Feychting M, Forssén U, Rutqvist L E, Ahlbom A
Institute of Environmental Medicine, Karolinska Institutet, stockholm, Sweden.
Epidemiology. 1998 Jul;9(4):392-7.
We conducted a case-control study to test the hypothesis that residential magnetic field exposures increase the incidence of breast cancer. The study was based on people who had lived within 300 m of 220- or 400-kV power lines in Sweden at any time between 1960 and 1985. We identified 699 cases of breast cancer in women and 9 cases in men. One matched control per female case and eight per male case were selected at random. Estrogen receptor information was available for a subset of female cases. We assessed magnetic field exposure through calculations of the magnetic fields generated by the power lines before diagnosis. For calculated magnetic field levels > or = 0.2 microtesla (microT) closest in times before diagnosis, we estimated the relative risk to be 1.0 [95% confidence interval (CI) = 0.7-1.5] for women and 2.1 (95% CI = 0.3-14.1) for men. Women younger than 50 years of age at diagnosis had a relative risk of 1.8 (95% CI = 0.7-4.3). For women with estrogen receptor-positive breast cancer, the relative risk was estimated at 1.6 (95% CI = 0.6-4.1), using the exposure cutoff point > or = 0.1 microT. Among estrogen receptor-positive women younger than 50 years at diagnosis, the relative risk increased to 7.4 (95% CI = 1.0-178.1).
我们进行了一项病例对照研究，以检验居住磁场暴露会增加乳腺癌发病率这一假设。该研究基于1960年至1985年期间曾在瑞典距离220千伏或400千伏输电线300米范围内居住过的人群。我们确定了699例女性乳腺癌病例和9例男性乳腺癌病例。为每例女性病例随机选取一名匹配对照，为每例男性病例随机选取八名匹配对照。部分女性病例可获取雌激素受体信息。我们通过计算诊断前输电线产生的磁场来评估磁场暴露情况。对于诊断前最近时段计算出的磁场水平≥0.2微特斯拉（μT）的情况，我们估计女性的相对风险为1.0[95%置信区间（CI）=0.7 - 1.5]，男性为2.1（95% CI = 0.3 - 14.1）。诊断时年龄小于50岁的女性相对风险为1.8（95% CI = 0.7 - 4.3）。对于雌激素受体阳性乳腺癌女性，使用暴露临界值≥0.1μT时，相对风险估计为1.6（95% CI = 0.6 - 4.1）。在诊断时年龄小于50岁的雌激素受体阳性女性中，相对风险增至7.4（95% CI = 1.0 - 178.1）。
