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Author Stevens, R.G.
Title Artificial lighting in the industrialized world: circadian disruption and breast cancer Type Journal Article
Year 2006 Publication Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 17 Issue 4 Pages 501-507
Keywords Human Health; Alcohol Drinking/adverse effects; Animals; Breast Neoplasms/*etiology; Chronobiology Disorders/*etiology/physiopathology; Circadian Rhythm; Developing Countries; Female; Humans; Lighting/*adverse effects; Melatonin/metabolism; Risk Factors; Suprachiasmatic Nucleus/physiopathology
Abstract (down) Breast cancer risk is high in industrialized societies, and increases as developing countries become more Westernized. The reasons are poorly understood. One possibility is circadian disruption from aspects of modern life, in particular the increasing use of electric power to light the night, and provide a sun-free environment during the day inside buildings. Circadian disruption could lead to alterations in melatonin production and in changing the molecular time of the circadian clock in the suprachiasmatic nuclei (SCN). There is evidence in humans that the endogenous melatonin rhythm is stronger for persons in a bright-day environment than in a dim-day environment; and the light intensity necessary to suppress melatonin at night continues to decline as new experiments are done. Melatonin suppression can increase breast tumorigenesis in experimental animals, and altering the endogenous clock mechanism may have downstream effects on cell cycle regulatory genes pertinent to breast tissue development and susceptibility. Therefore, maintenance of a solar day-aligned circadian rhythm in endogenous melatonin and in clock gene expression by exposure to a bright day and a dark night, may be a worthy goal. However, exogenous administration of melatonin in an attempt to achieve this goal may have an untoward effect given that pharmacologic dosing with melatonin has been shown to phase shift humans depending on the time of day it's given. Exogenous melatonin may therefore contribute to circadian disruption rather than alleviate it.
Address University of Connecticut Health Center, Farmington, CT 06030-6325, USA. bugs@neuron.uchc.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:16596303 Approved no
Call Number LoNNe @ kagoburian @ Serial 818
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Author Dickerman, B.; Liu, J.
Title Does current scientific evidence support a link between light at night and breast cancer among female night-shift nurses? Review of evidence and implications for occupational and environmental health nurses Type Journal Article
Year 2012 Publication Workplace Health & Safety Abbreviated Journal Workplace Health Saf
Volume 60 Issue 6 Pages 273-81; quiz 282
Keywords Human Health; Breast Neoplasms/*epidemiology/nursing; Chronobiology Disorders/*epidemiology/nursing; Education, Nursing, Continuing; Environmental Health; Evidence-Based Nursing; Female; Humans; Light; Night Care/*statistics & numerical data; *Occupational Health Nursing; Risk Factors; *Work Schedule Tolerance
Abstract (down) Breast cancer is increasingly prevalent in industrialized regions of the world, and exposure to light at night (LAN) has been proposed as a potential risk factor. Epidemiological observations have documented an increased breast cancer risk among female night-shift workers, and strong experimental evidence for this relationship has also been found in rodent models. Indirect support for the LAN hypothesis comes from studies involving blind women, sleep duration, bedroom light levels, and community nighttime light levels. This article reviews the literature, discusses possible mechanisms of action, and provides recommendations for occupational health nursing research, practice, and education. Research is needed to further explore the relationship between exposure to LAN and breast cancer risk and elucidate the mechanisms underlying this relationship before interventions can be designed for prevention and mitigation of breast cancer.
Address MultiCare Good Samaritan Hospital, Puyallup, WA, USA. barbra.dickerman@gmail.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2165-0799 ISBN Medium
Area Expedition Conference
Notes PMID:22658734 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 512
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Author Kloog, I.; Stevens, R.G.; Haim, A.; Portnov, B.A.
Title Nighttime light level co-distributes with breast cancer incidence worldwide Type Journal Article
Year 2010 Publication Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 21 Issue 12 Pages 2059-2068
Keywords Adult; Birth Rate; Breast Neoplasms/*epidemiology/etiology; Carcinoma/*epidemiology/etiology; Circadian Rhythm/*physiology; Cohort Studies; Electricity; Female; Humans; Incidence; *Light/adverse effects; Lighting; Photoperiod; Registries; Urban Population/statistics & numerical data; World Health; oncogenesis
Abstract (down) Breast cancer incidence varies widely among countries of the world for largely unknown reasons. We investigated whether country-level light at night (LAN) is associated with incidence. We compared incidence rates of five common cancers in women (breast, lung, colorectal, larynx, and liver), observed in 164 countries of the world from the GLOBOCAN database, with population-weighted country-level LAN, and with several developmental and environmental indicators, including fertility rate, per capita income, percent of urban population, and electricity consumption. Two types of regression models were used in the analysis: Ordinary Least Squares and Spatial Errors. We found a significant positive association between population LAN level and incidence rates of breast cancer. There was no such an association between LAN level and colorectal, larynx, liver, and lung cancers. A sensitivity test, holding other variables at their average values, yielded a 30-50% higher risk of breast cancer in the highest LAN exposed countries compared to the lowest LAN exposed countries. The possibility that under-reporting from the registries in the low-resource, and also low-LAN, countries created a spurious association was evaluated in several ways and shown not to account for the results. These findings provide coherence of the previously reported case-control and cohort studies with the co-distribution of LAN and breast cancer in entire populations.
Address Department of Natural Resources & Environmental Management, University of Haifa, 31905 Mount Carmel, Haifa, Israel
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:20680434 Approved no
Call Number IDA @ john @ Serial 160
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Author Wright, K.P.J.; Hull, J.T.; Czeisler, C.A.
Title Relationship between alertness, performance, and body temperature in humans Type Journal Article
Year 2002 Publication American Journal of Physiology. Regulatory, Integrative and Comparative Physiology Abbreviated Journal Am J Physiol Regul Integr Comp Physiol
Volume 283 Issue 6 Pages R1370-7
Keywords Human Health; Adult; Attention/*physiology; *Body Temperature; Circadian Rhythm/physiology; Cognition/*physiology; Female; Humans; Male; Memory/physiology; Reaction Time; Sleep/physiology; Time Factors; Wakefulness/physiology; NASA Discipline Regulatory Physiology; Non-NASA Center
Abstract (down) Body temperature has been reported to influence human performance. Performance is reported to be better when body temperature is high/near its circadian peak and worse when body temperature is low/near its circadian minimum. We assessed whether this relationship between performance and body temperature reflects the regulation of both the internal biological timekeeping system and/or the influence of body temperature on performance independent of circadian phase. Fourteen subjects participated in a forced desynchrony protocol allowing assessment of the relationship between body temperature and performance while controlling for circadian phase and hours awake. Most neurobehavioral measures varied as a function of internal biological time and duration of wakefulness. A number of performance measures were better when body temperature was elevated, including working memory, subjective alertness, visual attention, and the slowest 10% of reaction times. These findings demonstrate that an increased body temperature, associated with and independent of internal biological time, is correlated with improved performance and alertness. These results support the hypothesis that body temperature modulates neurobehavioral function in humans.
Address Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. kenneth.wright@colorado.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0363-6119 ISBN Medium
Area Expedition Conference
Notes PMID:12388468 Approved no
Call Number LoNNe @ kagoburian @ Serial 835
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Author Summa, K.C.; Vitaterna, M.H.; Turek, F.W.
Title Environmental perturbation of the circadian clock disrupts pregnancy in the mouse Type Journal Article
Year 2012 Publication PloS one Abbreviated Journal PLoS One
Volume 7 Issue 5 Pages e37668
Keywords Animals; Circadian Rhythm/*physiology; *Environment; Female; Locomotion/physiology; Mice; Mice, Inbred C57BL; Photoperiod; Pregnancy; Pregnancy Outcome; Reproduction/*physiology
Abstract (down) BACKGROUND: The circadian clock has been linked to reproduction at many levels in mammals. Epidemiological studies of female shift workers have reported increased rates of reproductive abnormalities and adverse pregnancy outcomes, although whether the cause is circadian disruption or another factor associated with shift work is unknown. Here we test whether environmental disruption of circadian rhythms, using repeated shifts of the light:dark (LD) cycle, adversely affects reproductive success in mice. METHODOLOGY/PRINCIPAL FINDINGS: Young adult female C57BL/6J (B6) mice were paired with B6 males until copulation was verified by visual identification of vaginal plug formation. Females were then randomly assigned to one of three groups: control, phase-delay or phase-advance. Controls remained on a constant 12-hr light:12-hr dark cycle, whereas phase-delayed and phase-advanced mice were subjected to 6-hr delays or advances in the LD cycle every 5-6 days, respectively. The number of copulations resulting in term pregnancies was determined. Control females had a full-term pregnancy success rate of 90% (11/12), which fell to 50% (9/18; p<0.1) in the phase-delay group and 22% (4/18; p<0.01) in the phase-advance group. CONCLUSIONS/SIGNIFICANCE: Repeated shifting of the LD cycle, which disrupts endogenous circadian timekeeping, dramatically reduces pregnancy success in mice. Advances of the LD cycle have a greater negative impact on pregnancy outcomes and, in non-pregnant female mice, require longer for circadian re-entrainment, suggesting that the magnitude or duration of circadian misalignment may be related to the severity of the adverse impact on pregnancy. These results explicitly link disruptions of circadian entrainment to adverse pregnancy outcomes in mammals, which may have important implications for the reproductive health of female shift workers, women with circadian rhythm sleep disorders and/or women with disturbed circadian rhythms for other reasons.
Address Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:22649550; PMCID:PMC3359308 Approved no
Call Number IDA @ john @ Serial 92
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