A COHORT STUDY OF WORKERS EXPOSED TO FORMALDEHYDE IN THE BRITISH CHEMICAL-INDUSTRY - AN UPDATE

A cohort study of workers exposed to formaldehyde in the British chemi cal industry in any one of six factories has been extended after the e arlier published report in 1984. A further eight years of follow up to the end of 1989 have been included for the originally reported 7660 w orkers first employed before 1965, and a first follow up to the same d ate has been carried out for 6357 workers first employed since 1964. E xtensive checking of the database has taken place including records at the factories, the MRC Environmental Epidemiology Unit, and the Natio nal Health Service Central Register. The updated findings include one death from nasal cancer compared with 1-7 expected in this number of m en during the follow up period-which gives no support to the original hypothesis based on animal experimental data that formaldehyde may be a nasal carcinogen in humans. There have been no cases of nasopharynge al cancer in the cohort compared with an estimated 1.3 expected-which gives no support to the findings in a similarly designed study in the United States of an excess of cancers of the nasopharynx associated wi th exposure to formaldehyde. There has been a slight excess of about 1 2% for lung cancer with 402 deaths compared with about 359 expected. T his is similar to that found in the United States study, but higher th an we reported earlier before the checking procedures and extended fol low up. Further analysis gives no definitive indication of this excess of lung cancer being clearly related to formaldehyde exposure, and th e increase is within that generally thought consistent with possible c onfounding effects of cigarette smoking (although no data are availabl e on this point).