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The following is a summary of “Does outdoor air pollution cause poor semen quality? A systematic review and meta-analysis,” published in the March 2025 issue of BMC Urology by Margiana et al. 

Air pollutants are suspected to impact semen parameters.  

Researchers conducted a prospective study to examine the association between outdoor air pollution and semen parameters, analyzing observational data to determine its impact on semen quality in adults. 

They systematically searched PubMed, Scopus, and ISI Web of Science using keywords and MeSH terms, including “air pollution” and “semen parameters.” The population, Intervention, Comparison, and Outcome (PICO) framework was applied: P (Adult men), I (Individuals with the highest exposure to air pollutants), C (Individuals with the lowest exposure to air pollutants), O (Semen parameters, including semen volume, total sperm count, sperm concentration, total motility, progressive motility, normal morphology rate, and DNA fragmentation index (DFI)). The overall effect was presented as a weighted mean difference (WMD) and 95% CI analyzed via a fixed (inverse-variance) or random (DerSimonian-Laird) weighted model. Heterogeneity was classified as low (I²< 40%), moderate (I² 40–75%), and high (I² > 75%). 

The results showed that higher exposure to outdoor air pollution was associated with significant decreases in semen volume (WMD: -0.13 mL; 95% CI, -0.21 to -0.05; P = 0.001; I² = 32.1%), sperm concentration (WMD: -12.41 × 10⁶/mL; 95% CI, -23.29 to -1.53; P = 0.03; I² = 98.7%), total motility (WMD: -5.96%; 95% CI, -10.76 to -1.16; P = 0.01; I² = 96.2%), progressive motility (WMD: -4.89%; 95% CI, -9.23 to -0.55; P = 0.03; I² = 98.0%), normal morphology rate (WMD: -2.64%; 95% CI, -4.36 to -0.92; P = 0.003; I² = 94.6%), and significant increases in DNA fragmentation index (WMD: 5.41%; 95% CI, 3.24 to 7.59; P < 0.001; I² = 70.4%). 

Investigators concluded that air pollution impaired sperm parameters. Further prospective cohort studies were needed to clarify the underlying mechanisms. 

Source: bmcurol.biomedcentral.com/articles/10.1186/s12894-025-01728-4