Epidemiologic Study of Cancer Mortality among Chloroprene Workers

Both case-control and cohort studies were undertaken from July 1,1969 to June 30,1983 toascertain whether exposure to chloroprene increases the risk of cancer.Fifty-five cases of cancerdeaths were verified,16 of which had histories of exposure to chloroprene ranging from 3 to 23years(median 11 years)with a latent period of 8-27 years,except for one case of 3 years(median12.5 years).Fifty-four pairs were obtained by matching the cancer deaths to noncaneer deathsin accordance with strict requirements.The odds ratio for the paired data was 13,x~2=8.64,P<0.005.The average age at death from cancer of workers exposed to chloroprene was 12.7 yearsyounger than that of unexposed workers,t’=2.98,P<0.001.The total cohort consisted of1213 persons,among whom 149(11.6%)had histories of exposure for over 25 years,381(31.5%)for over 20 years,and 852(70.2%) for over 15 years.The SMR for the total cohort was 2.38(P<0.01),and all SMRs for the high-exposure occupations were of significance(P<0.05orP<0.01),in contrast to those of the low-exposure groups whose SMRs were low or zero.Thus,a dose-response relationship existed.Among the high-exposure occupations,maintenance me-chanics seem to have the highest risk of cancers,and SMRs for liver,lung,and lymphatic cancerswere significant in this group.These results suggested that chloroprene exposure increases therisk of developing cancer.1989 Academic Press,Inc.