Abstract

A historical cohort study of the printing industry was established after an anecdotal report of a cluster of cases of bladder cancer in a newspaper factory in Manchester. The cohort comprised some 9500 men who were members of one or other of two trade unions (the NGA and NATSOPA) in the Manchester area between 1949 and 1963. During the follow up period (1949-83) 3482 deaths occurred among men born in 1890 or later; follow up was 97% complete. The results of the study do not support the hypothesis of an occupational risk of bladder cancer in the printing industry. The NGA have a standardised mortality ratio (SMR) of 63 (95% confidence interval (95% CI) 31-113) and NATSOPA an SMR of 113 (95% CI 67-178) based on 11 and 18 deaths from bladder cancer, respectively. Men involved in newspaper letterpress printing have a high mortality from lung cancer (SMR = 179, 95% CI 144-218) that is consistent with the findings of previous studies. Increased mortality from cancer of the buccal cavity and pharynx was found for NATSOPA workers in the newspaper industry; editorial workers had an SMR of 1053 (95% CI 128-3803) and clerical workers had an SMR of 638 (95% CI 132-1864). This is consistent with a review of published studies, which strongly suggest that workers in the printing industry have an increased risk of mortality from cancers of the buccal cavity and pharynx. Socioeconomic differences in union composition, rather than occupational factors, may account for the lower mortality in the NGA compared with NATSOPA. The NGA, a craft union, had an all causes SMR of 92 (95% CI 88-97), whereas NATSOPA covered a broader span of occupations and skill levels, and had an all causes SMR of 112 (95% CI 106-117); the NATSOPA and NGA all causes rate ratio was 1.21 (95% CI 1.13-1,29).