Formaldehyde exposure negatively impacts semen quality

Men with long-term occupational exposure to formaldehyde tend to have poor semen quality, as reported in a study.

The population-based cohort study included 205 men aged 23–40 years (mean 29.49 years) who had lived in Xi’an, China for 24 months or longer. Researchers measured occupational exposure to formaldehyde using a formaldehyde detector. All participants provided semen sample by masturbation after 3–7 days of abstinence. These samples were assessed using the computer-automated semen analysis system, Baso-Papanicolaou staining, and sperm-chromatin structure assay.

Of the participants, 124 individuals had long-term exposure to formaldehyde, with mean concentrations of 1.49 mg/m³ and mean formaldehyde exposure index (FEI) of 73.72. On the other hand, the 81 men in the control group had low concentration levels (0–0.02 mg/m³).

Analyses revealed that long-term personal occupational exposure to formaldehyde was a significant contributor to poor semen quality. Each one-unit increase in FEI was associated with a change of −0.99 percent (95 percent confidence interval CI, −1.00 to −0.98) in total sperm motility, −0.99 percent (95 percent CI, −0.99 to −0.97) in progressive sperm motility, −0.05 percent (95 percent CI, −0.08 to −0.02) in curvilinear velocity, −0.07 percent (95 percent CI, −0.10 to −0.04) in straight line velocity, −0.07 percent (95 percent CI, −0.10 to −0.04) in time-average velocity, −0.98 percent (95 percent CI, −0.99 to −0.93) in normal sperm morphology, −0.24 percent (95 percent CI, −0.35 to −0.11) in seminal neutral glucosidase, −0.61 percent (95 percent CI, −0.66 to −0.56) in seminal plasma zinc, 0.52 percent (95 percent CI, 0.15–1.02) in beat cross frequency, and 0.10 percent (95 percent CI, 0.06–0.14) in the DNA fragmentation index.

The associations persisted even after adjusting for confounding factors. In subgroup analysis, oxidative stress in semen appeared to increase the effect of formaldehyde exposure on semen quality.