A large-scale study involving over 2,000 men has identified epigenetic alterations in sperm linked to exposure to common air pollutants. The findings, presented at the annual meeting of the European Society of Human Reproduction and Embryology in London, revealed that ozone and nitrogen dioxide are most strongly associated with so-called DNA methylation changes, as reported by the British newspaper The Guardian.
The research was conducted from 2013 to 2017 in Salt Lake City, the capital of the U.S. state of Utah. Participants provided sperm samples upon enrollment, and then again after two, four, and six months. Scientists assessed exposure to pollutants during the three months preceding each sample collection, which corresponds to the sperm production period.
Analysis of samples from 1,220 men after six months uncovered 39 DNA changes linked to pollutant mixtures. One of the genes identified, GNAS, had previously been associated with reduced sperm quality and fetal development. While most epigenetic marks are erased during early embryonic development, some genes may be “imprinted” by these changes, potentially influencing fetal development.
Dr. Carrie Nobles from the University of Massachusetts noted that further research is needed to establish a direct link between DNA methylation changes in sperm and fertility. The scientists emphasized that the current data are not yet sufficient to draw clinical conclusions.
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