Dietary risk factors in human bladder cancer.

Retrospective data on dietary habits, employment history and tobacco use were obtained from 569 bladder cancer patients and 1025 age-matched controls admitted to Roswell Park Memorial Institute. Sex-adjusted relative risks revealed increases in risk for lower levels of an index of vitamin A intake. A similar pattern of risk elevation was associated with infrequent milk and carrot intake. Some elevation of risk was found for heavy coffee drinking but the apparent protective effect for milk consumption was not found to be a spurious result of lower coffee intake. Neither was the role of vitamin A explained by its relationship with smoking or employment in high risk occupations. Some association of bladder cancer with infrequent consumption of cruciferous vegetables was also observed. The findings of this investigation are consistent with tumor inhibition by retinoids in animal studies and the low risk associated with vitamin A in epidemiologic studies of lung cancer.