Enterline P E
Am Ind Hyg Assoc J. 1985 Mar;46(3):B10-3. doi: 10.1080/15298668591394608.
We have had considerable success in identifying cancer causing agents in the workplace using epidemiologic methods. This success had made us very sensitive to the occurrence of cancer clusters among workers in the belief that identification of some common exposure could reveal the presence of a carcinogen and lead to preventive measures. This intense surveillance is both a blessing and a curse. On the one hand, it is a proven way of discovering environmental causes of cancer. On the other, it leads to false alarms or does not always lead to identification of a causal agent. It is easy to demonstrate, using tables of random number 5, how clusters can occur by chance and to demonstrate that when the number of comparisons made in identifying clusters is known there is a basis for their evaluation. Unfortunately, in most instances, when cancer clusters are detected in the workplace the number of comparisons made is unknown and the statistical significance of the cluster cannot be evaluated. Moreover, it is not usually recognized that in this situation when a study is made as a result of discovering a cluster in a particular population, the cases that make up the cluster cannot be included in a data set which tests the hypothesis that a cluster exists. This paper illustrates the above points by actual experiences.
我们运用流行病学方法在识别工作场所的致癌因素方面取得了相当大的成功。这一成功使我们对工人中癌症聚集现象的出现极为敏感，因为我们相信识别出某种共同暴露可能会揭示致癌物的存在并促成预防措施。这种严密的监测既是幸事也是祸根。一方面，它是发现癌症环境成因的一种行之有效的方法。另一方面，它会导致误报，或者并不总能找出致病因素。利用随机数表很容易证明聚集现象是如何偶然发生的，并且可以证明，当识别聚集现象时所做比较的数量已知时，就有了评估它们的依据。不幸的是，在大多数情况下，当在工作场所检测到癌症聚集现象时，所做比较的数量是未知的，聚集现象的统计学显著性无法评估。此外，人们通常没有认识到，在这种情况下，当因在特定人群中发现聚集现象而进行研究时，构成聚集现象的病例不能被纳入用于检验存在聚集现象这一假设的数据集。本文通过实际案例来说明上述要点。
