Flanders W D, Cárdenas V M, Austin H
Division of Epidemiology, Emory University School of Public Health, Atlanta, GA 30329.
Epidemiology. 1993 Jul;4(4):336-41. doi: 10.1097/00001648-199307000-00009.
We use a simple, empirical model to describe the healthy worker effect mortality pattern. Under this simple model, internal comparisons of risk with increasing cumulative exposure will tend to be biased away from the null because of the healthy worker effect. We illustrate the potential magnitude of the bias in a simple situation and show that controlling for time since hire, by means of standard epidemiologic methods, eliminates the bias. Time since hire also is a concern of occupational epidemiologists because of the issue of induction time; sufficient time may not have elapsed among recently hired workers for an exposure to manifest its effect on disease occurrence. Provision for an adequate induction period can be addressed, like the concern raised in this paper, by restricting the analysis to workers first employed many years before the start of the follow-up period.
我们使用一个简单的经验模型来描述健康工人效应死亡率模式。在这个简单模型下，由于健康工人效应，随着累积暴露增加而进行的风险内部比较往往会偏离零假设。我们在一个简单的情形中说明了偏差的潜在大小，并表明通过标准流行病学方法控制自入职以来的时间可以消除偏差。由于诱导期问题，自入职以来的时间也是职业流行病学家所关注的；对于新入职工人来说，可能还没有足够的时间让暴露显现出其对疾病发生的影响。就像本文所提出的问题一样，通过将分析限制在随访期开始多年前首次就业的工人身上，可以解决设置足够诱导期的问题。
