Bowman J D, Thomas D C, London S J, Peters J M
Department of Preventive Medicine, University of Southern California, Los Angeles, USA.
Bioelectromagnetics. 1995;16(1):48-59. doi: 10.1002/bem.2250160111.
We present a hypothesis that the risk of childhood leukemia is related to exposure to specific combinations of static and extremely-low-frequency (ELF) magnetic fields. Laboratory data from calcium efflux and diatom mobility experiments were used with the gyromagnetic equation to predict combinations of 60 Hz and static magnetic fields hypothesized to enhance leukemia risk. The laboratory data predicted 19 bands of the static field magnitude with a bandwidth of 9.1 microT that, together with 60 Hz magnetic fields, are expected to have biological activity. We then assessed the association between this exposure metric and childhood leukemia using data from a case-control study in Los Angeles County. ELF and static magnetic fields were measured in the bedrooms of 124 cases determined from a tumor registry and 99 controls drawn from friends and random digit dialing. Among these subjects, 26 cases and 20 controls were exposed to static magnetic fields lying in the predicted bands of biological activity centered at 38.0 microT and 50.6 microT. Although no association was found for childhood leukemia in relation to measured ELF or static magnetic fields alone, an increasing trend of leukemia risk with measured ELF fields was found for subjects within these static field bands (P for trend = 0.041). The odds ratio (OR) was 3.3 [95% confidence interval (CI) = 0.4-30.5] for subjects exposed to static fields within the derived bands and to ELF magnetic field above 0.30 microT (compared to subjects exposed to static fields outside the bands and ELF magnetic fields below 0.07 microT). When the 60 Hz magnetic fields were assessed according to the Wertheimer-Leeper code for wiring configurations, leukemia risks were again greater with the hypothesized exposure conditions (OR = 9.2 for very high current configurations within the static field bands; 95% CI = 1.3-64.6). Although the risk estimates are based on limited magnetic field measurements for a small number of subjects, these findings suggest that the risk of childhood leukemia may be related to the combined effects of the static and ELF magnetic fields. Further tests of the hypothesis are proposed.
我们提出一个假说，即儿童白血病的风险与暴露于特定组合的静磁场和极低频（ELF）磁场有关。利用钙外流和硅藻迁移实验的实验室数据以及旋磁方程来预测60赫兹和静磁场的组合，这些组合被假定会增加白血病风险。实验室数据预测了静磁场强度的19个频段，带宽为9.1微特斯拉，这些频段与60赫兹磁场一起预计具有生物活性。然后，我们使用洛杉矶县一项病例对照研究的数据，评估了这种暴露指标与儿童白血病之间的关联。在从肿瘤登记处确定的124例病例和从朋友及随机数字拨号中抽取的99例对照的卧室中测量了ELF和静磁场。在这些受试者中，26例病例和20例对照暴露于静磁场中，静磁场位于以38.0微特斯拉和50.6微特斯拉为中心的预测生物活性频段内。虽然单独测量的ELF或静磁场与儿童白血病之间未发现关联，但在这些静磁场频段内的受试者中，随着测量的ELF磁场增加，白血病风险呈上升趋势（趋势P值 = 0.041）。对于暴露于推导频段内的静磁场且ELF磁场高于0.30微特斯拉的受试者，优势比（OR）为3.3 [95%置信区间（CI） = 0.4 - 30.5]（与暴露于频段外静磁场且ELF磁场低于0.07微特斯拉的受试者相比）。当根据Wertheimer - Leeper布线配置代码评估60赫兹磁场时，在假定的暴露条件下白血病风险再次更高（静磁场频段内极高电流配置的OR = 9.2；95% CI = 1.3 - 64.6）。尽管风险估计基于对少数受试者的有限磁场测量，但这些发现表明儿童白血病的风险可能与静磁场和ELF磁场的联合效应有关。我们提出了对该假说的进一步检验。
