Long-Term Nightshift Work and Breast Cancer Risk: An Updated Systematic Review and Meta-Analysis with Special Attention to Menopausal Status and to Recent Nightshift Work
MetadataShow full item record
Nightshift workBreast cancerRecent exposureMeta-analysisMenopausal statusOccupational exposureRetirement age
Schwarz, C.; Pedraza-Flechas, A.M.; Pastor-Barriuso, R.; Lope, V.; de Larrea, N.F.; Jiménez-Moleón, J.J.; Pollán, M.; Pérez-Gómez, B. Long-Term Nightshift Work and Breast Cancer Risk: An Updated Systematic Review and Meta-Analysis with Special Attention to Menopausal Status and to Recent Nightshift Work. Cancers 2021, 13, 5952. [https://doi.org/10.3390/cancers13235952]
This systematic review discusses long-term NSW and female BC risk, with special attention to differences between pre-and postmenopausal BC, to test the association with recent NSW. The review follows PRISMA guidelines (Prospero registry: CRD42018102515). We searched PubMed, Embase, and WOS for case–control, nested case–control, and cohort studies addressing long-term NSW (≥15 years) as risk exposure and female BC as outcome until 31 December 2020. Risk of bias was evaluated with the Newcastle–Ottawa scale. Eighteen studies were finally in-cluded (eight cohorts; five nested case–control; five case–control). We performed meta-analyses on long-term NSW and BC risk; overall and by menopausal status; a subanalysis on recent long-term NSW, based on studies involving predominantly women below retirement age; and a dose– response meta-analysis on NSW duration. The pooled estimate for long-term NSW and BC was 1.13 (95%CI = 1.01–1.27; 18 studies, I2 = 56.8%, p = 0.002). BC risk increased 4.7% per 10 years of NSW (95%CI = 0.94–1.09; 16 studies, I2 = 33.4%, p = 0.008). The pooled estimate for premenopausal BC was 1.27 (95%CI = 0.96–1.68; six studies, I2 = 32.0%, p = 0.196) and for postmenopausal BC 1.05 (95%CI = 0.90–1.24, I2 = 52.4%; seven studies, p = 0.050). For recent long-term exposure, the pooled estimate was 1.23 (95%CI = 1.06–1.42; 15 studies; I2 = 48.4%, p = 0.018). Our results indicate that long-term NSW increases the risk for BC and that menopausal status and time since exposure might be relevant.