Light-at-night, circadian disruption and breast cancer: assessment of existing evidence
TLDR
If a consensus eventually emerges that LAN does increase risk, then the mechanisms for the effect are important to elucidate for intervention and mitigation and will provide for the development of lighting technologies at home and at work that minimize circadian disruption, while maintaining visual efficiency and aesthetics.Abstract:
Background Breast cancer incidence is increasing globally for largely unknown reasons. The possibility that a portion of the breast cancer burden might be explained by the introduction and increasing use of electricity to light the night was suggested >20 years ago.
Methods The theory is based on nocturnal light-induced disruption of circadian rhythms, notably reduction of melatonin synthesis. It has formed the basis for a series of predictions including that non-day shift work would increase risk, blind women would be at lower risk, long sleep duration would lower risk and community nighttime light level would co-distribute with breast cancer incidence on the population level.
Results Accumulation of epidemiological evidence has accelerated in recent years, reflected in an International Agency for Research on Cancer (IARC) classification of shift work as a probable human carcinogen (2A). There is also a strong rodent model in support of the light-at-night (LAN) idea.
Conclusion If a consensus eventually emerges that LAN does increase risk, then the mechanisms for the effect are important to elucidate for intervention and mitigation. The basic understanding of phototransduction for the circadian system, and of the molecular genetics of circadian rhythm generation are both advancing rapidly, and will provide for the development of lighting technologies at home and at work that minimize circadian disruption, while maintaining visual efficiency and aesthetics. In the interim, there are strategies now available to reduce the potential for circadian disruption, which include extending the daily dark period, appreciate nocturnal awakening in the dark, using dim red light for nighttime necessities, and unless recommended by a physician, not taking melatonin tablets.read more
Citations
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A retrospective cohort study of shift work and risk of incident cancer among German male chemical workers.
Mei Yong,Maria Blettner,Katharina Emrich,Michael Nasterlack,Christoph Oberlinner,Gaël P. Hammer +5 more
TL;DR: The authors' analyses do not provide evidence for a carcinogenic effect of the shift system under study, and the risks of leukemia and esophagus cancer were increased if smoking was not taken into account, albeit based on small numbers.
Journal ArticleDOI
Polymorphisms in circadian genes, night work and breast cancer: Results from the GENICA study
Sylvia Rabstein,Volker Harth,Christina Justenhoven,Beate Pesch,Sabine Plöttner,Evelyn Heinze,Anne Lotz,Christian Baisch,Markus Schiffermann,Hiltrud Brauch,Ute Hamann,Yon Ko,Thomas Brüning +12 more
TL;DR: The results of the population-based case-control study support a putative role of the CLOCK gene in the development of breast cancer in shift workers and higher order interaction analyses suggest a potential relevance of MTNR1B with the key transcriptional factor NPAS2 with ARNTL.
Journal ArticleDOI
Disruption of circadian rhythm increases the risk of cancer, metabolic syndrome and cardiovascular disease
TL;DR: This review discusses how a disruption of the “biological clock” or circadian rhythms could be involved in the development of these diseases as circadian rhythms control multiple physiological processes such as wake/sleep cycles, hormonal levels, body temperature, metabolism, and immune system.
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Functional interplay between melatonin receptor-mediated antiproliferative signaling and androgen receptor signaling in human prostate epithelial cells: potential implications for therapeutic strategies against prostate cancer.
TL;DR: It is demonstrated that melatonin inhibits the proliferation of LNCaP and VCaP prostate cancer cells via activation of the same MT1 receptor‐mediated antiproliferative signaling pathway.
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Review of the potential health effects of light and environmental exposures in underground workplaces
Ei Ei Khaing Nang,Gulifeiya Abuduxike,Pawel Posadzki,Ushashree Divakar,Nanthini Visvalingam,Nuraini Nazeha,Gerard Dunleavy,George I. Christopoulos,Chee Kiong Soh,Krister Järbrink,Michael Soljak,Josip Car +11 more
TL;DR: The literature on the range of possible environmental exposures, and the possible health effects, to identify future research directions was narratively reviewed to expand knowledge of the health effects of underground environments.
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