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Author Gooley, J.J.; Chamberlain, K.; Smith, K.A.; Khalsa, S.B.S.; Rajaratnam, S.M.W.; Van Reen, E.; Zeitzer, J.M.; Czeisler, C.A.; Lockley, S.W.
Title Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans Type Journal Article
Year 2011 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume 96 Issue 3 Pages E463-72
Keywords (up) Adolescent; Adult; Female; Humans; *Light; *Lighting; Male; Melatonin/*blood; Sleep/physiology; Time Factors; Young Adult
Abstract CONTEXT: Millions of individuals habitually expose themselves to room light in the hours before bedtime, yet the effects of this behavior on melatonin signaling are not well recognized. OBJECTIVE: We tested the hypothesis that exposure to room light in the late evening suppresses the onset of melatonin synthesis and shortens the duration of melatonin production. DESIGN: In a retrospective analysis, we compared daily melatonin profiles in individuals living in room light (<200 lux) vs. dim light (<3 lux). PATIENTS: Healthy volunteers (n = 116, 18-30 yr) were recruited from the general population to participate in one of two studies. SETTING: Participants lived in a General Clinical Research Center for at least five consecutive days. INTERVENTION: Individuals were exposed to room light or dim light in the 8 h preceding bedtime. OUTCOME MEASURES: Melatonin duration, onset and offset, suppression, and phase angle of entrainment were determined. RESULTS: Compared with dim light, exposure to room light before bedtime suppressed melatonin, resulting in a later melatonin onset in 99.0% of individuals and shortening melatonin duration by about 90 min. Also, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50% in most (85%) trials. CONCLUSIONS: These findings indicate that room light exerts a profound suppressive effect on melatonin levels and shortens the body's internal representation of night duration. Hence, chronically exposing oneself to electrical lighting in the late evening disrupts melatonin signaling and could therefore potentially impact sleep, thermoregulation, blood pressure, and glucose homeostasis.
Address Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, Massachusetts 02115, USA. gmsjjg@nus.edu
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Series Editor Series Title Abbreviated Series Title
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ISSN 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:21193540; PMCID:PMC3047226 Approved no
Call Number IDA @ john @ Serial 139
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Author Martinez-Nicolas, A.; Ortiz-Tudela, E.; Madrid, J.A.; Rol, M.A.
Title Crosstalk between environmental light and internal time in humans Type Journal Article
Year 2011 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 28 Issue 7 Pages 617-629
Keywords (up) Adolescent; Biological Clocks/*physiology; Circadian Rhythm/*physiology; Cues; *Environment; Female; Humans; *Light; Male; Sleep; Spain; Temperature; *Time; Young Adult
Abstract Daily exposure to environmental light is the most important zeitgeber in humans, and all studied characteristics of light pattern (timing, intensity, rate of change, duration, and spectrum) influence the circadian system. However, and due to lack of current studies on environmental light exposure and its influence on the circadian system, the aim of this work is to determine the characteristics of a naturalistic regimen of light exposure and its relationship with the functioning of the human circadian system. Eighty-eight undergraduate students (18-23 yrs) were recruited in Murcia, Spain (latitude 38 degrees 01'N) to record wrist temperature (WT), light exposure, and sleep for 1 wk under free-living conditions. Light-exposure timing, rate of change, regularity, intensity, and contrast were calculated, and their effects on the sleep pattern and WT rhythm were then analyzed. In general, higher values for interdaily stability, relative amplitude, mean morning light, and light quality index (LQI) correlated with higher interdaily stability and relative amplitude, and phase advance in sleep plus greater stability in WT and phase advance of the WT circadian rhythm. On the other hand, a higher fragmentation of the light-exposure rhythm was associated with more fragmented sleep. Naturalistic studies using 24-h ambulatory light monitoring provide essential information about the main circadian system input, necessary for maintaining healthy circadian tuning. Correcting light-exposure patterns accordingly may help prevent or even reverse health problems associated with circadian disruption.
Address Chronobiology Laboratory, Department of Physiology, University of Murcia, Murcia, Spain
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:21793693 Approved no
Call Number IDA @ john @ Serial 302
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Author Taillard, J.; Capelli, A.; Sagaspe, P.; Anund, A.; Akerstedt, T.; Philip, P.
Title In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial Type Journal Article
Year 2012 Publication PloS one Abbreviated Journal PLoS One
Volume 7 Issue 10 Pages e46750
Keywords (up) Adult; *Automobile Driving; Caffeine/pharmacology; Coffee/chemistry; Cross-Over Studies; Double-Blind Method; Fatigue/*prevention & control; Humans; Light; Male; Middle Aged; *Photic Stimulation; Placebos; Psychomotor Performance/drug effects/radiation effects; Reproducibility of Results; Sleep Deprivation; Sleep Stages/radiation effects; Wakefulness/drug effects/physiology/*radiation effects; blue light
Abstract Prolonged wakefulness greatly decreases nocturnal driving performance. The development of in-car countermeasures is a future challenge to prevent sleep-related accidents. The aim of this study is to determine whether continuous exposure to monochromatic light in the short wavelengths (blue light), placed on the dashboard, improves night-time driving performance. In this randomized, double-blind, placebo-controlled, cross-over study, 48 healthy male participants (aged 20-50 years) drove 400 km (250 miles) on motorway during night-time. They randomly and consecutively received either continuous blue light exposure (GOLite, Philips, 468 nm) during driving or 2*200 mg of caffeine or placebo of caffeine before and during the break. Treatments were separated by at least 1 week. The outcomes were number of inappropriate line crossings (ILC) and mean standard deviation of the lateral position (SDLP). Eight participants (17%) complained about dazzle during blue light exposure and were removed from the analysis. Results from the 40 remaining participants (mean age +/- SD: 32.9+/-11.1) showed that countermeasures reduced the number of inappropriate line crossings (ILC) (F(2,91.11) = 6.64; p<0.05). Indeed, ILC were lower with coffee (12.51 [95% CI, 5.86 to 19.66], p = 0.001) and blue light (14.58 [CI, 8.75 to 22.58], p = 0.003) than with placebo (26.42 [CI, 19.90 to 33.71]). Similar results were found for SDLP. Treatments did not modify the quality, quantity and timing of 3 subsequent nocturnal sleep episodes. Despite a lesser tolerance, a non-inferior efficacy of continuous nocturnal blue light exposure compared with caffeine suggests that this in-car countermeasure, used occasionally, could be used to fight nocturnal sleepiness at the wheel in blue light-tolerant drivers, whatever their age. More studies are needed to determine the reproducibility of data and to verify if it can be generalized to women. Trial registration: ClinicalTrials.gov NCT01070004.
Address University of Bordeaux, Sommeil, Attention et Neuropsychiatrie, USR 3413, Bordeaux, France. jack.taillard@gmail.com
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ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:23094031; PMCID:PMC3477137 Approved no
Call Number IDA @ john @ Serial 347
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Author Kessel, L.; Siganos, G.; Jorgensen, T.; Larsen, M.
Title Sleep disturbances are related to decreased transmission of blue light to the retina caused by lens yellowing Type Journal Article
Year 2011 Publication Sleep Abbreviated Journal Sleep
Volume 34 Issue 9 Pages 1215-1219
Keywords (up) Adult; Age Factors; Aging/*pathology/physiology; Circadian Rhythm/physiology; Cross-Sectional Studies; Female; Fluorometry; Humans; Lens, Crystalline/*pathology/physiopathology; *Light; Male; Middle Aged; Retina/*physiopathology; Risk Factors; *Scattering, Radiation; Sleep Disorders/*etiology; Circadian rhythm; cataract; melanopsin; sleep; blue light
Abstract STUDY OBJECTIVES: Sleep pattern and circadian rhythms are regulated via the retinohypothalamic tract in response to stimulation of a subset of retinal ganglion cells, predominantly by blue light (450-490 nm). With age, the transmission of blue light to the retina is reduced because of the aging process of the human lens, and this may impair the photoentrainment of circadian rhythm leading to sleep disorders. The aim of the study was to examine the association between lens aging and sleep disorders. DESIGN: Cross-sectional population based study. SETTING: The study was performed at the Research Center for Prevention and Health, Glostrup Hospital, Denmark and at the Department of Ophthalmology, Herlev Hospital, Denmark. PARTICIPANTS: An age- and sex-stratified sample of 970 persons aged 30 to 60 years of age drawn from a sample randomly selected from the background population. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Sleep disturbances were evaluated by a combination of questionnaire and the use of prescription sleeping medication. Lens aging (transmission and yellowing) was measured objectively by lens autofluorometry. The risk of sleep disturbances was significantly increased when the transmission of blue light to the retina was low, even after correction for the effect of age and other confounding factors such as smoking habits, diabetes mellitus, gender, and the risk of ischemic heart disease (P < 0.0001). CONCLUSIONS: Filtration of blue light by the aging lens was significantly associated with an increased risk of sleep disturbances. We propose that this is a result of disturbance of photoentrainment of circadian rhythms.
Address Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Denmark. line.kessel@dadlnet.dk
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Series Volume Series Issue Edition
ISSN 0161-8105 ISBN Medium
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Notes PMID:21886359; PMCID:PMC3157663 Approved no
Call Number IDA @ john @ Serial 344
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Author Parent, M.-E.; El-Zein, M.; Rousseau, M.-C.; Pintos, J.; Siemiatycki, J.
Title Night work and the risk of cancer among men Type Journal Article
Year 2012 Publication American Journal of Epidemiology Abbreviated Journal Am J Epidemiol
Volume 176 Issue 9 Pages 751-759
Keywords (up) Adult; Aged; *Circadian Rhythm; Humans; Male; *Men's Health; Middle Aged; Neoplasms/*epidemiology; Occupations/*statistics & numerical data; Personnel Staffing and Scheduling/*statistics & numerical data; Quebec/epidemiology; Risk Factors; oncogenesis
Abstract Night work might influence cancer risk, possibly via suppression of melatonin release. In a population-based case-control study conducted in Montreal, Quebec, Canada, between 1979 and 1985, job histories, including work hours, were elicited from 3,137 males with incident cancer at one of 11 anatomic sites and from 512 controls. Compared with men who never worked at night, the adjusted odds ratios among men who ever worked at night were 1.76 (95% confidence interval (CI): 1.25, 2.47) for lung cancer, 2.03 (95% CI: 1.43, 2.89) for colon cancer, 1.74 (95% CI: 1.22, 2.49) for bladder cancer, 2.77 (95% CI: 1.96, 3.92) for prostate cancer, 2.09 (95% CI: 1.40, 3.14) for rectal cancer, 2.27 (95% CI: 1.24, 4.15) for pancreatic cancer, and 2.31 (95% CI: 1.48, 3.61) for non-Hodgkin's lymphoma. Equivocal evidence or no evidence was observed for cancers of the stomach (odds ratio (OR) = 1.34, 95% CI: 0.85, 2.10), kidney (OR = 1.42, 95% CI: 0.86, 2.35), and esophagus (OR = 1.51, 95% CI: 0.80, 2.84) and for melanoma (OR = 1.04, 95% CI: 0.49, 2.22). There was no evidence of increasing risk with increasing duration of night work, with risks generally being increased across all duration categories. Results suggest that night work may increase cancer risk at several sites among men.
Address INRS-Institut Armand-Frappier, University of Quebec, Laval, Canada. marie-elise.parent@iaf.inrs.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 0002-9262 ISBN Medium
Area Expedition Conference
Notes PMID:23035019 Approved no
Call Number IDA @ john @ Serial 158
Permanent link to this record