Work-related bladder cancer risks in male Japanese workers: estimation of attributable fraction and geographical correlation analysis.

One hundred and forty-nine relative risks (RRs) on occupations and bladder cancer were extracted from 27 case-control studies and geometric means were calculated for 27 occupations as summary RRs. Those in high risk occupations, among whom the summary RRs significantly exceeded unity, were found to be petroleum workers (RR = 3.51), dye workers (RR = 3.38), machinists (RR = 2.76), drivers (RR = 2.22), rubber workers (RR = 2.19), printers (RR = 2.12), clothing/tailors (RR = 2.10), wood workers/carpenters (RR = 1.70), miners (RR = 1.68), textile workers (RR = 1.63), mechanics (RR = 1.54), engineers (RR = 1.54), leather workers (RR = 1.49), painters (RR = 1.48) and chemical workers (RR = 1.44). The estimated numbers of male bladder cancers in 1980 in the high risk and other occupations were 820 and 2065 cases, respectively. The estimated number of work-related bladder cancer was 548 cases, the attributable fraction being 19% in active employees and 12% in the entire population. The geographical distribution of male bladder cancer deaths in Japan was positively correlated with the distributions of workers in the transport/communications industry and in tertiary industries including services, wholesale, retail, finance and insurance, whereas it was negatively correlated with the distribution of workers in the agricultural industry. These findings suggest that workers in certain industries may be at high risk of bladder cancer, but lifestyle modification associated with urbanization and industrialization could be an alternative explanation.