Exposure to Fine Particulate Matter Constituents and Human Semen Quality Decline: A Multicenter Study

Abstract

Exposure to fine particulate matter (PM < 2.5 μm in diameter [PM 2.5 ]) may accelerate human sperm quality decline, although research on this association is limited. Our objective was to investigate the relationship between exposure to the chemical constituents of PM 2.5 air pollution and decreased sperm quality and to further explore the exposure−response relationship. We conducted a multicenter population-based cohort study including 78,952 semen samples from 33,234 donors at 6 provincial human sperm banks (covering central, northern, southern, eastern, and southwestern parts of China) between 2014 and 2020. Daily exposure to PM 2.5 chemical composition was estimated using a deep learning model integrating a density ground-based measure network at a 1 km resolution. Linear mixed models with subject-and center-specific intercepts were used to quantify the harmful impacts of PM 2.5 constituents on semen quality and explore their exposure−response relationships. Per interquartile range (IQR) increase in PM 2.5 exposure levels during spermatogenesis was significantly associated with decreased sperm concentration, progressive motility, and total motility. For PM 2.5 constituents, per IQR increment in Cl − (β: −0.02, 95% CI: [−0.03, −0.00]) and NO 3 − (β: −0.05, 95% CI: [−0.08, −0.02]) exposure was negatively associated with sperm count, while NH 4 + (β: −0.03, 95% CI: [−0.06, −0.00]) was significantly linked to decreased progressive motility. These results suggest that exposure to PM 2.5 chemical constituents may adversely affect human sperm quality, highlighting the urgent need to reduce PM 2.5 exposure.

Ambient Ozone Exposure, Semen Plasma Metabolites, and Sperm Quality Decline among Adult Men in Wuhan China

“…To explore the nonlinear relationship, we modeled restricted cubic spline function for O 3 concentration in the regression analysis while controlling for the same set of covariates as in the main models. 6,29 We tested the nonlinearity through visual examination and likelihood ratio tests that compares models incorporating nonlinear terms against those using linear terms. 30 To select candidate metabolites, a univariate linear regression model was modeled between O 3 levels and semen quality.…”

“…We employed a multivariate linear regression model to assess the associations of O 3 exposure with semen quality. The model was adjusted for a range of variables identified from previous research, , such as age (under 33 vs 33 and older), body mass index (BMI) (below 24.0, between 24.0 and 28.0, above 28.0 kg/m 2 ), ever having fathered a child (no vs yes), educational level (below college vs college and above), smoking status (no vs yes), monthly income (below 5000, 5001–10 000, over 10 001 CNY), and daily ambient air temperature with 3 degrees of freedom using a natural cubic spline fitting, along with the number of days of abstinence (less than 4 vs 4 or more days).…”

“…It has been estimated that approximately 15%–20% of couples globally, nearly 48.5 million, are affected by infertility attributed to inferior semen quality . Environmental determinants can lead to abnormalities in semen quality, such as nonoptimal ambient temperature, , exposure to heavy metals/metalloids, and ambient air pollution. − …”