Bithell J F, Draper G J
Department of Statistics, University of Oxford.
J Epidemiol Community Health. 1995 Aug;49(4):437-9. doi: 10.1136/jech.49.4.437.
A recent study by Knox concludes that cases and "clusters" of two or more cases of childhood leukaemia and non-Hodgkin's lymphoma occur closer to many kinds of industrial installation than to supposedly comparable control locations. It is argued that these findings could be largely or entirely artefactual, the apparent differences arising out of the inappropriateness of the control data. Knox used randomly selected postcode units as controls, a procedure that leads to the comparison of individuals located in areas with typically quite different population densities from those for the cases. The resulting potential for bias is explored and the arguments are exemplified by analysing household data based on postcodes.
诺克斯最近的一项研究得出结论，与所谓的可比对照地点相比，儿童白血病和非霍奇金淋巴瘤两例或更多例的病例及“聚集区”更靠近多种工业设施。有人认为，这些发现可能在很大程度上或完全是人为造成的，明显的差异是由于对照数据不合适所致。诺克斯使用随机选择的邮政编码区域作为对照，这一程序导致将位于人口密度通常与病例所在区域有很大差异的地区的个体进行比较。通过分析基于邮政编码的家庭数据，探讨了由此产生的潜在偏差，并举例说明了相关论点。
