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Prolonged exposure to air and noise pollution could increase the risk of infertility, a new study revealed.
Fine particulate matter in the air and road traffic noise contributed to infertility in both sexes, the study found, with air pollution having a greater impact on men and noise pollution more significantly affecting women.
The study, published in the journal BMJon Thursday, explored how exposure to environmental pollutants, common now for people living in cities, impacted reproductive health.
The research, conducted in Denmark, analysed data from 526,056 men and 377,850 women aged 30 to 45 who were cohabiting or married with fewer than two children. The participants were tracked from 2000 to 2017.
PM2.5, tiny particles that can penetrate deep inside lungs and the bloodstream, was linked to a 24 per cent increased risk of infertility in men exposed to higher average levels over five years.
“The results are interesting and seem to confirm the hypothesis that exposure to fine particulate matter air pollution is linked to higher risk of infertility in men,” Dr Allan Pacey, professor of andrology at University of Manchester, who was not involved in the study, said.
“This has been an area of concern for a while but my reading of the literature is that the previous studies have been relatively small and frequently used surrogate markers of infertility such as changes to semen quality. In this current study, the authors have linked exposure to infertility diagnosis, which is more robust in my view.”
PM2.5 exposure did not have a similar effect on women’s fertility.
What did was road traffic noise, which was associated with a 14 per cent higher risk of infertility among women above 35 years of age who experienced elevated noise levels over five years. This association was not observed in women aged 30-35.
“Although noise hasn’t been widely studied in relation to fertility, there’s evidence suggesting a link between noise-induced stress and sleep disturbance, which could impact fertility,” Dr Alison Campbell, chief scientific officer at Care Fertility, who was not associated with the study, said.
For men, road traffic noise showed a slight increase in infertility risk for the 37-45 age group but no significant effect in younger men.
The study’s findings were consistent across regions and socioeconomic groups, suggesting the risks associated with pollution were widespread.
Researchers and other experts, however, cautioned against drawing direct cause-and-effect conclusions. “We should remember this is an association and from the data presented we cannot infer cause or effect,” Dr Pacey said.
“The authors have done a good job in controlling for several important confounders, such as socioeconomic factors but it is possible that the real cause of this association lies with something that it was not possible to measure.”
Although the study controlled for income, education and occupation, it did not account for lifestyle factors like smoking, alcohol use or body mass index, which could influence infertility risk. It also did not measure exposure to pollution and noise outside of the home, such as in the workplace.
Researchers said further studies were needed to confirm the findings and to better understand the potential impact of pollution on fertility.
“If our results are validated, it highlights the importance of implementing policies to mitigate air pollution and noise as part of efforts to enhance reproductive health,” they said.
Air pollution accounted for 8.1 million deaths globally in 2021 by contributing to various health conditions, making it the second leading risk factor for death, according to the UN.
In 2022, despite reductions in emissions, most of the European Union’s urban populations continued to be exposed to damaging levels of air pollutants.
The Independent will be revealing its Climate100 List in September and hosting an event in New York, which can be attended online.
