Siemiatycki J, Fritschi L, Nadon L, Gérin M
Epidemiology and Biostatistics Unit, Institut Armand-Frappier, Laval, Quebec, Canada.
Am J Ind Med. 1997 Mar;31(3):280-6. doi: 10.1002/(sici)1097-0274(199703)31:3<280::aid-ajim3>3.0.co;2-1.
The most daunting problem in community-based studies of occupational cancer is retrospective exposure assessment. To avoid the error involved in using job title as the exposure variable or self-report of exposure, our team developed an approach based on expert judgment applied to job descriptions obtained by interviewers. A population-based case-control study of cancer and occupation was carried out in Montreal between 1979 and 1986, and over 4,000 job histories were assessed by our team of experts. The job histories of these subjects were evaluated, by consensus, by a team of chemist/hygienists for evidence of exposure to a list of 294 workplace chemicals. In order to evaluate the reliability of this exposure assessment procedure, four years after the rating was completed, we selected 50 job histories at random and had two members of the expert team carry out the same type of coding, blind to the original ratings for these jobs. For 25 job histories, comprising 94 distinct jobs, the pair worked as a consensus panel; for the other 25, comprising 92 distinct jobs, they worked independently. Statistical comparisons were made between the new ratings and the old. Among those rated by consensus, the marginal distribution of exposure prevalence was almost identical between old and new. The weighted kappa for agreement was 0.80. Among items for which both ratings agreed that there had been exposure, there was good agreement on the frequency, concentration, and route of contact. When the two raters worked independently, the levels of agreement between them and between each of them and the original rating was good (kappas around 0.70), though not as high as when they worked together. It is concluded that high levels of reliability are attainable for retrospective exposure assessment by experts.
在基于社区的职业性癌症研究中，最棘手的问题是回顾性暴露评估。为避免将职位头衔用作暴露变量或自我报告暴露情况时出现的误差，我们的团队开发了一种基于专家判断的方法，该方法应用于访谈者获取的工作描述。1979年至1986年期间，在蒙特利尔开展了一项基于人群的癌症与职业病例对照研究，我们的专家团队评估了4000多个工作经历。一组化学家和卫生学家通过达成共识，对这些受试者的工作经历进行评估，以确定是否有接触294种工作场所化学品清单的证据。为评估这种暴露评估程序的可靠性，在评级完成四年后，我们随机选择了50个工作经历，让专家团队的两名成员进行相同类型的编码，且对这些工作的原始评级不知情。对于包含94个不同工作的25个工作经历，两人组成一个共识小组进行工作；对于包含92个不同工作的另外25个工作经历，他们独立工作。对新评级和旧评级进行了统计比较。在通过共识评级的那些工作经历中，新旧评级的暴露患病率边际分布几乎相同。一致性加权kappa为0.80。在两个评级都认为存在暴露的项目中，在接触频率、浓度和途径方面有很好的一致性。当两名评级者独立工作时，他们之间以及他们各自与原始评级之间的一致性水平良好（kappa约为0.70），尽管不如他们共同工作时高。结论是，专家进行回顾性暴露评估可实现高度可靠性。
