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Air quality is linked to a wide range of health issues, including respiratory diseases, cardiovascular complications, and cancer, and the list of concerns continues to grow. Common pollutants may be fundamentally disrupting the genetics of human sperm, and these changes may affect more than just male fertility, according to researchers presenting at the 42nd European Society of Human Reproduction and Embryology (ESHRE) annual meeting this week.
The study, the largest of its kind, was conducted between 2013 and 2017 among more than 2,000 men in Salt Lake City, Utah. Volunteers provided semen samples to researchers initially after enrollment and then at two-, four-, and six-month intervals. The researchers focused specifically on examining changes in DNA methylation in sperm. These chemical shifts control genetic activity without actually rewriting the DNA itself. Methylation changes have already been linked to genes utilized during chromosome organization, cell maintenance, and overall sperm development.
At the same time, the researchers used local data to estimate men’s exposure to outdoor air pollutants during the roughly three months of sperm production, known as spermatogenesis. These included common concerns such as nitrogen dioxide, sulfur dioxide, particulates, and ozone. Although past studies have already found evidence linking air pollution and semen quality, geneticists still don’t fully understand how these harmful outcomes occur at the molecular level.
Researchers pointed to ozone and nitrogen dioxide as some of the most influential pollutants. This pair is often recorded at higher levels in urban areas like Salt Lake City due to natural gas combustion and traffic emissions.
“Our findings suggest that exposure to air pollution during critical stages of sperm development may be associated with changes in DNA methylation in sperm, including genes involved in spermatogenesis and early developmental processes,” study co-author Carrie Nobles, an environmental health scientist at the University of Massachusetts Amherst, said in an accompanying statement.
Researchers identified 39 DNA methylation changes specifically associated with air pollution. GNAS-Imprinted genes associated with poor semen quality and fetal growth. However, the nobleman explained: GNAS The impact is “particularly significant.”
“Imprinted genes can persist throughout early embryonic development, which raises important questions about whether paternal environmental exposures can affect not only fertility but also pregnancy and child health,” she said.
Because these are preliminary findings, Nobles emphasized that it is important for researchers to work now to replicate the results in future studies. She also explained that further research is needed into measurable effects on male fertility and pregnancy, as well as investigating other sources of contamination.
“We know that couples exposed to air pollution often have difficulty conceiving. This may be one of the myriad effects air pollution has on our reproductive health,” Karen Salmon, former ESHRE president, said of the study.
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Andrew Paul is a staff writer at Popular Science.
