Savitz D A
Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599, USA.
Environ Health Perspect. 1995 Mar;103 Suppl 2(Suppl 2):69-74. doi: 10.1289/ehp.95103s269.
For over ten years, there has been concern with the potential for increased risk of cancer among "electrical workers." In contrast to studies of residential exposure to magnetic fields, occupational studies include electric and magnetic field exposures and have much greater variability in field intensity, frequency, and temporal patterns. Studies of leukemia in electrical workers show a moderate consistency, with elevated risk ratios of 1.2 to 2.0 commonly observed. Brain tumors are similarly elevated with some consistency, and three recent studies have suggested increased risk of male breast cancer. Retrospective exposure assessment methods were advanced in recent studies of diverse occupations in a study in central Sweden, which yielded evidence of increased risk of chronic lymphocytic leukemia among men in more highly exposed occupations. A study of telephone workers in New York State incorporated measurements and found some indication of increased leukemia risk only when exposures were based on historical technology. Utility workers in southern California were studied and found not to have increased risks of leukemia and brain cancer based on exposures estimated with measurements. An ongoing study of electric utility workers at five companies in the United States incorporates an extensive measurement protocol. Randomly selected workers within occupational categories wore a time-integrating magnetic-field meter to provide estimates of exposure for the occupational category. We were able to estimate and partition the variance into between-day (the largest contributor), within occupational categories, and between occupational categories. Principal research needs concern optimal levels of worker aggregation for exposure assignment, historical extrapolation, study of diverse work environments, and integration of residential and occupational exposure in the same study.
十多年来，人们一直担心“电气工人”患癌症的风险可能增加。与关于住宅磁场暴露的研究不同，职业研究涵盖了电场和磁场暴露，并且在场强、频率和时间模式方面具有更大的变异性。对电气工人白血病的研究显示出一定程度的一致性，通常观察到风险比在1.2至2.0之间升高。脑肿瘤也有类似程度的升高，最近的三项研究表明男性乳腺癌风险增加。在瑞典中部的一项针对不同职业的研究中，回顾性暴露评估方法在近期研究中得到了改进，该研究得出证据表明，从事暴露程度更高职业的男性患慢性淋巴细胞白血病的风险增加。纽约州对电话工人的一项研究进行了测量，结果发现只有在基于历史技术进行暴露评估时，才有一些白血病风险增加的迹象。对南加州公用事业工人的研究发现，根据测量估计的暴露情况，他们患白血病和脑癌的风险并未增加。美国正在对五家公司的电力公司工人进行一项研究，该研究采用了广泛的测量方案。在职业类别中随机挑选的工人佩戴时间积分磁场计，以提供该职业类别的暴露估计值。我们能够估计方差并将其划分为日间（最大贡献者）、职业类别内和职业类别间的方差。主要的研究需求涉及暴露分配的最佳工人聚集水平、历史推断、对不同工作环境的研究以及在同一研究中整合住宅和职业暴露。
