- Air pollution appears to alter how sperm genes function, according to one of the largest fertility studies of its kind.
- Men exposed to common air pollutants while sperm were developing showed subtle DNA changes that affected whether genes were switched on or off, raising fresh concerns air pollution may harm male fertility.
- The findings, presented on Tuesday at the annual meeting of the European Society of Human Reproduction and Embryology in London, identified ozone and nitrogen dioxide as the pollutants most strongly linked to these so-called epigenetic changes.
- The study followed more than 2,000 men in Salt Lake City, Utah, between 2013 and 2017.
- Researchers estimated each participant's exposure to outdoor air pollutants during the three months before each sample was collected, corresponding to the period of sperm production.
- Scientists analysed sperm DNA methylation in the 1,220 men who provided a sample at the six-month follow-up, identifying 39 DNA changes linked to air pollution mixtures.
- One of the genes identified, GNAS, has previously been linked to poorer semen quality and foetal development.
- Dr Carrie Nobles, an epidemiologist at the University of Massachusetts Amherst, who led the work, stated that their findings suggest that air pollution exposure during key stages of sperm development may be associated with changes in sperm DNA.
- Prof Allan Pacey, a professor of andrology at the University of Manchester, noted that the study had shown a measurable effect but emphasized that it is not possible to conclude whether the observed changes to sperm DNA methylation are clinically meaningful for male infertility.
- Prof Richard Lea, a professor of reproductive biology at the University of Nottingham, stated that this research adds to a growing body of evidence that sperm quality is adversely affected by airborne pollutants.
- The study's findings raise important questions about whether fathers' environmental exposures may influence not only fertility, but pregnancy and offspring health.
Air pollution exposure during sperm development may lead to significant DNA changes, raising concerns about male fertility and offspring health.111
The study, which included over 2,000 men in Salt Lake City from 2013 to 2017, found that pollutants like ozone and nitrogen dioxide were linked to 39 DNA methylation changes in sperm.34
Dr. Carrie Nobles, the lead author, stated, "Our findings suggest that air pollution exposure during key stages of sperm development may be associated with changes in sperm DNA methylation, including in genes involved in spermatogenesis and early developmental processes."
The research highlights the potential for these changes to affect not just fertility but also pregnancy outcomes and the health of future generations.
Prof. Allan Pacey noted that while the study shows measurable effects, further research is needed to determine the clinical significance of these findings for male infertility.
The study's findings were presented at the 42nd Annual Meeting of the European Society of Human Reproduction and Embryology, emphasizing the urgent need for more research in this area.
Prof. Richard Lea remarked, "This is an important piece of research that adds to a growing body of evidence that sperm quality is adversely affected by airborne pollutants."
The study's abstract will be published in Human Reproduction, a leading journal in reproductive medicine.
“The study, one of the largest of its kind, followed over 2,000 men and found that ozone and nitrogen dioxide were the pollutants most strongly linked to epigenetic changes in sperm DNA. A key gene affected, GNAS, has been previously associated with poorer semen quality and fetal development, raising questions about offspring health.”
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