Mortality from lymphohematopoietic neoplasms and other causes in a cohort of laminated plastic workers exposed to formaldehyde.

PURPOSE: A possible relationship between exposure to formaldehyde and leukemia-particularly myeloid leukemia-as well as of lymphoid neoplasms has been debated and is still controversial. We thus examined the issue using data from a cohort of workers of a laminated plastic factory sited in Piedmont, northern Italy. METHODS: The study cohort included 2,750 subjects (2,227 men and 523 women) who worked in the factory between 1947 and 2011, for at least 180 days. Follow-up ended in May 2011, for a total of 70,933 person-years of observation. We computed standardized mortality ratios (SMR) and 95 % confidence intervals (CI) using national and (whenever available) Piedmont Region death rates. RESULTS: Overall, there were 417 deaths versus 493.4 expected ones (SMR = 84.5, 95 % CI 76.6-93.0). The SMRs were 79.8 (95 % CI 67.5-93.6) for total cancer mortality, 148.5 (95 % CI 68.0-282.2) for oral cavity and pharynx (three deaths were registered, but not confirmed, as nasopharyngeal cancer), 48.3 (95 % CI 13.1-123.7) for pancreas, 66.1 (95 % CI 13.6-193.0) for larynx, and 96.7 (95 % CI 72.0-127.2) for lung cancer. The SMR of all lymphohematopoietic malignancies was 68.6 (95 % CI 31.4-130.3; nine observed deaths). This tended to increase with duration of exposure and to decrease with period at first exposure, always remaining below 100. There were four deaths from lymphoma (SMR = 74.1, 95 % CI 20.1-189.6) and five deaths from leukemia (SMR = 92.4, 95 % CI 29.9-215.3). CONCLUSIONS: We found no meaningful excess mortality from any lymphohematopoietic nor other neoplasms, except possibly for nasopharyngeal cancer.