Associations between occupation exposure to Formaldehyde and semen quality, a primary study

Formaldehyde (FA), a ubiquitous environmental pollutant, has long been suspected of having male reproductive toxicity. However, FA male reproductive toxicity was inconclusive due to dearth of human studies. Therefore, we sought to investigate whether occupational exposure to FA affects semen quality. Semen quality including five conventional parameters and seven kinematics parameters were compared between 114 male workers occupationally exposed to FA and 76 referents. FA exposure index (FEI) was measured and calculated. Our results showed that sperm progressive motility, total sperm motility, VCL, VSL and VAP were statistically significant decreased in FA exposure workers compared with the referents. Moreover, FEI was significantly negative associated with sperm progressive motility (β = -0.19, P = 0.01) and total sperm motility (β = -0.23, P = 0.004). In addition, a significant elevated risk of abnormal sperm progressive motility were observed in both low- (OR = 2.58; 95% CI: 1.11-5.97) and high-FA-exposed group (OR = 3.41; 95% CI: 1.45-7.92) respectively. Furthermore, a significant increased risk was also estimated for abnormal total sperm motility in both low- (OR = 3.21; 95% CI: 1.24-8.28) and high-FA-exposed group (OR = 4.84; 95% CI: 1.83-12.81) respectively. In conclusion, our study revealed the adverse effects of FA occupation exposure on semen quality, especially on sperm motion parameters.