Department of Midwifery, School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Islamic Republic of Iran.
Department of Epidemiology, School of Health, Mashhad University of Medical Sciences, Mashhad, Islamic Republic of Iran.
BMC Womens Health. 2021 Mar 2;21(1):89. doi: 10.1186/s12905-021-01233-4.
The International Agency for Research on Cancer (IARC) has classified shift work as a possible human carcinogen. The results of systematic on this topic is contradictory. This systematic review and meta-analysis, therefore, aimed to update the current evidence regarding the relationship between night-shift work duration and breast cancer risk.
PubMed, Web of Science, and Scopus as well as reference list of included studies were searched until December 19, 2020. Observational case-control or cohort studies investigating the relationship between the duration of night-shift work and breast cancer in women were included, which all quantified night-shift work exposure. All statistical analyses were done by Stata version 11.2.
Our literature search was resulted in retrieval of 4854 publications from which 26 eligible studies with 1,313,348 participants were included in the meta-analyses. The pooled relative risk (RR) and 95% confidence intervals (CIs) of breast cancer for short-term night-shift workers (< 10 years) was 1.13 (95% CI 1.03-1.24, p = 0.008, I = 71.3%), and for long-term night-shift workers (≥ 10 years) was 1.08 (95% CI 0.99-1.17, p = 0.09, I = 42.2%), with moderate to substantial statistical heterogeneity observed in both analyses. The results of subgroup analysis showed that flight attendants with long overnight flights were at an elevated risk of breast cancer, but unmeasured confounders limited these results. The risk of breast cancer in case control studies, adjusted for reproductive factors and family history of breast cancer as well as studies with high quality was increased in both short term and long term night-shift workers.
This systematic review found a positive statistical relationship between night work and breast cancer risk in short-term night-shift workers but no increase was observed in the long-term night-shift workers.
国际癌症研究机构（IARC）已将轮班工作归类为可能的人类致癌物。关于这个主题的系统研究结果是矛盾的。因此，本系统综述和荟萃分析旨在更新关于夜班工作时间与乳腺癌风险之间关系的现有证据。
检索 PubMed、Web of Science 和 Scopus 以及纳入研究的参考文献列表，截至 2020 年 12 月 19 日。纳入了研究夜班工作时间与女性乳腺癌之间关系的观察性病例对照或队列研究，这些研究均量化了夜班工作暴露情况。所有统计分析均使用 Stata 版本 11.2 进行。
我们的文献检索共检索到 4854 篇文献，其中 26 项符合条件的研究共纳入 1313348 名参与者进行荟萃分析。短期夜班工人（<10 年）乳腺癌的合并相对风险（RR）和 95%置信区间（CI）为 1.13（95%CI 1.03-1.24，p=0.008，I=71.3%），长期夜班工人（≥10 年）为 1.08（95%CI 0.99-1.17，p=0.09，I=42.2%），两种分析均观察到中度至高度统计学异质性。亚组分析结果表明，长时间夜间飞行的空乘人员患乳腺癌的风险升高，但未测量的混杂因素限制了这些结果。在病例对照研究中，调整了生殖因素和乳腺癌家族史以及高质量的研究，短期和长期夜班工人的乳腺癌风险均增加。
本系统综述发现夜班工作与短期夜班工人的乳腺癌风险之间存在正统计学关系，但长期夜班工人中未观察到这种增加。
