Shift Work and Breast Cancer

• Published in: International journal of environmental research and public health Vol. 17; no. 24; p. 9544
• Main Authors: Gehlert, Sarah, Clanton, Mark
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.12.2020; MDPI
• Subjects: Breast cancer; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Circadian Rhythm; Concept Paper; Disease; Epidemiology; Female; Genes; Humans; Light; Mammals; Medical research; Melatonin; Mortality; Shift work; Shift Work Schedule - adverse effects; Socioeconomic factors; Womens health; Work Schedule Tolerance; shift work; breast cancer; employment
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph17249544

The rates of shift work outside of daylight hours have increased in recent years, and nighttime shift work is now considered a potential carcinogenic occupational exposure. Light at night exposure, lower melatonin production, and the production of stress-related mediators disrupt normal sleep–wake cycles. Women who work lower-wage jobs and part-time workers whose shifts are determined entirely by their supervisors (rotating shifts) may be subject to stress related to efforts to align childcare and other needs with the unpredictable nature of rotating shift work. The causal link between breast cancer and the sleep cycle or circadian disruption are yet to be established; however, disruption of the circadian cycles by light at night exposure or chronic exposure to stress-related mediators have all been linked to the increased risk of breast cancer. We review the existing literature on shift work and breast cancer, identify knowledge gaps, and suggest future directions for research.