As urban populations grow, researchers are investigating the potential impact of living in noisy and polluted environments on fertility.
A recent study from Denmark has explored the relationship between long-term exposure to traffic noise, air pollution, and infertility, revealing that these environmental factors may affect men and women differently.
The study analyzed data on over two million people across Denmark, focusing on those of reproductive age.
Researchers found that long-term exposure to high levels of air pollution and road traffic noise was associated with an increased risk of infertility.
While air pollution, particularly fine particulate matter (PM2.5), was more strongly linked to infertility in men, traffic noise appeared to have a greater impact on women, particularly those over the age of 35.
The study utilized Denmark's extensive national databases to gather information about where people lived and whether they had received an infertility diagnosis. This data linkage method allowed researchers to estimate exposure levels to both air pollution and noise at residential addresses.
The results showed that men exposed to PM2.5 levels significantly above the World Health Organization's recommendations had a 24% higher risk of infertility. For women, a 10.2-decibel increase in traffic noise above average levels (55-60 decibels) was linked to a 14% higher risk of infertility in women over 35.
This study adds to the growing body of evidence that environmental factors like pollution and noise can have both immediate and long-term effects on reproductive health. While men produce new sperm daily, making their fertility more susceptible to rapid changes in environmental exposure, women are born with all their eggs, which are more protected but still vulnerable to long-term damage.
Although the study's reliance on data linkage offers valuable insights, it also has limitations.
The researchers made assumptions about couples' efforts to conceive and their exposure levels based on residential addresses. Future studies that incorporate individual surveys and biological measurements, such as hormone levels, could provide a more accurate understanding of how environmental factors impact fertility.