Occupational exposure to formaldehyde in Chinese men may be linked to reduced fertility, reports a paper in the May Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM).

Dr Dang-xia Zhou of Xi'an Jiaotong University in Xi'an, China, looked for evidence of fertility problems among approximately 300 married men exposed to formaldehyde at a wood processing facility in China. Key reproductive outcomes were compared for the wives of men with and without occupational formaldehyde exposure.

The wives of formaldehyde-exposed men had longer times to pregnancy (TTP) than the wives of men not exposed to formaldehyde. With adjustment for other factors, the rate of prolonged TTP was nearly three times higher for wives of men exposed to formaldehyde.

Formaldehyde exposure was also associated with a higher rate of miscarriage (spontaneous abortion). After adjustment, the risk for miscarriage was nearly twice as high in women whose husbands were exposed to formaldehyde at work.

The reproductive toxicity appeared "dose dependent," with higher rates of fertility problems for wives of men exposed to higher levels of formaldehyde. Other reproductive outcomes -- such as preterm birth or birth defects -- were unrelated to formaldehyde exposure.

Formaldehyde is an important chemical used in many different industries. In recent years, China has surpassed the United States as the world's largest producer and consumer of formaldehyde. Most previous studies of formaldehyde's possible reproductive toxicity have focused on women, with inconsistent results.

Together with recent animal studies, the new results suggest that formaldehyde could be a contributor to well-documented reductions in sperm quality worldwide. However, the researchers emphasize that further studies -- including data on the direct correlation between formaldehyde exposure and sperm quality -- would be needed to address this issue.