Savitz D A
Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill 27599-7400.
Environ Health Perspect. 1993 Dec;101 Suppl 4(Suppl 4):83-91. doi: 10.1289/ehp.93101s483.
Epidemiologic research concerning electric and magnetic fields in relation to cancer has focused on the potential etiologic roles of residential exposure on childhood cancer and occupational exposure on adult leukemia and brain cancer. Future residential studies must concentrate on exposure assessment that is enhanced by developing models of historical exposure, assessment of the relation between magnetic fields and wire codes, and consideration of alternate exposure indices. Study design issues deserving attention include possible biases in random digit dialing control selection, consideration of the temporal course of exposure and disease, and acquisition of the necessary information to assess the potential value of ecologic studies. Highest priorities are comprehensive evaluation of exposure patterns and sources and examination of the sociology and geography of residential wire codes. Future occupational studies should also concentrate on improved exposure assessment with increased attention to nonutility worker populations and development of historical exposure indicators that are superior to job titles alone. Potential carcinogens in the workplace that could act as confounders need to be more carefully examined. The temporal relation between exposure and disease and possible effect modification by other workplace agents should be incorporated into future studies. The most pressing need is for measurement of exposure patterns in a variety of worker populations and performance of traditional epidemiologic evaluations of cancer occurrence. The principal source of bias toward the null is nondifferential misclassification of exposure with improvements expected to enhance any true etiologic association that is present. Biases away from the null might include biased control selection in residential studies and chemical carcinogens acting as confounders in occupational studies.
关于电场和磁场与癌症关系的流行病学研究主要聚焦于居住环境暴露对儿童癌症的潜在病因作用，以及职业暴露对成人白血病和脑癌的潜在病因作用。未来的居住环境研究必须集中于暴露评估，可通过建立历史暴露模型、评估磁场与电线编码之间的关系以及考虑替代暴露指标来加强。值得关注的研究设计问题包括随机数字拨号控制选择中可能存在的偏差、暴露与疾病时间进程的考量以及获取评估生态学研究潜在价值所需的信息。最优先事项是对暴露模式和来源进行全面评估，以及考察居住电线编码的社会学和地理学情况。未来的职业研究也应集中于改进暴露评估，更多关注非公用事业工人人群，并开发优于仅使用职位名称的历史暴露指标。工作场所中可能作为混杂因素的潜在致癌物需要更仔细地研究。暴露与疾病之间的时间关系以及其他工作场所因素可能产生的效应修正应纳入未来研究。最迫切的需求是测量各类工人人群的暴露模式，并对癌症发生情况进行传统的流行病学评估。向无效假设方向的主要偏差来源是暴露的无差异错误分类，预期改进可增强任何存在的真实病因关联。远离无效假设的偏差可能包括居住研究中控制选择有偏差，以及职业研究中化学致癌物作为混杂因素。
