Circadian disruption, shift work and the risk of cancer: A summary of the evidence and studies in Seattle
Circadian disruption, shift work and the risk of cancer: A summary of the evidence and studies in Seattle
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DOI：
10.1007/s10552-005-9010-9
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发表时间：
2006-05-01
影响因子：
2.3
通讯作者：
Mirick, DK
中科院分区：
文献类型：
--
作者：
Davis, S;Mirick, DK
人们越来越感兴趣的可能性，破坏正常的昼夜节律可能会增加患癌症的风险。从事夜班工作的人可能会表现出夜间褪黑激素水平和生殖激素水平的改变，这可能会增加患乳腺癌等与乳腺癌有关的疾病的风险。流行病学研究现在开始出现，表明在夜间工作的妇女，以及经历睡眠剥夺，昼夜节律紊乱和夜间暴露在光线下的妇女患乳腺癌的风险增加，可能还有结肠直肠癌。最近在西雅图进行了几项研究，以调查可能扰乱昼夜节律并改变与乳腺癌病因相关的褪黑激素和生殖激素的正常夜间产生的因素的影响。迄今为止完成的研究发现：（1）乳腺癌的风险增加与夜间暴露于光线和夜班工作的指标有关;（2）夜间尿液中6-硫酸基褪黑激素水平降低与同一晚在卧室暴露于60 Hz磁场有关，以及许多其他因素，包括白天的时间，季节，饮酒量和体重指数。最近完成的是一项实验交叉研究，旨在调查是否暴露于60 Hz磁场在家庭睡眠环境中的受控条件下与夜间尿中6-硫酸氧褪黑激素浓度的降低，以及在一个样本的健康育龄妇女的尿中促黄体激素，促卵泡激素和雌二醇浓度的增加。目前正在进行一项研究，以确定夜间工作是否与尿中6-硫酸基褪黑激素水平降低有关，以及在育龄健康女性样本中上述生殖激素的尿浓度增加，并阐明与所确定的激素模式有关的夜班工人的睡眠特征。目前正在审查一项建议，将这些研究扩展到健康男性样本，以调查夜间工作是否与尿中6-硫酸基褪黑激素水平降低、尿皮质醇和可的松浓度升高、尿中一些雄激素代谢物水平升高以及血清中一些生殖激素浓度升高有关。其次，这项研究将阐明夜班工人的睡眠特征，这些特征与所确定的激素模式有关，并调查被认为调节人类生物钟的基因多态性是否与适应夜班工作的能力有关。预计这些研究将提高我们对昼夜节律紊乱在癌症病因学中的作用的理解。
There is increasing interest in the possibility that disruption of normal circadian rhythm may increase the risk of developing cancer. Persons who engage in nightshift work may exhibit altered nighttime melatonin levels and reproductive hormone profiles that could increase the risk of hormone-related diseases, including breast cancer. Epidemiologic studies are now beginning to emerge suggesting that women who work at night, and who experience sleep deprivation, circadian disruption, and exposure to light-at-night are at an increased risk of breast cancer, and possibly colorectal cancer as well. Several studies have been conducted in Seattle recently to investigate the effects of factors that can disrupt circadian rhythm and alter normal nocturnal production of melatonin and reproductive hormones of relevance to breast cancer etiology. Studies completed to date have found: (1) an increased risk of breast cancer associated with indicators of exposure to light-at-night and night shift work; and (2) decreased nocturnal urinary levels of 6-sulphatoxymelatonin associated with exposure to 60-Hz magnetic fields in the bedroom the same night, and a number of other factors including hours of daylight, season, alcohol consumption and body mass index. Recently completed is an experimental crossover study designed to investigate whether exposure to a 60-Hz magnetic field under controlled conditions in the home sleeping environment is associated with a decrease in nocturnal urinary concentration of 6-sulphatoxymelatonin, and an increase in the urinary concentration of luteinizing hormone, follicle stimulating hormone, and estradiol in a sample of healthy women of reproductive age. Presently underway is a study to determine whether working at night is associated with decreased levels of urinary 6-sulphatoxymelatonin, and increased urinary concentrations of the reproductive hormones listed above in a sample of healthy women of reproductive age, and to elucidate characteristics of sleep among night shift workers that are related to the hormone patterns identified. A proposal is under review to extend these studies to a sample of healthy men to investigate whether working at night is associated with decreased levels of urinary 6-sulphatoxymelatonin, and increased concentrations of urinary cortisol and cortisone, urinary levels of a number of androgen metabolites, and serum concentrations of a number of reproductive hormones. Secondarily, the proposed study will elucidate characteristics of sleep among night shift workers that are related to the hormone patterns identified, as well as investigate whether polymorphisms of the genes thought to regulate the human circadian clock are associated with the ability to adapt to night shift work. It is anticipated that collectively these studies will enhance our understanding of the role of circadian disruption in the etiology of cancer.