Bladder-cancer incidence in relation to vegetable and fruit consumption: Aprospective study of atomic-bomb survivors

We examined the relation between consumption of 22 dietary items and subseq uent bladder-cancer incidence in a cohort of atomic-bomb survivors in Japan . Subjects were 38,540 people (14,873 men and 23,667 women) who responded t o a mail survey carried out between 1979 and 1981 and who had no known canc er diagnosed before the start of follow-up (1 January 1980 for men, 1 Febru ary 1981 for women), Consumption frequencies for 22 dietary items were asce rtained with pre-coded answers. As of the end of 1993, there were 114 (83 m en and 31 women) incident cases of bladder cancer among 450,326 person-year s at risk. Statistical analysis was done using Poisson regression for group ed survival data. Consumption of green-yellow vegetables and fruit were pro tectively associated with risk. Adjusted for gender, age, radiation exposur e, smoking status, educational level, body-mass index and calendar time. th e relative risk (RR) for those consuming green-yellow vegetables 2-4 times per week and almost everyday was 0.62 [95% confidence interval (CI) 0.39-0. 98] and 0.54 (95% CI 0.30-0.94) respectively, as compared with those consum ing once per week or less. The corresponding RR for fruit consumption was 0 .50 (0.30-0.81) and 0.62 (0.39-0.99) respectively. Chicken consumption was unexpectedly associated with decreased risk, but additional adjustment for consumption did not change the relation of green-yellow vegetables or of fr uit to risk. The consumption of the other dietary items, including meat and green tea, was not: related to risk. The findings add to evidence that hig h consumption of vegetables and fruit are protective against bladder cancer . Int. J, Cancer 86:132-138, 2000. (C) 2000 Wiley-Liss, Inc.