University of Oxford, Childhood Cancer Research Group, Richards Building, Old Road Campus, Headington, Oxford OX3 7LG, UK.
Br J Cancer. 2010 Sep 28;103(7):1122-7. doi: 10.1038/sj.bjc.6605795.
Epidemiological evidence suggests that chronic low-intensity extremely-low-frequency magnetic-field exposure is associated with increased risk of childhood leukaemia; it is not certain the association is causal.
We report a national case-control study relating childhood cancer risk to the average magnetic field from high-voltage overhead power lines at the child's home address at birth during the year of birth, estimated using National Grid records. From the National Registry of Childhood Tumours, we obtained records of 28,968 children born in England and Wales during 1962-1995 and diagnosed in Britain under age 15. We selected controls from birth registers, matching individually by sex, period of birth, and birth registration district. No participation by cases or controls was required.
The estimated relative risk for each 0.2 μT increase in magnetic field was 1.14 (95% confidence interval 0.57 to 2.32) for leukaemia, 0.80 (0.43-1.51) for CNS/brain tumours, and 1.34 (0.84-2.15) for other cancers.
Although not statistically significant, the estimate for childhood leukaemia resembles results of comparable studies. Assuming causality, the estimated attributable risk is below one case per year. Magnetic-field exposure during the year of birth is unlikely to be the whole cause of the association with distance from overhead power lines that we previously reported.
流行病学证据表明，慢性低强度极低频磁场暴露与儿童白血病风险增加有关；但不能确定这种关联是否具有因果关系。
我们报告了一项全国性病例对照研究，该研究将儿童癌症风险与儿童出生当年家庭住址处的高压架空输电线的平均磁场相关联，该磁场是根据国家电网的记录来估计的。我们从国家儿童肿瘤登记处获得了 1962 年至 1995 年期间在英格兰和威尔士出生的 28968 名儿童的记录，以及在英国 15 岁以下确诊的儿童。我们从出生登记处选择了对照者，按照性别、出生时期和出生登记区进行个体匹配。不需要病例或对照者参与。
对于磁场每增加 0.2μT，白血病的估计相对风险为 1.14（95%置信区间为 0.57 至 2.32），中枢神经系统/脑肿瘤为 0.80（0.43 至 1.51），其他癌症为 1.34（0.84 至 2.15）。
尽管没有统计学意义，但白血病的估计值与类似研究的结果相似。假设存在因果关系，则估计的归因风险低于每年一例。出生当年的磁场暴露不太可能是我们之前报告的与架空输电线距离相关联的原因的全部。
