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Author Martinez-Nicolas, A.; Ortiz-Tudela, E.; Madrid, J.A.; Rol, M.A. url  doi
openurl 
  Title Crosstalk between environmental light and internal time in humans Type Journal Article
  Year 2011 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 28 Issue 7 Pages 617-629  
  Keywords 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  
  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 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21793693 Approved no  
  Call Number IDA @ john @ Serial 302  
Permanent link to this record
 

 
Author Boivin, D.B.; Boudreau, P.; Tremblay, G.M. url  doi
openurl 
  Title Phototherapy and orange-tinted goggles for night-shift adaptation of police officers on patrol Type Journal Article
  Year 2012 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 29 Issue 5 Pages 629-640  
  Keywords Human Health; Adaptation, Physiological/*physiology; Adult; Attention/physiology; Circadian Rhythm/physiology; Color; Darkness; *Eye Protective Devices/adverse effects; Female; Humans; Light; Male; Melatonin/analogs & derivatives/metabolism/urine; Phototherapy/*adverse effects; *Police; Psychomotor Performance/*physiology; Saliva/chemistry; Sleep/physiology; Work Schedule Tolerance/*physiology  
  Abstract The aim of the present combined field and laboratory study was to assess circadian entrainment in two groups of police officers working seven consecutive 8/8.5-h night shifts as part of a rotating schedule. Eight full-time police officers on patrol (mean age +/- SD: 29.8 +/- 6.5 yrs) were provided an intervention consisting of intermittent exposure to wide-spectrum bright light at night, orange-tinted goggles at sunrise, and maintenance of a regular sleep/darkness episode in the day. Orange-tinted goggles have been shown to block the melatonin-suppressing effect of light significantly more than neutral gray density goggles. Nine control group police officers (mean age +/- SD: 30.3 +/- 4.1 yrs) working the same schedule were enrolled. Police officers were studied before, after (in the laboratory), and during (ambulatory) a series of seven consecutive nights. Urine samples were collected at wake time and bedtime throughout the week of night work and during laboratory visits (1 x /3 h) preceding and following the work week to measure urinary 6-sulfatoxymelatonin (UaMT6s) excretion rate. Subjective alertness was assessed at the start, middle, and end of night shifts. A 10-min psychomotor vigilance task was performed at the start and end of each shift. Both laboratory visits consisted of two 8-h sleep episodes based on the prior schedule. Saliva samples were collected 2 x /h during waking episodes to assay their melatonin content. Subjective alertness (3 x /h) and performance (1 x /2 h) were assessed during wake periods in the laboratory. A mixed linear model was used to analyze the progression of UaMt6s excreted during daytime sleep episodes at home, as well as psychomotor performance and subjective alertness during night shifts. Two-way analysis of variance (ANOVA) (factors: laboratory visit and group) were used to compare peak salivary melatonin and UaMT6s excretion rate in the laboratory. In both groups of police officers, the excretion rate of UaMT6s at home was higher during daytime sleep episodes at the end compared to the start of the work week (p < .001). This rate increased significantly more in the intervention than control group (p = .032). A significant phase delay of salivary melatonin was observed in both groups at the end of study (p = .009), although no significant between-group difference was reached. Reaction speed dropped, and subjective alertness decreased throughout the night shift in both groups (p < .001). Reaction speed decreased throughout the work week in the control group (p </= .021), whereas no difference was observed in the intervention group. Median reaction time was increased as of the 5th and 6th nights compared to the 2nd night in controls (p </= .003), whereas it remained stable in the intervention group. These observations indicate better physiological adaptation in the intervention group compared to the controls.  
  Address Centre for Study and Treatment of Circadian Rhythms , Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Quebec, Canada. diane.boivin@douglas.mcgill.ca  
  Corporate Author Thesis  
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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:22621360 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 509  
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Author Vollmer, C.; Randler, C.; Di Milia, L. url  doi
openurl 
  Title Further evidence for the influence of photoperiod at birth on chronotype in a sample of German adolescents Type Journal Article
  Year 2012 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 29 Issue 10 Pages 1345-1351  
  Keywords Human Health; Adolescent; Child; Circadian Rhythm/*physiology; Female; Germany; Humans; Male; Parturition/*physiology; *Photoperiod; Puberty/physiology; *Seasons; Sleep/*physiology  
  Abstract Individuals differ in their circadian preferences (chronotype). There is evidence in the literature to support a season-of-birth effect on chronotype but the evidence is not convincing. In part, the relationship is obscured by a number of methodological differences between studies, including the measures used to define morningness, the way in which the seasons were categorized, and the sample size. This study adds to the literature in several ways. First, we adopt a new approach to categorizing the photoperiod rather than the calendar season; thus we prefer to use the term photoperiod at birth. Second, we used two measures of morningness. Third, we used a large and homogeneous German sample. The results show that adolescents (n = 2905) born during the increasing photoperiod (Feb-Apr) had a significantly later midpoint of sleep (MSFsc) than those born during the decreasing photoperiod (Aug-Oct). A similar pattern was found for the Composite Scale of Morningness (CSM). Furthermore, both measures of chronotype demonstrated a significant quadratic function over a 1-yr cycle. When looking at each of six consecutive years separately, the Composite Scale of Morningness suggests a cosine rhythm linked to increasing and decreasing photoperiods that becomes weaker in amplitude with increasing age. Despite the strengths in our study, the effect of photoperiod at birth on chronotype remains small. Future studies may require larger sample sizes, may need to explore how neonatal light exposure modulates chronotype, and may need to track how puberty and adolescent lifestyle habits mask the photoperiod effect.  
  Address Department of Biology, University of Education Heidelberg, Im Neuenheimer Feld 561-2, Heidelberg, Germany. vollmer@ph-heidelberg.de  
  Corporate Author Thesis  
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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:23130997 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 517  
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Author Kloog, I.; Haim, A.; Stevens, R.G.; Barchana, M.; Portnov, B.A. url  doi
openurl 
  Title Light at night co-distributes with incident breast but not lung cancer in the female population of Israel Type Journal Article
  Year 2008 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 25 Issue 1 Pages 65-81  
  Keywords Human Health; Breast Neoplasms/*epidemiology/etiology; Female; Humans; Israel/epidemiology; *Light; Lung Neoplasms/epidemiology; Multivariate Analysis; Risk Factors  
  Abstract Recent studies of shift-working women have reported that excessive exposure to light at night (LAN) may be a risk factor for breast cancer. However, no studies have yet attempted to examine the co-distribution of LAN and breast cancer incidence on a population level with the goal to assess the coherence of these earlier findings with population trends. Coherence is one of Hill's “criteria” (actually, viewpoints) for an inference of causality. Nighttime satellite images were used to estimate LAN levels in 147 communities in Israel. Multiple regression analysis was performed to investigate the association between LAN and breast cancer incidence rates and, as a test of the specificity of our method, lung cancer incidence rates in women across localities under the prediction of a link with breast cancer but not lung cancer. After adjusting for several variables available on a population level, such as ethnic makeup, birth rate, population density, and local income level, a strong positive association between LAN intensity and breast cancer rate was revealed (p<0.05), and this association strengthened (p<0.01) when only statistically significant factors were filtered out by stepwise regression analysis. Concurrently, no association was found between LAN intensity and lung cancer rate. These results provide coherence of the previously reported case-control and cohort studies with the co-distribution of LAN and breast cancer on a population basis. The analysis yielded an estimated 73% higher breast cancer incidence in the highest LAN exposed communities compared to the lowest LAN exposed communities.  
  Address Department of Natural Resources & Environmental Management, University of Haifa, Haifa, Israel  
  Corporate Author Thesis  
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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:18293150 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 528  
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Author Kloog, I.; Portnov, B.A.; Rennert, H.S.; Haim, A. url  doi
openurl 
  Title Does the modern urbanized sleeping habitat pose a breast cancer risk? Type Journal Article
  Year 2011 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 28 Issue 1 Pages 76-80  
  Keywords Human Health; ged; Alcohol Drinking/adverse effects; Breast Neoplasms/*etiology; Case-Control Studies; Circadian Rhythm/*radiation effects; Female; Humans; Light/*adverse effects; Middle Aged; Odds Ratio; Risk Factors; *Sleep; Urbanization  
  Abstract Due to its disruptive effects on circadian rhythms and sleep deprivation at night, shiftworking is currently recognized as a risk factor for breast cancer (BC). As revealed by the present analysis based on a comparative case-control study of 1679 women, exposure to light-at-night (LAN) in the “sleeping habitat” is significantly associated with BC risk (odds ratio [OR] = 1.220, 95% confidence interval [CI] = 1.118-1.311; p < .001), controlling for education, ethnicity, fertility, and alcohol consumption. The novelty of the present research is that, to the best of the authors' knowledge, it is the first study to have identified an unequivocal positive association between bedroom-light intensity and BC risk. Thus, according to the results of the present study, not only should artificial light exposure in the working environment be considered as a potential risk factor for BC, but also LAN in the “sleeping habitat.”  
  Address Department of Natural Resources and Environmental Management, Graduate School of Management, University of Haifa, 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 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21182407 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 770  
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