Abstract
Some results by geographical correlation studies can raise a social concern even for small radiation risks due to nuclear power plant (NPP) routine operations. Our recent analysis showed no increased risk for solid cancer mortality in areas with a NPP in Japan. Further examinations using Poisson regression were conducted for mortality rates from digestive cancers. Digestive cancer constituted about 65.6% of all solid cancers in 100 selected municipalities. A minimum latency of 5 years was assumed from the commissioning year of a NPP. A small decreased risk of digestive cancer mortality in all periods and 20 municipalities with a NPP was found compared with in the remaining 80 control areas. Similar results were seen for each gender but for ages at death of 50 years old or more, especially for stomach cancer. Variations of apparent excess risk were considered to be due to heterogeneities of factors (the environments, life-styles, and disease misclassification) to determine temporal pattern of digestive cancer mortality at old ages as well as statistical randomness. [J Radiat Res 44:431 (2003)]
