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Author Dumont, M.; Beaulieu, C. url  doi
openurl 
  Title Light exposure in the natural environment: relevance to mood and sleep disorders Type Journal Article
  Year 2007 Publication Sleep Medicine Abbreviated Journal Sleep Med  
  Volume 8 Issue 6 Pages 557-565  
  Keywords Human Health; Affect; *Biological Clocks; *Circadian Rhythm; Humans; *Light; Mood Disorders/*etiology; Sleep Disorders, Circadian Rhythm/*complications; Wakefulness; Work Schedule Tolerance  
  Abstract In addition to being necessary for vision, light also plays a primary role in circadian physiology. Humans are diurnal animals and their biological clock synchronizes their physiological functions in such a way that functions associated with activity happen in the daytime while functions associated with rest occur at night. A misalignment between the endogenous circadian clock and the desired sleep schedule is the main cause of circadian sleep disorders; it may be involved in certain mood disorders as well. Since light is the main environmental cue used by the biological clock to set its own timing in relation to the day-night cycle, inappropriate light exposure can be involved in the physiopathology of circadian disorders. Conversely, when handled properly, controlled light exposure can be used to treat some mood and sleep disorders. While the earliest studies in the field focused solely on exposure to bright light, contemporary studies aim at understanding how the entire profile of light-dark exposure can influence the circadian clock and, consequently, mood, sleep, and vigilance quality. Following a brief summary of the main concepts underlying the non-visual effects of light, this paper presents some studies using ambulatory measurements of light exposure to illustrate how these concepts apply in real-life situations and discusses the clinical relevance of light exposure in the natural environment for mood, sleep, and circadian disorders.  
  Address (up) Chronobiology Laboratory, Sacre-Coeur Hospital of Montreal, Montreal, Quebec, Canada H4J 1C5. marie.dumont@umontreal.ca  
  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 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17383230 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 736  
Permanent link to this record
 

 
Author Obayashi, K.; Yamagami, Y.; Kurumatani, N.; Saeki, K. url  doi
openurl 
  Title Bedroom lighting environment and incident diabetes mellitus: a longitudinal study of the HEIJO-KYO cohort Type Journal Article
  Year 2019 Publication Sleep Medicine Abbreviated Journal Sleep Medicine  
  Volume 65 Issue Pages 1-3  
  Keywords Human Health; Metabolic disorders; diabetes; geriatrics  
  Abstract Objectives

Light information received by the brain influences human circadian timing and metabolism; low-level light at night (LAN) significantly increased body mass and led to prediabetes in mice. We hypothesized that LAN exposure increases the diabetes risk in humans. The aim of the present study was to evaluate a longitudinal association between LAN exposure and the incidence of diabetes in a general population.

Methods

In our prospective cohort study, bedroom light intensity was measured at 1-min intervals in 678 elderly participants without diabetes at baseline. The average light intensity recorded between bedtimes and rise times over two consecutive nights was used in the analysis.

Results

During follow-up (median, 42 months), 19 of the 678 participants (mean age, 70.6 years) developed diabetes. Poisson regression models revealed that the incidence rate for diabetes was significantly higher in the LAN group (average ≥5 lux, N = 128) than the dark group (average <5 lux, N = 550) (incidence rate ratio, 3.74; 95% confidence interval (CI), 1.55–9.05; p=0.003). Further propensity score adjustments in relation to LAN produced consistent results (incidence rate ratio, 3.19; 95% CI, 1.38–7.35; p=0.007). When the cut-off value of LAN was decreased to 3 lux, the relationship remained significant (incidence rate ratio 2.74; 95% CI, 1.19–6.33; p=0.018).

Conclusions

Our findings suggest that LAN exposure increases the incidence of diabetes in a general elderly population. Further research involving a large cohort with new-onset diabetes is warranted to elucidate these findings.
 
  Address (up) Department of Epidemiology, Nara Medical University School of Medicine, 840 Shijocho, Kashiharashi, Nara, 634-8521, Japan; obayashi(at)naramed-u.ac.jp  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2605  
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Author Haus, E.L.; Smolensky, M.H. url  doi
openurl 
  Title Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation Type Journal Article
  Year 2013 Publication Sleep Medicine Reviews Abbreviated Journal Sleep Med Rev  
  Volume 17 Issue 4 Pages 273-284  
  Keywords Cell Cycle/physiology; Circadian Rhythm/*physiology; Epigenesis, Genetic/physiology; Humans; Light; Melatonin/physiology; Neoplasms/*etiology; Risk Factors; Sleep Deprivation/*complications; Work Schedule Tolerance/*physiology; oncogenesis  
  Abstract Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species.  
  Address (up) Department of Laboratory Medicine & Pathology, University of Minnesota and Health Partners Medical Group, Regions Hospital, 640 Jackson Street, St. Paul, Minnesota 55101, USA. Erhard.X.Haus@HealthPartners.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 1087-0792 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23137527 Approved no  
  Call Number IDA @ john @ Serial 157  
Permanent link to this record
 

 
Author Sharkey, K.M.; Carskadon, M.A.; Figueiro, M.G.; Zhu, Y.; Rea, M.S. url  doi
openurl 
  Title Effects of an advanced sleep schedule and morning short wavelength light exposure on circadian phase in young adults with late sleep schedules Type Journal Article
  Year 2011 Publication Sleep Medicine Abbreviated Journal Sleep Med  
  Volume 12 Issue 7 Pages 685-692  
  Keywords Affect/physiology/radiation effects; Circadian Rhythm/*physiology/*radiation effects; Color; Dose-Response Relationship, Radiation; Female; Humans; *Light; Male; Melatonin/metabolism; Photoperiod; Phototherapy/*methods; Saliva/metabolism; Sleep/physiology/radiation effects; Sleep Disorders, Circadian Rhythm/prevention & control/*therapy; Stress, Psychological/prevention & control/therapy; Treatment Outcome; Young Adult; blue light  
  Abstract OBJECTIVE: We examined the effects of an advanced sleep/wake schedule and morning short wavelength (blue) light in 25 adults (mean age+/-SD=21.8+/-3 years; 13 women) with late sleep schedules and subclinical features of delayed sleep phase disorder (DSPD). METHODS: After a baseline week, participants kept individualized, fixed, advanced 7.5-h sleep schedules for 6days. Participants were randomly assigned to groups to receive “blue” (470nm, approximately 225lux, n=12) or “dim” (<1lux, n=13) light for 1h after waking each day. Head-worn “Daysimeters” measured light exposure; actigraphs and sleep diaries confirmed schedule compliance. Salivary dim light melatonin onset (DLMO), self-reported sleep, and mood were examined with 2x2 ANOVA. RESULTS: After 6days, both groups showed significant circadian phase advances, but morning blue light was not associated with larger phase shifts than dim-light exposure. The average DLMO advances (mean+/-SD) were 1.5+/-1.1h in the dim light group and 1.4+/-0.7h in the blue light group. CONCLUSIONS: Adherence to a fixed advanced sleep/wake schedule resulted in significant circadian phase shifts in young adults with subclinical DSPD with or without morning blue light exposure. Light/dark exposures associated with fixed early sleep schedules are sufficient to advance circadian phase in young adults.  
  Address (up) Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Alpert Medical School of Brown University, Box G-RIH, Providence, RI 02912, USA. katherine_sharkey@brown.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 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21704557; PMCID:PMC3145013 Approved no  
  Call Number IDA @ john @ Serial 303  
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Author Joo, E.Y.; Abbott, S.M.; Reid, K.J.; Wu, D.; Kang, J.; Wilson, J.; Zee, P.C. url  doi
openurl 
  Title Timing of light exposure and activity in adults with delayed sleep-wake phase disorder Type Journal Article
  Year 2016 Publication Sleep Medicine Abbreviated Journal Sleep Med  
  Volume 32 Issue Pages 259-265  
  Keywords Human Health  
  Abstract OBJECTIVE: To characterize the patterns of light exposure and physical activity level and assess their relationship with sleep quality and depressive symptoms in adults with delayed sleep-wake phase disorder (DSWPD). METHODS: 42 DSWPD (22 female, mean age 34.5 y) and 26 (+/-4 years) age-and-sex-matched controls (12 female, mean age 33.4 y) underwent seven days of light and activity monitoring. RESULTS: Individuals with DSWPD had significantly delayed bed times and wake times, but similar sleep duration compared to controls. Subjective sleep quality (Pittsburgh Sleep Quality Index (PSQI)) was poorer in DSWPDs compared to controls. Those with DSWPD had significantly more activity and light exposure late at night (2:00-4:00) and significantly less activity and light exposure in the morning (8:00-11:00). Total 24 h levels of light and activity were not significantly different between DSWPD and controls. However, the DSWPD group had significantly more light exposure than controls 22 h after waking, during their sleep period. Later light exposure correlated with higher depression scores [Beck Depression Index (BDI)] and poorer sleep quality (PSQI). CONCLUSIONS: The light exposure patterns observed in DSWPD likely contribute to and perpetuate the chronically delayed sleep and wake phase in these patients. In addition, increased light exposure during the sleep period may also contribute to the poor sleep quality and mood disorders that are common in these individuals.  
  Address (up) Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: p-zee@northwestern.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 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:27964860 Approved no  
  Call Number LoNNe @ kyba @ Serial 1639  
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