Gobba Fabriziomaria, Bargellini Annalisa, Scaringi Meri, Bravo Giulia, Borella Paola
Chair of Occupational Medicine, Department of Public Health Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41100, Modena (MO), Italy.
Sci Total Environ. 2009 Jan 15;407(3):1218-23. doi: 10.1016/j.scitotenv.2008.08.012. Epub 2008 Sep 19.
Extremely Low Frequency-Magnetic Fields (ELF-MF) are possible carcinogens to humans and some data suggest that they can act as promoters or progressors. Since NK cells play a major role in the control of cancer development, an adverse effect on ELF-MF on NK function has been hypothesized. We examined NK activity in 52 workers exposed to different levels of ELF-MF in various activities. Individual exposure was monitored during 3 complete work-shifts using personal dosimeters. Environmental exposure was also monitored. ELF-MF levels in the workers were expressed as Time-Weighted Average (TWA) values. NK activity was measured in peripheral blood lymphocytes (PBL). In the whole group the median occupational TWA was 0.21 microT. According to the TWA levels, workers were classified as low exposed (26 subjects, TWA < or =0.2 microT) and higher exposed workers (26 subjects; TWA >0.2 microT). In higher exposed workers, we observed a trend to reduce NK activity compared to low exposed, but the difference was not significant. Then we selected a subgroup of highest exposed workers (12 subjects; TWA >1 microT); no difference was observed between low and highest exposed subjects in the main personal variables. Considering both E:T ratios from 12:1 to 50:1 and Lytic Units, a significant reduction in NK activity was observed in the highest exposed workers compared to the low exposed. Multivariate analysis showed a significant negative correlation between exposure and LU, while no correlation was evidenced with other personal characteristics. ELF-MF are considered possible carcinogens, and existing data suggest that they can act as promoters. Due to the role of NK activity in host defence against cancer, the results obtained in this study in workers exposed to ELF-MF levels exceeding 1 microT are in agreement with this hypothesis, and support the need for further investigation in this field.
极低频磁场（ELF-MF）可能是人类致癌物，一些数据表明它们可作为促进剂或进展剂。由于自然杀伤（NK）细胞在控制癌症发展中起主要作用，因此推测ELF-MF对NK功能有不良影响。我们检测了52名从事不同活动、暴露于不同水平ELF-MF的工人的NK活性。使用个人剂量计在3个完整工作日期间监测个体暴露情况。同时也监测了环境暴露情况。工人的ELF-MF水平以时间加权平均值（TWA）表示。在外周血淋巴细胞（PBL）中测量NK活性。在整个研究组中，职业TWA的中位数为0.21微特斯拉。根据TWA水平，将工人分为低暴露组（26名受试者，TWA≤0.2微特斯拉）和高暴露组（26名受试者；TWA＞0.2微特斯拉）。在高暴露组工人中，与低暴露组相比，我们观察到NK活性有降低的趋势，但差异不显著。然后我们选择了一组暴露水平最高的工人（12名受试者；TWA＞1微特斯拉）；在主要个人变量方面，低暴露组和高暴露组受试者之间未观察到差异。考虑到效应细胞与靶细胞比例从12:1至50:1以及溶解单位，与低暴露组相比，高暴露组工人的NK活性显著降低。多变量分析显示暴露与溶解单位之间存在显著负相关，而与其他个人特征未显示相关性。ELF-MF被认为是可能的致癌物，现有数据表明它们可作为促进剂。由于NK活性在宿主抗癌防御中的作用，本研究中暴露于超过1微特斯拉ELF-MF水平的工人所获得的结果与这一假设一致，并支持在该领域进行进一步研究的必要性。
