Savitz D A, Kaune W T
School of Public Health, University of North Carolina, Chapel Hill 27599.
Environ Health Perspect. 1993 Apr 22;101(1):76-80. doi: 10.1289/ehp.9310176.
Several studies have found associations between wire configuration codes, a proxy for historical residential magnetic field exposure, and childhood cancer. The Wertheimer-Leeper coding method was modified by eliminating the distinction between thick and thin primaries, distinguishing only between open and spun secondaries, and reducing the number of categories from five to three. The association between the modified code and measured magnetic fields was similar to the association with the original wire code. The modified code was used to reanalyze data from a case-control study of childhood cancer in the Denver metropolitan area. In the original study, cases were diagnosed from 1976 to 1983 among children under age 15 and compared to controls selected through random digit dialing. Wire codes for the residence at diagnosis yielded imprecise elevations of two and above for very high current configuration homes or modest 1.5-fold elevations for a dichotomous wire code. In contrast, the modified Wertheimer-Leeper code generated risk estimates that were both precise and markedly elevated for the high wire code (HWC) compared to low wire code (LWC) classifications, with medium wire code (MWC) showing little or no increase in risk. High wire code yielded odds ratios of 1.9 for total cancers (95% CI: 1.1-3.2), 2.9 for leukemias (95% CI: 1.5-5.5), and 2.5 for brain cancer (95% CI: 1.1-5.5) that were not confounded by measured potential risk factors for childhood cancer. These risk estimates are larger than the dichotomized results and more precise than those from the original five-level wire code, though limitations in the original study remain, particularly potential control selection bias.(ABSTRACT TRUNCATED AT 250 WORDS)
多项研究发现，作为历史居住磁场暴露指标的电线配置代码与儿童癌症之间存在关联。韦特海默 - 利珀编码方法进行了修改，取消了粗、细初级线之间的区分，仅区分开放式和绞合式次级线，并将类别数量从五个减少到三个。修改后的代码与测量磁场之间的关联与原始电线代码的关联相似。修改后的代码被用于重新分析丹佛大都会地区儿童癌症病例对照研究的数据。在原研究中，病例是1976年至1983年期间15岁以下儿童中被诊断出的，与通过随机数字拨号选择的对照组进行比较。诊断时居住地的电线代码显示，对于高电流配置房屋，二级及以上的升高不精确，对于二分电线代码，有适度的1.5倍升高。相比之下，与低电线代码（LWC）分类相比，修改后的韦特海默 - 利珀代码生成的风险估计对于高电线代码（HWC）既精确又显著升高，中等电线代码（MWC）显示风险几乎没有增加或没有增加。高电线代码得出的总癌症比值比为1.9（95%可信区间：1.1 - 3.2），白血病为2.9（95%可信区间：1.5 - 5.5），脑癌为2.5（95%可信区间：1.1 - 5.5），这些不受儿童癌症测量潜在风险因素的混淆。这些风险估计值比二分结果大，比原始五级电线代码的结果更精确，不过原研究中的局限性仍然存在，尤其是潜在的对照选择偏差。（摘要截断于250字）
