Abstract
We have continued epidemiologic research for potential radiation risks of the public near a nuclear power plant (NPP) in Japan. Superficial increase by ecological studies can raise a social concern even for small radiation risks due to NPP routine operations. Japanese geographical pattern of temporal area variation was examined for digestive cancer mortality in 1972-1997 using Poisson regression. Mortality variation in municipalities was assumed to be determined by a geographical hierarchical structure with six local area blocks, prefectures and areas of medical and health planning. About 64.4% of all solid cancers were digestive cancers of esophagus, stomach, colon, gallbladder, pancreas, liver and others. Relative area variation divided into six local area blocks was large for liver and esophagus cancers although it was small for all digestive cancers combined. The geographical mortality pattern for digestive cancers may confound little the risk assessment of areas near NPPs in contrast with the pattern associated with ATL for leukemia and malignant lymphoma.
