Formaldehyde exposure may reduce men’s fertility
MedWire News: Occupational exposure to formaldehyde may reduce a man's fertility, say researchers.
Formaldehyde is used worldwide in many processes including construction, wood processing, and furniture manufacture, as well as in hospitals, laboratories, and the chemical industry.
Production of the chemical in China has increased exponentially over the past few years with a corresponding increase in occupational exposure to formaldehyde at levels above the suggested limit of 0.50 mg/m3, primarily through inhalation. Indeed, some extreme instances have recorded exposure levels ranging from 5.84 to 20.94 mg/m3.
As formaldehyde exposure has been shown to inhibit spermatogenesis in rodents, Dang-Xia Zhou (Xi'an Jiatong University, China) and colleagues investigated whether occupational exposure to the chemical could have a similar effect in men.
The team compared reproductive details collected via questionnaire from 302 men exposed to formaldehyde at work and 305 control men with no exposure to the chemical.
Following adjustment for confounders, Zhou and co-authors found that the wives of the men who had been exposed to high amounts (above the median) of formaldehyde were a significant 2.83-fold more likely to have a prolonged time to pregnancy (defined as 12 months or more of unprotected sex before pregnancy) than the wives of men in the control group. They were also a significant 1.92 times more likely to undergo spontaneous miscarriage than the wives of men in the control group.
However, no links between formaldehyde exposure and preterm birth, low birthweight, skewed gender ratios, and birth defects were observed.
When the men in the formaldehyde-exposed group were divided at the median exposure level into "low" and "high" groups in terms of exposure, there was a significant skew in the gender ratio of babies born to the men's wives with 1.71-fold more girls being born to the high- versus the low-exposure group men.
The investigators suggest that this "might be due to the probability of misclassification bias or an endocrine disruptor effect of formaldehyde."
Writing in the Journal of Occupational and Environmental Medicine, they conclude: "In view of the importance of human reproductive health and the current widespread usage of formaldehyde in China, it is important to investigate further the correlation between formaldehyde exposure and semen quality in a large cohort."
By Helen Albert