Finkelstein M M
Health and Safety Studies Unit, Ontario Ministry of Labour, Toronto, Canada.
Am J Ind Med. 1995 Jul;28(1):41-7. doi: 10.1002/ajim.4700280104.
Cumulative exposure is frequently used as a measure of exposure in the quantitative analysis of epidemiologic studies. It is recognized that the imposed symmetry between duration and intensity of exposure is a potential problem with this measure, but it is less widely recognized that the finding of an exposure-response relationship, using cumulative exposure as the exposure metric, does not necessarily imply that exposures were accurately or even consistently estimated. This report describes a simulation study drawn from a nested case-control analysis of mesothelioma in a cohort of asbestos cement workers. Intensity of exposure in the range of 0.1-40 fibers/ml was randomly assigned to subjects. Logistic regression analysis demonstrated that there was no association between mesothelioma risk and the randomly assigned intensity of exposure. However, in 171 (86%) of 200 trials, mesothelioma risk was significantly associated with cumulative exposure, even though intensity of exposure remained randomly assigned. A strong exposure-response relationship might thus be misleading. One would be more confident about quantitative risk assessment when there are a large number of independent studies available for analysis.
在流行病学研究的定量分析中，累积暴露常常被用作暴露的一种度量。人们认识到，在这种度量方式下，暴露持续时间和强度之间的强制对称性是一个潜在问题，但较少有人广泛认识到，以累积暴露作为暴露指标发现暴露-反应关系，并不一定意味着暴露得到了准确甚至一致的估计。本报告描述了一项模拟研究，该研究源自对一组石棉水泥工人间皮瘤的巢式病例对照分析。将0.1 - 40纤维/毫升范围内的暴露强度随机分配给受试者。逻辑回归分析表明，间皮瘤风险与随机分配的暴露强度之间没有关联。然而，在200次试验中的171次（86%）中，即使暴露强度仍为随机分配，间皮瘤风险与累积暴露显著相关。因此，强烈的暴露-反应关系可能会产生误导。当有大量独立研究可供分析时，人们对定量风险评估会更有信心。
