Minority Predoctoral Fellowship Program

这是一项处理与职业和环境发病率和死亡率研究有关的统计设计和分析问题的建议。总体而言，在人口或社区研究中很难检测到与暴露于环境中发现的特定有毒和危险物质有关的发病率和死亡风险的适度上升。在某些情况下，对职业暴露人群的流行病学研究在量化环境风险方面非常有用，因为工人通常比一般人暴露在更高水平的有毒物质中。这些较高水平的暴露使人们更容易发现和表征与工作场所发现的有毒和危险物质有关的发病率和死亡风险适度上升的情况。然而，职业研究也受到一种被称为健康工作者效应(HWE)的选择偏见的困扰，这种偏见可能扭曲暴露-反应关系的形状，并导致偏向暴露与疾病发病之间没有因果联系的零假设。Tchetgen先生将研究统计方法，这些方法可以用来一致地估计职业暴露的因果发病率或死亡率影响，同时考虑到HWE。除了方法论工作外，Tchetgen先生还将有机会使用这些新方法重新分析在汽车行业职业接触金属加工液的发病率和死亡率研究中收集的数据。虽然一些重点将放在金属加工液案例研究上，但这项研究与环境健康研究最相关，在环境健康研究中，风险评估是最重要的。

This is a proposal to address statistical design and analysis issues related to occupational and environmental morbidity and mortality studies. In general, modest elevations in morbidity and mortality risk associated with exposure to particular toxic and hazardous substances found in the environment will be hard to detect in population or community-based studies. In some cases, epidemiological studies of occupationally exposed cohorts are extremely useful in quantifying environmental risks because workers are generally exposed to higher levels of toxic materials than the general population. These higher levels of exposure make it easier to detect and characterize modest elevations in morbidity and mortality risk associated to toxic and hazardous substances found in the workplace. However, occupational studies are also plagued with a form of selection bias known as the healthy worker effect (HWE) which can distort the shape of the exposure-response relationship and lead to bias towards the null hypothesis of no causal association between exposure and disease onset. Mr. Tchetgen will investigate statistical methods that can be used to consistently estimate the causal morbidity or mortality effect of occupational exposure while accounting for the HWE. In addition to methodologic work, Mr Tchetgen will have the opportunity to use these novel methods to re-analyze data collected in a morbidity and mortality study of occupational exposure to metalworking fluids in the automobile industry. Although some emphasis will be placed on the metalworking fluid case study, this research is most relevant to environmental health studies in general where risk assessment is of prime importance.