Social life factors affecting major malignant neoplasms in Japan.

The effects of a wide variety of social life factors on the mortality of five major malignant neoplasms, i.e. those of the stomach, lung (and trachea and bronchus), breast and uterus, and leukemias, in 46 prefectures in Japan were analyzed by stepwise regression analysis twice at a 5-year interval. The results indicated the following three predisposing factors for malignant neoplasms: rural residence for leukemias; urban residence for the remaining four neoplasms including those of the uterus and stomach; and low income for the neoplasms of the uterus and lung (and trachea and bronchus). On the other hand, old age was assumed to be the protective factor for the mortality of the neoplasms of the breast. It is suggested that urban residence is the principal factor affecting the mortality of various malignant neoplasms in Japan.