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

Key Points

Question

Is exposure to different fractions of particulate matter (<2.5, 2.5-10, and ≤10 μm in diameter) associated with poor semen quality?

Findings

In this cohort study of 33 876 Chinese men, decreased total and progressive sperm motility and increased risk of asthenozoospermia were associated with exposure to particulate matter of less than 2.5 μm and 10.0 μm or less.

Meaning

These findings suggest that control measures to reduce exposure to ambient particulate matter may help increase male fertility and reduce the risk of asthenozoospermia.

Abstract

This cohort study evaluates the association between exposure to different particulate matter fractions and poor semen quality among Chinese men whose wives underwent assisted reproductive technology procedures.

Abstract

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 [PM ₁₀]) 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 PM ₁₀ during 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 _2.5 during the entire period of sperm development was 46.05 (IQR, 34.38-61.65) μg/m ³. 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 _2.5 exposure was associated with an estimated effect decrease of −3.60% (95% CI, −3.93% to −3.26%); an increase in PM _2.5-10 exposure, with an estimated effect decrease of −0.45% (95% CI, −0.76% to −0.14%); and an increase in PM ₁₀ exposure, 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 _2.5 or PM ₁₀ exposures 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.