Research Center on Environmental Health and Occupational Health, School of Public Health, Université Libre de Bruxelles, CP 593, Route de Lennik 808, 1070, Brussels, Belgium.
J Appl Toxicol. 2012 Dec;32(12):952-8. doi: 10.1002/jat.2761. Epub 2012 Jun 14.
The so-called 'Melatonin Hypothesis' proposed that decreased nocturnal production of melatonin (MLT) might explain the increased risk of breast cancer that has been formerly attributed to extremely low-frequency (ELF) magnetic fields (MF) of weak intensity. Although the risk of ELF MF upon breast cancer was later dismissed, repeated reports were published of partial inhibition of MLT secretion in rats under long-term (≥ 4 weeks) exposure to weak ELF MF. Since 2004, however, this topic has not been experimentally studied any more. In the present study, we propose to go back to the MLT hypothesis and apply it to childhood leukemia, for which an increased risk has been robustly associated with residential exposure to ELF MF. Contrary to the original hypothesis, however, we do not consider decreased MLT levels, but disruption of circadian rhythmicity per se as the effector mechanism. Indeed, the role of the circadian timing system in the development of childhood leukemia has been well established. Motivation for going back to the MLT hypothesis comes from recent data that suggest magnetosensory disruption by ELF MF in mammals, and magnetosensitivity in humans, together with current evidence for an influence on circadian rhythmicity from disruption of non-photic sensory stimuli of various natures. We thus suggest further study on circadian rhythmicity in humans (children if possible) under long-term exposure to weak ELF MF.
所谓的“褪黑素假说”提出，夜间褪黑素（MLT）生成减少可能解释了以前归因于极低频（ELF）磁场（MF）的弱强度的乳腺癌风险增加。尽管 ELF MF 对乳腺癌的风险后来被否定，但仍有重复报道称，大鼠在长期（≥ 4 周）暴露于弱 ELF MF 下，MLT 分泌受到部分抑制。然而，自 2004 年以来，这个话题就没有再进行过实验研究。在本研究中，我们提议回到 MLT 假说，并将其应用于儿童白血病，因为已经有强有力的证据表明，儿童白血病的风险与居住环境中接触 ELF MF 有关。然而，与原始假说相反，我们不考虑 MLT 水平降低，而是本身就考虑昼夜节律的中断作为效应机制。事实上，昼夜节律计时系统在儿童白血病的发展中的作用已经得到了很好的证实。回到 MLT 假说的动机来自最近的数据，这些数据表明 ELF MF 在哺乳动物中对磁感觉的干扰，以及人类的磁敏感性，以及目前有证据表明，各种性质的非光感觉刺激的中断会对昼夜节律产生影响。因此，我们建议对人类（如果可能的话，儿童）在长期暴露于弱 ELF MF 下的昼夜节律进行进一步研究。
