Bladder cancer among workers in the textile industry: results of a Spanish case-control study

This paper presents results from a case-control study carried out in the county of Mataro, Spain. The study was designed to investigate the possible causes of an unusually high mortality rate from bladder cancer in Mataro county as compared to Spain as a whole, and this report focuses on occupational exposures. The study is based on 57 cases who were hospitalized for or died from bladder cancer between 1978 and 1981. Two controls per case were matched for sex, age, residence, and date of either hospitalization or death. Information was collected on smoking, coffee drinking, and occupation. Occupational histories were then evaluated and coded blind by a group of occupational health physicians. Analyses were carried out by means of conditional logistic regression. Among a group of common occupational sectors, an increased risk for past employment in the textile industry (OR = 2.2; p = .038) was found. Further analyses indicated that the risk is particularly elevated (OR = 4.41; 95% confidence limits; 1.15-16.84) for subjects who worked in dyeing or printing and who were most probably exposed to azo-dyes. Exposure in the textile industry may be responsible for 16% of the bladder cancers in the Mataro area. A list of dyes commonly used in the Mataro textile industries was compiled and cross-checked with lists of substances tested or evaluated for carcinogenesis.