One in six people worldwide suffers from infertility, a worrying phenomenon that has been increasing significantly. Scientists attribute the causes of weak fertility in both men and women to several environmental factors, citing lifestyles and patterns in urban areas, where more than half of the world’s population lives.
The results of a study conducted in Denmark, and published on the National Library of Medicine (NLM) platform, indicated that long-term exposure to sounds such as car sounds, traffic noise, and polluted air may increase the risk of infertility, depending on the extent to which these causes affect both sexes.
Many people agree that air pollution, especially from car exhaust, has harmful effects on the environment and human health in general. Many studies have proven that there are real links that affect health, including cancer and heart disease. However, the recent study addresses the issue from another perspective, revealing the effect of chemicals that humans inhale from polluted air and how they flow through the blood to the reproductive organs, which may lead to hormonal imbalance or directly damage eggs and sperm.
Although the impact of noise pollution on health is still not sufficiently clear, the study indicated that exposure to sounds, including in areas where there are a large number of cars, may affect stress hormone levels, which in turn affects fertility.
Comprehensive study
The study used comprehensive data across all local areas in Denmark, thanks to the innovative data collection system that captures aspects such as place of residence, occupation, education level and health status. By linking these data within a broad and complex system, it was possible to extract the most important links and complex interactions between health status and the environment.
The study focused on those at risk of receiving a diagnosis of infertility, and identified more than two million men and women of reproductive age. The researchers also identified study participants as being between the ages of 30 and 45, having fewer than two children, and living in the country between 2000 and 2017. People who were diagnosed with infertility before the age of 30 or who lived alone were excluded from the study.
Instead of surveying all participants, the researchers were able to access information about their fertility status from the Danish National Patient Registry. Thanks to their registered addresses and workplaces, they were able to track traffic in the area, focusing on major environmental pollutants such as PM2.5, which are microscopic solid or liquid particles suspended in the Earth’s atmosphere, with a diameter of no more than 2.5 micrometers, and are found in the air as a result of the combustion of chemical compounds, industrial processes, and more.
The study found that 16,172 men and 22,672 women were diagnosed with infertility during the 17-year study period, while it was clear that air pollution was a greater cause of infertility in men by 24%, while women were more likely to suffer from infertility by 14% due to noise and pollution.
The study highlights the clear differences between how men and women’s bodies respond to environmental factors. Men produce sperm continuously after puberty, which means that the effects of toxic pollutants on fertility are quickly apparent. In contrast, women are born with all their eggs, and because they have special mechanisms to protect these eggs from damage, it takes longer for the environmental impact to become apparent in women.