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Author Stevens, R.G.; Zhu, Y.
Title Electric light, particularly at night, disrupts human circadian rhythmicity: is that a problem? Type Journal Article
Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci
Volume 370 Issue Pages (down) 20140120
Keywords Human Health; circadian disruption; breast cancer; circadian genes; artificial light at night; iron
Abstract Over the past 3 billion years, an endogenous circadian rhythmicity has developed in almost all life forms in which daily oscillations in physiology occur. This allows for anticipation of sunrise and sunset. This physiological rhythmicity is kept at precisely 24 h by the daily cycle of sunlight and dark. However, since the introduction of electric lighting, there has been inadequate light during the day inside buildings for a robust resetting of the human endogenous circadian rhythmicity, and too much light at night for a true dark to be detected; this results in circadian disruption and alters sleep/wake cycle, core body temperature, hormone regulation and release, and patterns of gene expression throughout the body. The question is the extent to which circadian disruption compromises human health, and can account for a portion of the modern pandemics of breast and prostate cancers, obesity, diabetes and depression. As societies modernize (i.e. electrify) these conditions increase in prevalence. There are a number of promising leads on putative mechanisms, and epidemiological findings supporting an aetiologic role for electric lighting in disease causation. These include melatonin suppression, circadian gene expression, and connection of circadian rhythmicity to metabolism in part affected by haem iron intake and distribution.
Address Department of Community Medicine, University of Connecticut Health Center, Farmington, CT, USA; bugs@uchc.edu
Corporate Author Thesis
Publisher Royal Society Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1118
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Author Haim, A.; Zubidat, A.E.
Title Artificial light at night: melatonin as a mediator between the environment and epigenome Type Journal Article
Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci
Volume 370 Issue Pages (down) 20140121
Keywords Human Health; melatonin; epigenetic modifications; epigenetics; epigenome; light pollution; breast cancer; oncogenesis; tumorigenesis; biomarkers
Abstract The adverse effects of excessive use of artificial light at night (ALAN) are becoming increasingly evident and associated with several health problems including cancer. Results of epidemiological studies revealed that the increase in breast cancer incidents co-distribute with ALAN worldwide. There is compiling evidence that suggests that melatonin suppression is linked to ALAN-induced cancer risks, but the specific genetic mechanism linking environmental exposure and the development of disease is not well known. Here we propose a possible genetic link between environmental exposure and tumorigenesis processes. We discuss evidence related to the relationship between epigenetic remodelling and oncogene expression. In breast cancer, enhanced global hypomethylation is expected in oncogenes, whereas in tumour suppressor genes local hypermethylation is recognized in the promoter CpG chains. A putative mechanism of action involving epigenetic modifications mediated by pineal melatonin is discussed in relation to cancer prevalence. Taking into account that ALAN-induced epigenetic modifications are reversible, early detection of cancer development is of great significance in the treatment of the disease. Therefore, new biomarkers for circadian disruption need to be developed to prevent ALAN damage.
Address The Israeli Center for Interdisciplinary Research in Chronobiology, Department of Evolutionary and Environmental Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel; ahaim@research.haifa.ac.il
Corporate Author Thesis
Publisher Royal Society Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1119
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Author Jones, T.M.; Durrant, J; Michaelides, E.B.; Green, M.C., M.P.
Title Melatonin: a possible link between the presence of artificial light at night and reductions in biological fitness Type Journal Article
Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci
Volume 370 Issue Pages (down) 20140122
Keywords Human Health
Abstract The mechanisms underpinning the ecological impacts of the presence of artificial night lighting remain elusive. One suspected underlying cause is that the presence of light at night (LAN) supresses nocturnal production of melatonin, a key driver of biological rhythm and a potent antioxidant with a proposed role in immune function. Here, we briefly review the evidence for melatonin as the link between LAN and changes in behaviour and physiology. We then present preliminary data supporting the potential for melatonin to act as a recovery agent mitigating the negative effects of LAN in an invertebrate. Adult crickets (Teleogryllus commodus), exposed to constant illumination, were provided with dietary melatonin (concentrations: 0, 10 or 100 µg ml−1) in their drinking water. We then compared survival, lifetime fecundity and, over a 4-week period, immune function (haemocyte concentration, lysozyme-like and phenoloxidase (PO) activity). Melatonin supplementation was able only partially to mitigate the detrimental effects of LAN: it did not improve survival or fecundity or PO activity, but it had a largely dose-dependent positive effect on haemocyte concentration and lysozyme-like activity. We discuss the implications of these relationships, as well as the usefulness of invertebrates as model species for future studies that explore the effects of LAN.
Address Department of Zoology, The University of Melbourne, 3010 VIC, Australia; theresa@unimelb.edu.au
Corporate Author Thesis
Publisher Royal Society Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1120
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Author Obayashi, K.; Saeki, K.; Kurumatani, N.
Title Ambient Light Exposure and Changes in Obesity Parameters: A Longitudinal Study of the HEIJO-KYO Cohort Type Journal Article
Year 2016 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume Issue Pages (down) jc20154123
Keywords Human Health
Abstract CONTEXT: Previous epidemiological studies have suggested an association between nighttime light levels and the prevalence of obesity, although evidence is limited to cross-sectional studies. OBJECTIVE: To evaluate the longitudinal association between ambient light exposure and the subsequent changes in obesity parameters. DESIGN AND PARTCIPANTS: Data from 1,110 elderly participants at baseline (mean age, 71.9 years) and data from 766 at follow-up (median, 21 months) were included in this prospective population-based study. MEASURES: Time-dependent ambient light exposure based on objective measurements and changes in the waist-to-height ratio (WHtR) and body mass index (BMI) were measured. RESULTS: Multivariable mixed-effect linear regression models showed a significant association between light exposure and the %WHtR gain; this was independent of potential confounders (e.g., caloric intake, physical activity, and sleep/wake parameters). Nighttime or evening exposure to higher light intensity was significantly associated with subsequent %WHtR gain. Morning exposure to a longer time >/=500 lux or nighttime exposure to a longer time <3 lux was significantly associated with subsequent %WHtR loss. These association trends were nearly consistent when the BMI was used as an obesity parameter. Increased nighttime light exposure (mean >/=3 vs. <3 lux) was estimated to correspond to a 10.2% WHtR gain and 10.0% increase in BMI over 10 years. CONCLUSIONS: Ambient light exposure, such as increased nighttime or evening light exposure and decreased morning light exposure, was independently associated with subsequent increases in obesity parameters. Further interventional studies are warranted to establish an optimal controlled lighting environment as a preventive option against obesity.
Address Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara, Japan
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 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:27383113 Approved no
Call Number LoNNe @ kyba @ Serial 1483
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Author Swaminathan, K.; Klerman, E.B.; Phillips, A.J.K.
Title Are Individual Differences in Sleep and Circadian Timing Amplified by Use of Artificial Light Sources? Type Journal Article
Year 2017 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume Issue Pages (down) 748730417699310
Keywords Human Health
Abstract Within the human population, there is large interindividual variability in the timing of sleep and circadian rhythms. This variability has been attributed to individual differences in sleep physiology, circadian physiology, and/or light exposure. Recent experimental evidence suggests that the latter is necessary to evoke large interindividual differences in sleep and circadian timing. We used a validated model of human sleep and circadian physiology to test the hypothesis that intrinsic differences in sleep and circadian timing are amplified by self-selected use of artificial light sources. We tested the model under 2 conditions motivated by an experimental study (Wright et al., 2013): (1) a “natural” light cycle, and (2) a “realistic” light cycle that included attenuation of light due to living indoors when natural light levels are high and use of electric light when natural light levels are low. Within these conditions, we determined the relationship between intrinsic circadian period (within the range of 23.7-24.6 h) and timing of sleep onset, sleep offset, and circadian rhythms. In addition, we simulated a work week, with fixed wake time for 5 days and free sleep times on weekends. Under both conditions, a longer intrinsic period resulted in later sleep and circadian timing. Compared to the natural condition, the realistic condition evoked more than double the variation in sleep timing across the physiological range of intrinsic circadian periods. Model predictions closely matched data from the experimental study. We found that if the intrinsic circadian period was long (>24.2 h) under the realistic condition, there was significant mismatch in sleep timing between weekdays and weekends, which is known as social jetlag. These findings indicate that individual tendencies to have very delayed schedules can be greatly amplified by self-selected modifications to the natural light/dark cycle. This has important implications for therapeutic treatment of advanced or delayed sleep phase disorders.
Address School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
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 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:28367676 Approved no
Call Number SU @ spitschan @ Serial 1648
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