A global decline in birth rates and a rise in infertility have become pressing concerns. In China, for example, the infertility rate has reached 12.5% and continues to rise.
Infertility is defined as the inability to conceive after one year of regular, unprotected sexual intercourse. Studies show that in about 40% of infertile couples, male factors are responsible for the infertility.
Male fertility is influenced by environmental, genetic, and occupational factors. Many men remain in the same living environment and job for years, which means they are exposed to consistent factors that could affect their fertility. Therefore, it is essential to examine how occupation and the environment contribute to male fertility, in addition to genetic predispositions.
Previous studies have suggested that men in the transportation industry tend to have lower sperm motility. Additionally, men working with toxic chemicals, especially in the printing and oil industries, show signs of poor fertility. However, some studies have found no connection between occupation and semen quality, indicating the need for further research.
Living environments also play a role in male fertility. For example, exposure to mobile phone signals has been linked to decreased sperm motility and concentration. Moreover, house renovations involving substances like ammonia, benzene, and formaldehyde may negatively impact semen quality.
In a cohort study, researchers found that environmental noise exposure is associated with sperm abnormalities.
The Study
The recent study aimed to investigate how environmental and occupational factors influence male fertility. Researchers developed three questionnaires focused on demographic details, living conditions, and occupational impacts, based on the lifestyle habits of typical Chinese individuals.
The study recruited couples attending free pre-pregnancy medical exams at the Guangzhou Women and Children’s Medical Center. Males with infertility-related health issues, such as cryptorchidism, azoospermia, or varicocele, were excluded from the study, as well as those who were obese or overweight.
A total of 465 men, aged 31 to 43, participated. Along with completing the questionnaires, participants underwent physical examinations and semen analysis on the same day. All participants were asked to abstain from sexual activity for three to seven days before the analysis. Semen quality was assessed based on factors such as pH, volume, sperm count, concentration, and motility.
Key Findings
The average age of participants was 37.5 years, and the mean body mass index (BMI) was 23.85 kg/m². Around 21% of participants consumed alcohol, and 9% were smokers. All participants were employed full-time.
Men living near power lines and substations exhibited higher sperm counts and better sperm motility, suggesting that electric field energy might have a positive impact on semen quality. However, further research is needed to confirm these results.
In contrast, men living near chemical factories showed poor sperm concentration. This supports earlier studies linking industrial chemicals to deteriorating semen quality.
Fertility is often damaged by a combination of factors over time. Most individuals don’t recognize the impact of these factors until infertility issues arise. It’s important for fertility clinics to consider these environmental and occupational influences when providing treatments.
Conclusion
This study has some limitations. It focused only on Southern China, which means the findings may not apply to other regions or ethnic groups. Moreover, the study only examined general risk factors and didn’t assess specific substances that may contribute to male infertility. Other confounding factors, such as sleep duration, economic status, and diet, were not accounted for in the study.
Despite these limitations, the study underscores the influence of environmental and occupational factors on semen quality. Men working with computers, power lines, transformers, substations, or in chemical factories, as well as those involved in home renovations, are at risk of decreased fertility. Future studies with larger and more diverse sample sizes are needed to confirm these findings.
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