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Author Li, Q.; Zheng, T.; Holford, T.R.; Boyle, P.; Zhang, Y.; Dai, M.
Title Light at night and breast cancer risk: results from a population-based case-control study in Connecticut, USA Type Journal Article
Year 2010 Publication Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 21 Issue 12 Pages 2281-2285
Keywords (up) Adult; Aged; Aged, 80 and over; Breast Neoplasms/epidemiology/*etiology; Carcinoma/epidemiology/*etiology; Case-Control Studies; Circadian Rhythm/physiology; Connecticut/epidemiology; Female; Humans; *Light/adverse effects; Middle Aged; Population; Questionnaires; Risk Factors; United States/epidemiology; Work Schedule Tolerance/physiology; Oncogenesis
Abstract OBJECTIVE: To investigate the potential association between domestic exposure to light at night (LAN) and the risk of human breast cancer. METHODS: A case-control study of female breast cancer was conducted in Connecticut. A total of 363 incident breast cancer cases and 356 age frequency-matched controls were interviewed using a standardized, structured questionnaire to obtain information on sleeping patterns and bedroom light environment. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional multivariate logistic regression. RESULTS: A non-significantly increased risk of breast cancer was observed among postmenopausal women for those keeping lights on while sleeping (OR = 1.4, 95% CI 0.7, 2.7), those who reported mainly sleeping in the daytime (OR = 1.4, 95% CI 0.5, 4.3), and those not drawing the curtains/window shades while sleeping at night (OR = 1.2, 95% CI 0.8, 1.9). CONCLUSION: The results from this study suggest a potential increased risk of breast cancer associated with domestic exposure to LAN. Further studies with larger sample size are needed to confirm the results.
Address Department of Social Medicine, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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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:20927578; PMCID:PMC3154700 Approved no
Call Number IDA @ john @ Serial 161
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Author Knutsson, A.; Alfredsson, L.; Karlsson, B.; Akerstedt, T.; Fransson, E.I.; Westerholm, P.; Westerlund, H.
Title Breast cancer among shift workers: results of the WOLF longitudinal cohort study Type Journal Article
Year 2013 Publication Scandinavian Journal of Work, Environment & Health Abbreviated Journal Scand J Work Environ Health
Volume 39 Issue 2 Pages 170-177
Keywords (up) Adult; Aged; Breast Neoplasms/*epidemiology/etiology; Circadian Rhythm; Female; Humans; Incidence; Longitudinal Studies; Middle Aged; Proportional Hazards Models; Risk Assessment; Sweden/epidemiology; *Work Schedule Tolerance; oncogenesis
Abstract OBJECTIVE: The aim of this study was to investigate whether shift work (with or without night work) is associated with increased risk of breast cancer. METHODS: The population consisted of 4036 women. Data were obtained from WOLF (Work, Lipids, and Fibrinogen), a longitudinal cohort study. Information about baseline characteristics was based on questionnaire responses and medical examination. Cancer incidence from baseline to follow-up was obtained from the national cancer registry. Two exposure groups were identified: shift work with and without night work. The group with day work only was used as the reference group in the analysis. Cox regression analysis was used to calculate relative risk. RESULTS: In total, 94 women developed breast cancer during follow-up. The average follow-up time was 12.4 years. The hazard ratio for breast cancer was 1.23 [95% confidence interval (95% CI) 0.70-2.17] for shifts without night work and 2.02 (95% CI 1.03-3.95) for shifts with night work. When including only women <60 years of age, the risk estimates were 1.18 (95% CI 0.67-2.07) for shifts without night work, and 2.15 (95% CI 1.10-4.21) for shifts with night work. CONCLUSIONS: Our results indicate an increased risk for breast cancer among women who work shifts that includes night work.
Address Department of Health Sciences, Mid Sweden University, Sundsvall. Sweden. Anders.Knutsson@miun.se
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0355-3140 ISBN Medium
Area Expedition Conference
Notes PMID:23007867 Approved no
Call Number IDA @ john @ Serial 154
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Author Cajochen, C.; Altanay-Ekici, S.; Munch, M.; Frey, S.; Knoblauch, V.; Wirz-Justice, A.
Title Evidence that the lunar cycle influences human sleep Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 15 Pages 1485-1488
Keywords (up) Adult; Aged; Cross-Sectional Studies; Electroencephalography; Female; Humans; Hydrocortisone/analysis/metabolism; Male; Melatonin/analysis/metabolism; Middle Aged; Moon; Nontherapeutic Human Experimentation; Periodicity; Saliva/metabolism; Sleep/*physiology; Sleep Stages/physiology; Young Adult
Abstract Endogenous rhythms of circalunar periodicity ( approximately 29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species [1, 2]. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior [3]. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues.
Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4012 Basel, Switzerland. christian.cajochen@upkbs.ch
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23891110 Approved no
Call Number IDA @ john @ Serial 140
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Author Figueiro, M.G.; Bierman, A.; Plitnick, B.; Rea, M.S.
Title Preliminary evidence that both blue and red light can induce alertness at night Type Journal Article
Year 2009 Publication BMC Neuroscience Abbreviated Journal BMC Neurosci
Volume 10 Issue Pages 105
Keywords (up) Adult; Alpha Rhythm; Analysis of Variance; Beta Rhythm; Circadian Rhythm/*physiology; Cornea/physiology; Dose-Response Relationship, Radiation; Electrocardiography; Female; Humans; *Light; Male; Melatonin/secretion; Middle Aged; *Photic Stimulation; Psychomotor Performance; Radioimmunoassay; Salivary Glands/secretion; Wakefulness/*physiology; physiology of vision; blue light; red light
Abstract BACKGROUND: A variety of studies have demonstrated that retinal light exposure can increase alertness at night. It is now well accepted that the circadian system is maximally sensitive to short-wavelength (blue) light and is quite insensitive to long-wavelength (red) light. Retinal exposures to blue light at night have been recently shown to impact alertness, implicating participation by the circadian system. The present experiment was conducted to look at the impact of both blue and red light at two different levels on nocturnal alertness. Visually effective but moderate levels of red light are ineffective for stimulating the circadian system. If it were shown that a moderate level of red light impacts alertness, it would have had to occur via a pathway other than through the circadian system. METHODS: Fourteen subjects participated in a within-subject two-night study, where each participant was exposed to four experimental lighting conditions. Each night each subject was presented a high (40 lx at the cornea) and a low (10 lx at the cornea) diffuse light exposure condition of the same spectrum (blue, lambda(max) = 470 nm, or red, lambda(max) = 630 nm). The presentation order of the light levels was counterbalanced across sessions for a given subject; light spectra were counterbalanced across subjects within sessions. Prior to each lighting condition, subjects remained in the dark (< 1 lx at the cornea) for 60 minutes. Electroencephalogram (EEG) measurements, electrocardiogram (ECG), psychomotor vigilance tests (PVT), self-reports of sleepiness, and saliva samples for melatonin assays were collected at the end of each dark and light periods. RESULTS: Exposures to red and to blue light resulted in increased beta and reduced alpha power relative to preceding dark conditions. Exposures to high, but not low, levels of red and of blue light significantly increased heart rate relative to the dark condition. Performance and sleepiness ratings were not strongly affected by the lighting conditions. Only the higher level of blue light resulted in a reduction in melatonin levels relative to the other lighting conditions. CONCLUSION: These results support previous findings that alertness may be mediated by the circadian system, but it does not seem to be the only light-sensitive pathway that can affect alertness at night.
Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA. figuem@rpi.edu
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 1471-2202 ISBN Medium
Area Expedition Conference
Notes PMID:19712442; PMCID:PMC2744917 Approved no
Call Number IDA @ john @ Serial 285
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Author Peplonska, B.; Bukowska, A.; Sobala, W.; Reszka, E.; Gromadzinska, J.; Wasowicz, W.; Lie, J.A.; Kjuus, H.; Ursin, G.
Title Rotating night shift work and mammographic density Type Journal Article
Year 2012 Publication Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology Abbreviated Journal Cancer Epidemiol Biomarkers Prev
Volume 21 Issue 7 Pages 1028-1037
Keywords (up) Adult; Breast/*pathology; Breast Neoplasms/*etiology/*pathology; Circadian Rhythm/*physiology; Cross-Sectional Studies; Female; Humans; Melatonin/urine; Middle Aged; *Midwifery; *Nursing Staff; Questionnaires; Risk Factors; *Work Schedule Tolerance; oncogenesis
Abstract BACKGROUND: An increased risk of breast cancer has been observed in night shift workers. Exposure to artificial light at night and disruption of the endogenous circadian rhythm with suppression of the melatonin synthesis have been suggested mechanisms. We investigated the hypothesis that rotating night shift work is associated with mammographic density. METHODS: We conducted a cross-sectional study on the association between rotating night shift work characteristics, 6-sulfatoxymelatonin (MT6s) creatinine adjusted in a spot morning urine sample, and a computer-assisted measure of mammographic density in 640 nurses and midwives ages 40 to 60 years. The associations were evaluated using regression models adjusted for age, body mass index, menopausal status, age at menopause, age at menarche, smoking, and the calendar season of the year when mammography was conducted. RESULTS: The adjusted means of percentage of mammographic density and absolute density were slightly higher among women working rotating night shifts but not statistically significant [percentage of mammographic density = 23.6%, 95% confidence interval (CI), 21.9%-25.4% vs. 22.5%, 95% CI, 20.8%-24.3%; absolute density = 23.9 cm(2), 95% CI, 21.4-26.4 cm(2) vs. 21.8 cm(2), 95% CI, 19.4-24.3 cm(2) in rotating night shift and day shift nurses, respectively). There were no significant associations between the current or cumulative rotating night shift work exposure metrics and mammographic density. No association was observed between morning MT6s and mammographic density. CONCLUSIONS: The hypothesis on the link between rotating night shift work, melatonin synthesis disruption, and mammographic density is not supported by the results of the present study. IMPACT: It is unlikely that the development of breast cancer in nurses working rotating night shifts is mediated by an increase in mammographic density.
Address Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland. beatap@imp.lodz.pl
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 1055-9965 ISBN Medium
Area Expedition Conference
Notes PMID:22539602 Approved no
Call Number IDA @ john @ Serial 159
Permanent link to this record