Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China.
Level 4 - case-series / case-control
Cross-sectional observational study
PubMed 39342804 · doi:10.1016/j.ebiom.2024.105369
What was done
In a cross-sectional study across three regions in China, semen and urine samples from 113 men were analyzed using Raman microscopy to detect eight types of microplastics (PS, PP, PC, PE, PVC, PTFE, PET, ABS). Semen quality parameters—total sperm count, concentration, progressive motility, and morphology—were evaluated against microplastic exposure profiles using multivariable regression and latent category analysis, adjusting for age, BMI, smoking, alcohol use, and study site.
What was found
Microplastics were detected in 100% of semen and urine samples, with participants typically exposed to 3 to 5 types (PS, PP, and PE had the highest detection rates). Each additional type of microplastic detected was associated with a significant decrease in total sperm count (β = -15.4 million, 95% CI: -25.6 to -5.2), sperm concentration (β = -7.2 million/mL, 95% CI: -12.4 to -2.0), and progressive motility (β = -8.3%, 95% CI: -13.5 to -3.1). PTFE exposure was specifically associated with lower sperm concentration (52.13 ± 47.47 vs. 58.32 ± 37.26 million/mL, p = 0.041), and latent category exposure grouping was associated with increased odds of decreased semen quality (OR = 3.5, 95% CI: 1.8 to 6.9, p < 0.001).
Why it matters
This study provides direct human biomonitoring evidence that mixed microplastic exposure reaches the male reproductive tract and correlates with measurable declines in semen parameters.
Limits
The cross-sectional design precludes causal inference, and the sample size is relatively small (n = 113) from a single country. Semen and urine were measured at a single time point, which may not capture longitudinal exposure variability, and unmeasured environmental co-exposures could not be fully ruled out.
Cited by
- supports Higher levels of plastics like PVC in the reproductive system are linked to lower sperm counts.
- context Microplastics in semen, particularly PVC particles, were linked to abnormal sperm shape and impaired motility.