Long-term exposure to ambient air pollutants and female infertility risk: a population-based cohort study in Taiwan

Infertility affects over 186 million people globally, with about 1 in 7 couples in developed nations experiencing it. Causes include age-related fertility decline and environmental factors. Air pollution is a potential factor, but large-scale evidence is still lacking. This study examines the impact of several air pollutants on infertility in females aged 15 to 60, hypothesizing that air pollution increases infertility risks. We constructed a cohort in Taiwan between July 1, 2003, and December 31, 2013, using the National Health Insurance Research Database (NHIRD) of females aged 15 to 60. Concentrations of SO2, CO, O3, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 were estimated based on insurance registration. We calculated the HRs of exposure at a standard deviation increment for 10 years to determine the dose–response effect between air pollutants and infertility. Long-term exposure to SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 was associated with increased infertility in women of reproductive age. Each standard deviation increase in exposure to these pollutants was associated with a higher incidence of infertility by 13%, 116%, 35%, 77%, 80%, 66%, 76%, 116%, 52%, and 181%, respectively. Conversely, ozone exposure was associated with a 52% reduction in infertility risk. This study demonstrates the significant impact of air pollution on female infertility, showing a clear dose–response relationship between exposure to various pollutants and infertility rates. These findings highlight the need for efforts to reduce air pollution and its effects on reproductive health. Further research is needed to understand the mechanisms and inform public health policies.