CohortHumann = 1,2202026United States
Heat exposure during susceptible windows of spermatogenesis and sperm epigenetic age.
Plain-language summary
Researchers followed 1,220 men at a Utah fertility clinic and matched the outdoor heat and humidity each man lived through while his sperm were forming against a molecular measure of how aged his sperm looked. Men who went through hotter, more humid weather during that window tended to have sperm that looked older at the molecular level. The shift per man was small but showed up consistently across different heat levels.
Key findings
- Hotter, more humid conditions during sperm development were linked to faster epigenetic aging of sperm.
- The link was strongest during a key phase of sperm development.
- Both hotter and colder humid conditions during that phase were tied to faster epigenetic aging.
How to analyze the study yourself
- Study type
- Cohort studies are good at tracking exposures and outcomes over time but can't prove causation due to potential confounding factors.
- Population
- Men from an infertility treatment population in Utah.
- Funding
- Supported by K01ES034005 from the National Institute of Environmental Health Sciences and the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
- Watch for
- Heat and humidity while sperm are forming appear to wear on them. If you are trying to conceive, sustained hot, humid stretches are one more stress worth keeping in mind.