US study finds air pollution exposure may alter sperm DNA in men

A new US study has found that exposure to air pollution may trigger chemical changes in sperm DNA during sperm formation, researchers reported. The study, conducted in Salt Lake City, Utah, between 2013 and 2017, enrolled more than 2,000 men and collected sperm samples at the start of the research and again at two, four and six months. In the final samples from the 1,220 men who completed follow-up, researchers identified 39 DNA methylation changes associated with exposure to air pollutants. Ozone and nitrogen dioxide showed the strongest links to these changes, according to the findings. The researchers also observed alterations in the GNAS gene, which has previously been linked to reduced sperm quality and embryo development. They emphasized that exposure to ozone, nitrogen dioxide, sulfur dioxide and fine particulate matter known as PM2.5 during the roughly three-month sperm formation process may cause epigenetic effects.