Life time occupation, smoking, caffeine, saccharine, hair dyes and bladder carcinogenesis

A case-control study of bladder cancer in two northern counties of New Jersey was conducted to investigate a tumour that has been considered to be strongly associated with industrial and environmental exposures. The study population included 75 bladder cancer cases and 142 controls. Cases and controls were matched for race, sex, age, place of birth and place of residence. Statistically significant associations with bladder cancer and risk ratios of greater than 2.0 were found for cigarette smoking and for working in dye, petroleum (fuel) or plastics industries. No statistically significant association was found for: cigar and pipe smoking; caffeine, saccharine and alcohol consumption; and life time occupational history of working in other than dye, petroleum and plastics industries. No statistically significant differences between cases and controls were found in family history of cancer. Risk ratios of at least 2.5 (but without statistical significance possibly because of sample size) were found for workers in rodenticide and printing industries, for cable workers and for cancer in the spouses of bladder cancer cases. Simultaneous multiple primary cancer sites were found in 9.3% of the bladder cancer patients; this is higher than the 0.2-8% reported in the medical literature. The life time occupational history of the bladder cancer cases points to industrial determinants: some are known (petroleum and dye industries) but the association with the plastics industry is new. If our findings are confirmed, investigations will be needed to determine whether any specific chemical or combination of chemicals used in the plastics industry is responsible for bladder cancer induction.