Temporal and Spatial Excess Leukemia Deaths Around the Nuclear Power Plant in Kyushu, Japan (1970-2005)

Abstract

Background/AimExcess incidence of cancer including leukemia among people living in the vicinity of Nuclear Power Plant (NPP) in normal operation has been reported on from Germany, France, the United Kingdom, Korea, and others. But in Japan, any epidemiologic investigations have not been conducted yet while 18 NPP facilities have discharged radioactive substances e.g. tritium. 13 among 47 prefectures in Japan had NPPs until 2010, and 7 of them were ranked in top 15 leukemia mortality. We estimated the Standardized Mortality Ratios (SMRs) on leukemia of municipalities around the NPPs in Kyushu area, the western parts of Japan, and then summarized their temporal-spatial changes with using empirical Bayesian estimates.MethodsWe estimated leukemia SMRs with using data of age-sex specific five-year municipal population among 1965-2005 of Japanese Census, age-sex specific cause-specific leukemia deaths of Japanese Vital Statistics, and leukemia deaths of each municipalities. To adjust spatial variations of SMRs in the towns and villages with sparse population, we have applied empirical Bayes method with Poisson distribution model.ResultsSMRs of leukemia in the study region increased after beginnings of the operation of NPPs. The municipalities located the nearest to NPP had excess SMR (3.69: 95% CI, 3.11-5.56) comparing to farther areas of the prefecture. NPP Reactor type of the study areas was Pressurized Water Reactor (PWR) which released more radioactive substances comparing to Boiling Water Reactor (BWR). The study suggests the relationship between leukemia and NPPs normally operated in Japan.