Air pollution is associated with a higher infertility risk in men, while noise pollution is associated with a higher risk of infertility in women, a study found.
The studypeer-reviewed and published in the BMJ, looked at whether long-term exposure to road traffic noise and fine particulate matter (PM2.5), a particular form of air pollution, was associated with a higher risk of infertility in men and women.
It comes from a database of 526,056 men and 377,850 women aged 30 to 45 who had less than two children, were cohabiting or married, and who lived in Denmark between 2000 and 2017. This subset of the database was chosen to include a high proportion of people who were actively trying to conceive.
The study excluded sterilized men and women who had surgery to prevent pregnancy.
Between 1995 and 2017, the average amount of PM2.5 pollution at the addresses of each participant was recorded, and infertility diagnoses were recorded from the national patient registry.
Over the 18-year period, infertility was diagnosed in 16,172 men and 22,672 women, and after adjusting for factors such as income, education level and occupation, exposure to levels of PM2.5 that were 2.9 micrograms per cubic meter higher was found than averaged over five years was associated with a 24% increased risk of infertility in men aged 30 to 45.
Although PM2.5 was not associated with infertility in women, exposure to levels of road traffic noise that were 10.2 decibels higher than the average over five years was associated with a 14% increased risk of infertility among women over 35, while for women between 30 years of age. and 35 noise was not associated with infertility.
Road traffic noise was associated with a small increased risk of male infertility for those aged 37 to 45, but not those aged 30 to 37.
Infertility affects one in seven couples in the UK trying to conceive.
The researchers said several previous studies had found negative associations between particulate air pollution and sperm quality, but these studies were inconsistent.
They concluded: “Based on a nationwide cohort, designed to include a large proportion of people actively trying to achieve pregnancy, we found that PM2.5 was associated with a higher risk of an infertility diagnosis among men and road traffic noise were associated with a higher risk of an infertility diagnosis among women over 35 years of age, and possibly among men over 37 years of age.
“As many Western countries face declining birth rates and increasing maternal age at the birth of a first child, knowledge about environmental pollutants that affect fertility is crucial. If our results are confirmed in future studies, it suggests that political implementation of air pollution and noise mitigation could be important tools to improve birth rates in the Western world.”
