A review and meta-analysis of formaldehyde exposure and pancreatic cancer

Background Most reviews on the carcinogenicity of formaldehyde have focused on cancers of the respiratory tract. Two recent studies have suggested that exposure to formaldehyde may increase the risk for pancreatic cancer. Methods We examine 14 epidemiology studies of workers exposed to formaldehyde where pancreatic cancer rates were reported and use meta-analytic techniques to summarize the findings. We also rank formaldehyde exposures for the industries in these studies. Results We found a small increase of pancreatic cancer risk in the studies overall (meta Relative Risk [mRR] 1.1, 95%CI 1.0-1.3); however, this increased risk was limited to embalmers (mRR 1.3, 95%CI 1.0-1.6) and pathologists and anatomists (mRR 1.3, 95%CI 1.0-1.7). There was no increased risk among industrial workers (mRR 0.9, 95%CI 0.8-1.1) who on average had the highest formaldehyde exposures. Conclusion A small increased risk of pancreatic cancer from formaldehyde exposure cannot be ruled out from the studies examined However; the null findings among industrial workers and the lack of biological plausibility would argue against formaldehyde as a cause. The increased risk of pancreatic cancer among embalmers, pathologists, and anatomists may be due to a diagnostic bias or to occupational exposures other than formaldehyde in these professions. (C) 2001 Wiley-Liss, Inc.