In a recent review published in Antioxidants, researchers described the implications of exposure to air pollutants on male fertility parameters and sexual health.
They further discussed the potential clinical effects of air pollution on male reproductive outcomes and the role of oxidative stress in the method.
Study: Implications of Exposure to Air Pollution on Male Reproduction: The Role of Oxidative Stress. Image Credit: Vladimir Sukhachev/Shutterstock.com
A worldwide decline in male fertility potential, average sperm count, and concentration has been reported in several studies. Lifestyle aspects, environmental exposure, and prenatal conditions are implicated as potential causes of this decline.
The increasing socioeconomic burden of male infertility emphasizes the necessity for thorough investigations into its multifactorial etiology.
Air pollution is a major global health concern affecting almost 2.4 billion people, causing over 6.4 million deaths annually. The classification of air pollutants is complex, involving parameters comparable to phase, source, location, and multiple emission sources, with primary and secondary pollutants originating from each natural and human activities.
Exposure to air pollutants comparable to carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and particulate matter (PM) is understood to contribute to numerous short- and long-term health problems, leading to public health concerns.
While PM exposure is related to cardiovascular and respiratory diseases, NO2, O3, CO, and SO2 have distinct roles in respiratory disorders, cardiovascular issues, and overall well-being, as detailed by previous studies.
Previous studies have explored the impact of air pollution on male fertility. The findings are conflicting, with some indicating negative effects on semen quality, motility, concentration, morphology, and DNA integrity, while others show no association.
As there stays a necessity for a comprehensive understanding of the impact of air pollution on male reproductive health, the current review aimed to collate relevant evidence and moreover make clear clinical considerations.
Effect of air pollution on male reproductive parameters: Evidence from animal and human studies
Various human and animal studies have explored the link between air pollution and basic and advanced male reproductive parameters. Animal studies suggest that exposure to PM2.5 results in reduced sperm count, motility, and increased abnormal morphology in rodents, while inconsistent findings were observed for sperm morphology with PM10 exposure.
Pollutants like SO2 were also related to increased testicular oxidative stress, decreased spermatogonia stem cells, and reduced sperm count. While duration and seasonality of exposure are shown to influence these outcomes, the underlying mechanisms include altered hormonal balance, oxidative stress, and inflammation initiation.
Human studies show that air pollution may reduce semen quality, affecting parameters comparable to volume, sperm concentration, motility, and morphology. Seasonality plays a task, with significant opposed effects observed during spring and autumn.
Although most studies indicate a negative impact of common pollutants on sperm parameters, further research is required to verify these findings.
Moreover, human and animal studies suggest that exposure to those pollutants affects immediate reproductive potential and induces epigenetic changes within the male offspring.
Exposure to environmental pollutants also induces deoxyribonucleic acid (DNA) damage and DNA fragmentation, affecting sperm quality. Pollutants contribute to sperm aneuploidy, with higher prevalence in humans in comparison with other animals, resulting in opposed reproductive outcomes.
Studies show that environmental pollution alters gene expression through epigenetic modifications, disrupting regulatory mechanisms in reproductive cells.
Genetic variations, mutations, and replica number variations result from pollutant exposure, increasing disease susceptibility. Moreover, air pollutants and endocrine disruptors shorten telomere length in sperm cells, reflecting accelerated aging and heightened disease risk.
Effect on male sexual health
Exposure to air pollution is found to be positively correlated with erectile dysfunction in human studies. Animal studies also indicate a possible link between PM2.5 exposure and impotence. Moreover, long-term combined exposure to air pollutants is linked to an increased risk of depression and anxiety, particularly affecting male mental health. Moreover, occupational exposure to Bisphenol A, considered an air pollutant, is related to the next risk of male sexual dysfunction.
Effect on reproductive outcomes
Studies exploring the impact of air pollution on reproductive outcomes present mixed findings. Associations are observed between ambient air pollutants and reduced pregnancy rates in patients undergoing in vitro fertilization (IVF), with disparities across different populations and methodologies.
These disparities could also be potentially explained by retrospective study designs, diverse demographic backgrounds, and individual exposure variations.
Mechanisms of motion
Air pollutants may enter the body through inhalation, dermal uptake, or ingestion, exhibiting diverse molecular mechanisms impacting male fertility. The important thing explored pathways are oxidative stress, inflammation, apoptosis, and blood–testis barrier disruption.
Prolonged exposure to pollutants may produce reactive oxygen species (ROS), causing sperm damage and affecting hormone regulation, resulting in diminished fertility potential.
In conclusion, air pollution may negatively affect a variety of male reproductive parameters, sexual health, and reproductive outcomes through various mechanisms.
The alarming rise in male infertility and the present findings together highlight the necessity for increased awareness and comprehensive research to facilitate regulatory motion towards mitigating the impact of air pollution on male reproductive potential.