Bunch K J, Swanson J, Vincent T J, Murphy M F G
Formerly Childhood Cancer Research Group, University of Oxford, New Richards Building, Old Road Campus, Headington, Oxford, OX3 7LG, UK. National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF, UK.
J Radiol Prot. 2015 Sep;35(3):695-705. doi: 10.1088/0952-4746/35/3/695. Epub 2015 Sep 7.
Epidemiological evidence of increased risks for childhood leukaemia from magnetic fields has implicated, as one source of such fields, high-voltage overhead lines. Magnetic fields are not the only factor that varies in their vicinity, complicating interpretation of any associations. Underground cables (UGCs), however, produce magnetic fields but have no other discernible effects in their vicinity. We report here the largest ever epidemiological study of high voltage UGCs, based on 52,525 cases occurring from 1962-2008, with matched birth controls. We calculated the distance of the mother's address at child's birth to the closest 275 or 400 kV ac or high-voltage dc UGC in England and Wales and the resulting magnetic fields. Few people are exposed to magnetic fields from UGCs limiting the statistical power. We found no indications of an association of risk with distance or of trend in risk with increasing magnetic field for leukaemia, and no convincing pattern of risks for any other cancer. Trend estimates for leukaemia as shown by the odds ratio (and 95% confidence interval) per unit increase in exposure were: reciprocal of distance 0.99 (0.95-1.03), magnetic field 1.01 (0.76-1.33). The absence of risk detected in relation to UGCs tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields.
流行病学证据表明，磁场会增加儿童患白血病的风险，其中一个磁场来源是高压架空线。磁场并非其附近唯一变化的因素，这使得对任何关联的解读变得复杂。然而，地下电缆（UGC）会产生磁场，但在其附近没有其他可察觉的影响。我们在此报告有史以来最大规模的关于高压UGC的流行病学研究，该研究基于1962年至2008年期间发生的52525例病例，并匹配了出生对照。我们计算了孩子出生时母亲住址到英格兰和威尔士最接近的275或400千伏交流或高压直流UGC的距离以及由此产生的磁场。很少有人暴露于UGC产生的磁场中，这限制了统计效力。我们没有发现白血病风险与距离有关联的迹象，也没有发现随着磁场增加风险呈趋势变化的迹象，对于任何其他癌症也没有令人信服的风险模式。白血病的趋势估计值（以优势比（及95%置信区间）表示）为每单位暴露增加量：距离的倒数为0.99（0.95 - 1.03），磁场为1.01（0.76 - 1.33）。与UGC相关未检测到风险这一情况，往往进一步支持了架空线的任何风险可能并非由磁场引起的观点。
