Schernhammer E S, Laden F, Speizer F E, Willett W C, Hunter D J, Kawachi I, Colditz G A
E. S. Schernhammer, Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
J Natl Cancer Inst. 2001 Oct 17;93(20):1563-8. doi: 10.1093/jnci/93.20.1563.
Melatonin shows potential oncostatic action, and light exposure during night suppresses melatonin production. There is little information, however, about the direct effect of night work on the risk of cancer. We investigated the effect of night work in breast cancer.
We examined the relationship between breast cancer and working on rotating night shifts during 10 years of follow-up in 78 562 women from the Nurses' Health Study. Information was ascertained in 1988 about the total number of years during which the nurses had worked rotating night shifts with at least three nights per month. From June 1988 through May 1998, we documented 2441 incident breast cancer cases. Logistic regression models were used to calculate relative risks (RRs) and 95% confidence intervals (CIs), adjusted for confounding variables and breast cancer risk factors. All statistical tests were two-sided.
We observed a moderate increase in breast cancer risk among the women who worked 1-14 years or 15-29 years on rotating night shifts (multivariate adjusted RR = 1.08 [95% CI = 0.99 to 1.18] and RR = 1.08 [95% CI = 0.90 to 1.30], respectively). The risk was further increased among women who worked 30 or more years on the night shift (RR = 1.36; 95% CI = 1.04 to 1.78). The test for trend was statistically significant (P =.02).
Women who work on rotating night shifts with at least three nights per month, in addition to days and evenings in that month, appear to have a moderately increased risk of breast cancer after extended periods of working rotating night shifts.
褪黑素显示出潜在的抑癌作用，夜间暴露于光线下会抑制褪黑素的分泌。然而，关于夜班工作对癌症风险的直接影响，相关信息较少。我们调查了夜班工作对乳腺癌的影响。
我们在护士健康研究中对78562名女性进行了10年的随访，研究乳腺癌与从事轮班夜班工作之间的关系。1988年确定了护士从事每月至少三个夜班的轮班夜班工作的总年数。从1988年6月到1998年5月，我们记录了2441例新发乳腺癌病例。使用逻辑回归模型计算相对风险（RRs）和95%置信区间（CIs），并对混杂变量和乳腺癌风险因素进行了调整。所有统计检验均为双侧检验。
我们观察到，从事1 - 14年或15 - 29年轮班夜班工作的女性患乳腺癌的风险有适度增加（多变量调整后的RR分别为1.08 [95% CI = 0.99至1.18]和RR = 1.08 [95% CI = 0.90至1.30]）。从事30年及以上夜班工作的女性风险进一步增加（RR = 1.36；95% CI = 1.04至1.78）。趋势检验具有统计学意义（P =.02）。
除了当月的白班和晚班外，每月至少从事三个夜班的轮班夜班工作的女性，在长期从事轮班夜班工作后，患乳腺癌的风险似乎有适度增加。
