Mortality from solid tumors among workers in formaldehyde industries: An update of the NCI cohort

Abstract

Background: Formaldehyde, a widely used chemical, is considered a human carcinogen. Methods: We extended follow-up of the largest industrial cohort of workers in formaldehyde industries (n=25,619) by 10 years through 2004. Standardized mortality ratios (SMRs) and rate ratios (RRs) were calculated for deaths from solid tumors using quantitative formaldehyde exposure estimates. Results: During 998,239 person-years, 13,951 deaths occurred. With one additional death, previously observed excesses for nasopharyngeal cancer (n=10) persisted for peak, average intensity and cumulative exposure; RRs in the highest exposure categories were 7.66 (95% CI: 0.94, 62.34), P-trend=0.005, 11.54 (95% CI: 1.38, 96.81), P-trend=0.09, and 2.94 (95% CI: 0.65, 13.28), P-trend=0.06, respectively. For all cancer, solid tumors and lung cancer, SMRs among exposed workers were elevated, but internal analyses revealed no positive associations with formaldehyde exposure. Conclusions: Consistent with previous analyses of this cohort, this update continues to suggest a link between formaldehyde exposure and nasopharyngeal cancer. © 2013 Wiley Periodicals, Inc.