Statistical Model for evaluating health effects of dioxins around waste incinerators

都市固体废物焚化炉所排放的气体中的二恶荚，可能对生殖健康造成不良影响，这一点一直备受公众关注。最近，日本首次大规模的全国性流行病学研究已经开始研究在日本生活在63个高二恶英排放水平（超过80 ng国际毒性当量TEQ/m^3）的城市生活垃圾焚烧炉10公里范围内的母亲对不良生殖结果的影响。本研究的主要目的是探讨分析上述研究中收集的数据的统计方法，并提出一种适用于更普遍的问题，即假定的点源周围的疾病风险增加的方法。作为检测这种集群的统计方法，Stone的最大似然比检验和得分检验，每个案例的得分到点源的距离的倒数是流行的。在我们的研究中，我们提出了扩展的分数测试的基础上，小面积的数据，（i）它允许我们选择最好的预先指定的参数暴露函数，以避免多个测试问题，（ii）它可以应用于一个可能的情况下，危险物质的水平往往达到峰值，在一定距离的点源。已使用假设数据检查和说明了拟定试验的性质及其把握度，并对上述流行病学研究的研究设计进行了把握度计算。仿真研究表明，所提出的测试的权力高于斯通的测试在所有的替代品考虑。

There has been great public concern that adverse reproductive health effects may be associated with dioxins in emission gases from municipal solid waste (MSW) incinerators. Recently, Japan's first-ever large scale nationwide epidemiological study has begun to examine the association of adverse reproductive outcomes with mothers living within 10km from 63 MSW incinerators with high dioxin emission levels (above 80ng international toxic equivalents TEQ/m^3) in Japan. The primary purpose of our study was to investigate the statistical method to analyze the data collected in the above study and also to propose a method applicable to more general problems of raised disease risk around putative point sources.As statistical method to detect such clusters, Stone's maximum likelihood ratio test and score tests which score each case the reciprocal of the distance from a point source are popular. In our study, we have proposed extensions of score tests based on small area data in that (i)it allows us to select the best among prespecified parametric exposure functions to avoid multiple testing problems and (ii)it can be applied to a possible situation where the hazardous substance levels tend to peak at some distance from a point source. The properties of the proposed tests and their power have been examined and illustrated with hypothetical data and also the power calculation has been conducted on the study design of above-stated epidemiological study. Simulation study shows that the powers of the proposed tests are higher than that of Stone's test over all the alternatives considered.