Association of Exposure to Particulate Matter Air Pollution With Semen Quality Among Men in China

Importance

The health effects of exposure to particulate matter (PM) on male fertility remain unclear. Although PM exposure has been linked with semen quality, the results were inconsistent.

Objective

To examine the association of different size fractions of PM (<2.5 μm [PM_2.5], 2.5-10 μm [PM_2.5-10], and ≤10 μm [PM₁₀]) exposure with semen quality in China.

Design, Setting, and Participants

This retrospective cohort study was conducted using data on men whose wives underwent assisted reproductive technology procedures in a tertiary hospital in Shanghai, China, from January 1, 2013, to December 31, 2019. Participants were from 340 prefecture-level cities of China and were followed up from the date of their first visit until December 31, 2019. Data were analyzed from December 1, 2020, to May 15, 2021.

Exposures

Exposure to PM_2.5, PM_2.5-10, and PM₁₀during the entire period (0-90 days before semen ejaculation) and key periods of sperm development (0-9, 10-14, and 70-90 days before semen ejaculation).

Main Outcomes and Measures

Semen quality, including sperm count, concentration, and motility.

Results

A total of 33 876 men were included in the final analysis, with a mean (SD) age of 34.1 (5.7) years and large variation of PM exposure. For example, the median exposure to PM_2.5during the entire period of sperm development was 46.05 (IQR, 34.38-61.65) μg/m³. During the entire period of sperm development, exposures to higher levels of PM were significantly associated with lower total and progressive sperm motility. For total sperm motility, an IQR increase in PM_2.5exposure was associated with an estimated effect decrease of −3.60% (95% CI, −3.93% to −3.26%); an increase in PM_2.5-10exposure, with an estimated effect decrease of −0.45% (95% CI, −0.76% to −0.14%); and an increase in PM₁₀exposure, with an estimated effect decrease of −2.44% (95% CI, −2.91% to −1.96%). Similar results were observed for progressive motility. An IQR increase in PM_2.5or PM₁₀exposures was associated with an estimated effect decrease on sperm progressive motility of −1.87% (95% CI, −2.37% to −1.36%) and −1.05% (95% CI, −1.45% to −0.64%), respectively. However, no significant associations were observed between PM exposure during the entire period of sperm development and sperm count or concentration.

Conclusions and Relevance

These findings suggest that PM exposure may adversely affect sperm motility and highlight the need to reduce ambient particulate air pollution exposure for reproductive-aged men.