusted for body mass index and other confounders
- Higher testosterone was also associated with higher diastolic blood pressure in men
Limitations
This study examines adult outcomes (lifespan and fertility) in the general population and does not assess impacts on children's survival, development, protection or participation. The study uses genetic proxies for testosterone rather than direct measurement, and the magnitude of effects on individual lifespan is small.
Abstract
BACKGROUND: Antagonistic pleiotropy between fertility and survival suggests testosterone may promote fertility at the expense of survival. We investigated sex-specific effects of testosterone on fertility (offspring number) and lifespan (proxied by maternal and paternal attained age), with blood pressure as a control outcome, adjusted for confounders such as body mass index (BMI) using Mendelian randomization. METHODS: We identified independent (r2 < 0.001) genetic variants strongly (p < 5e-8) predicting testosterone in men (bioavailable) and women (total) from the largest genome-wide association studies (GWAS), and applied them to the largest available sex-specific GWAS summary statistics for maternal and paternal attained age, participant fertility, and blood pressure adjusted for sex-specific BMI. RESULTS: Testosterone in men (n = 184,205) was inversely associated with lifespan (-0.74 years per standard deviation increase, 95% confidence interval [CI] -1.32 to -0.16) and was positively associated with fertility (0.03 children, 95% CI: 0.01 to 0.05; n = 209,872) after BMI adjustment. Testosterone was not associated with lifespan or fertility in women. Testosterone was associated with the control outcome in men, i.e. higher diastolic blood pressure after BMI adjustment. CONCLUSIONS: Our findings in men are consistent with antagonistic pleiotropy, i.e. higher testosterone was associated with greater fertility but shorter lifespan.