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Author Kloog, I.; Haim, A.; Stevens, R.G.; Portnov, B.A.
Title Global co-distribution of light at night (LAN) and cancers of prostate, colon, and lung in men Type Journal Article
Year 2009 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 26 Issue 1 Pages 108-125
Keywords Circadian Rhythm; Colonic Neoplasms/*epidemiology; Electricity; Humans; Incidence; *Light; Lung Neoplasms/*epidemiology; Male; Prostatic Neoplasms/*epidemiology; Risk Factors; Urban Population; World Health; Oncogenesis
Abstract The incidence rates of cancers in men differ by countries of the world. We compared the incidence rates of three of the most common cancers (prostate, lung, and colon) in men residing in 164 different countries with the population-weighted light at night (LAN) exposure and with several developmental and environmental indicators, including per capita income, percent urban population, and electricity consumption. The estimate of per capita LAN exposure was a novel aspect of this study. Both ordinary least squares (OLS) and spatial error (SE) regression models were used in the analysis. We found a significant positive association between population exposure to LAN and incidence rates of prostate cancer, but no such association with lung cancer or colon cancer. The prostate cancer result is consistent with a biological theory and a limited number of previous studies of circadian disruption and risk. The LAN-prostate cancer connection is postulated to be due to suppression of melatonin and/or disruption of clock gene function. An analysis holding other variables at average values across the 164 countries yielded a risk of prostate cancer in the highest LAN-exposed countries 110% higher than in the lowest LAN exposed countries. This observed association is a necessary condition for a potentially large effect of LAN on risk of prostate cancer. However, it is not sufficient due to potential confounding by factors that increase the risk of prostate cancer and are also associated with LAN among the studied countries.
Address Department of Natural Resources & Environmental Management, Faculty of Social Sciences, University of Haifa, Haifa, Israel
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Language English Summary Language Original Title
Series Editor (down) Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:19142761 Approved no
Call Number IDA @ john @ Serial 163
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Author Davis, S.; Mirick, D.K.; Stevens, R.G.
Title Night Shift Work, Light at Night, and Risk of Breast Cancer Type Journal Article
Year 2001 Publication JNCI Journal of the National Cancer Institute Abbreviated Journal JNCI Journal of the National Cancer Institute
Volume 93 Issue 20 Pages 1557-1562
Keywords light at night; oncogenesis; melatonin; shiftwork; breast cancer; *Cancer
Abstract Exposure to light at night may increase the risk of breast cancer by suppressing the normal nocturnal production of melatonin by the pineal gland, which, in turn, could increase the release of estrogen by the ovaries. This study investigated whether such exposure is associated with an increased risk of breast cancer in women. Methods: Case patients (n = 813), aged 20–74 years, were diagnosed from November 1992 through March 1995; control subjects (n = 793) were identified by random-digit dialing and were frequency matched according to 5-year age groups. An in-person interview was used to gather information on sleep habits and bedroom lighting environment in the 10 years before diagnosis and lifetime occupational history. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of conditional logistic regression, with adjustment for other potential risk factors. Results: Breast cancer risk was increased among subjects who frequently did not sleep during the period of the night when melatonin levels are typically at their highest (OR = 1.14 for each night per week; 95% CI = 1.01 to 1.28). Risk did not increase with interrupted sleep accompanied by turning on a light. There was an indication of increased risk among subjects with the brightest bedrooms. Graveyard shiftwork was associated with increased breast cancer risk (OR = 1.6; 95% CI = 1.0 to 2.5), with a trend of increased risk with increasing years and with more hours per week of graveyard shiftwork (P = .02, Wald chi-squared test). Conclusion: The results of this study provide evidence that indicators of exposure to light at night may be associated with the risk of developing breast cancer.
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Series Volume Series Issue Edition
ISSN 0027-8874 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 164
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Author Obayashi, K.; Saeki, K.; Iwamoto, J.; Ikada, Y.; Kurumatani, N.
Title Exposure to light at night and risk of depression in the elderly Type Journal Article
Year 2013 Publication Journal of Affective Disorders Abbreviated Journal J Affect Disord
Volume 151 Issue 1 Pages 331-336
Keywords Aged; Circadian Rhythm; Cross-Sectional Studies; Depression/*etiology; Female; Humans; Light/*adverse effects; Male; Melatonin/urine; Psychiatric Status Rating Scales; Risk Factors; Circadian rhythm; Daytime light; Depression; Elderly; Light at night; Melatonin; Mental Health
Abstract BACKGROUND: Recent advances in understanding the fundamental links between chronobiology and depressive disorders have enabled exploring novel risk factors for depression in the field of biological rhythms. Increased exposure to light at night (LAN) is common in modern life, and LAN exposure is associated with circadian misalignment. However, whether LAN exposure in home settings is associated with depression remains unclear. METHODS: We measured the intensities of nighttime bedroom light and ambulatory daytime light along with overnight urinary melatonin excretion (UME) in 516 elderly individuals (mean age, 72.8). Depressive symptoms were assessed using the Geriatric Depression Scale. RESULTS: The median nighttime light intensity was 0.8lx (interquartile range, 0.2-3.3). The depressed group (n=101) revealed significantly higher prevalence of LAN exposure (average intensity, >/= 5 lx) compared with that of the nondepressed group (n=415) using a multivariate logistic regression model adjusted for daytime light exposure, insomnia, hypertension, sleep duration, and physical activity [adjusted odds ratio (OR): 1.89; 95% confidence interval (CI), 1.10-3.25; P=0.02]. Consistently, another parameter of LAN exposure (duration of intensity >/= 10 lx, >/= 30 min) was significantly more prevalent in the depressed than in the nondepressed group (adjusted OR: 1.71; 95% CI, 1.01-2.89; P=0.046). In contrast, UME was not significantly associated with depressive symptoms. LIMITATION: Cross-sectional analysis. CONCLUSION: These results suggested that LAN exposure in home settings is significantly associated with depressive symptoms in the general elderly population. The risk of depression may be reduced by keeping nighttime bedroom dark.
Address Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara, Japan. obayashi@naramed-u.ac.jp
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0165-0327 ISBN Medium
Area Expedition Conference
Notes PMID:23856285 Approved no
Call Number IDA @ john @ Serial 165
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Author McFadden, E.; Jones, M.E.; Schoemaker, M.J.; Ashworth, A.; Swerdlow, A.J.
Title The Relationship Between Obesity and Exposure to Light at Night: Cross-Sectional Analyses of Over 100,000 Women in the Breakthrough Generations Study Type Journal Article
Year 2014 Publication American Journal of Epidemiology Abbreviated Journal Am J Epidemiol
Volume 180 Issue 3 Pages 245-250
Keywords body mass index; circadian rhythm; light at night; obesity; sleep; sleeping habits
Abstract There has been a worldwide epidemic of obesity in recent decades. In animal studies, there is convincing evidence that light exposure causes weight gain, even when calorie intake and physical activity are held constant. Disruption of sleep and circadian rhythms by exposure to light at night (LAN) might be one mechanism contributing to the rise in obesity, but it has not been well-investigated in humans. Using multinomial logistic regression, we examined the association between exposure to LAN and obesity in questionnaire data from over 100,000 women in the Breakthrough Generations Study, a cohort study of women aged 16 years or older who were living in the United Kingdom and recruited during 2003-2012. The odds of obesity, measured using body mass index, waist:hip ratio, waist:height ratio, and waist circumference, increased with increasing levels of LAN exposure (P < 0.001), even after adjustment for potential confounders such as sleep duration, alcohol intake, physical activity, and current smoking. We found a significant association between LAN exposure and obesity which was not explained by potential confounders we could measure. While the possibility of residual confounding cannot be excluded, the pattern is intriguing, accords with the results of animal experiments, and warrants further investigation.
Address
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Language English Summary Language Original Title
Series Editor (down) Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-9262 ISBN Medium
Area Expedition Conference
Notes PMID:24875371 Approved no
Call Number IDA @ john @ Serial 166
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Author Fonken, L.K.; Weil, Z.M.; Nelson, R.J.
Title Dark nights reverse metabolic disruption caused by dim light at night Type Journal Article
Year 2013 Publication Obesity (Silver Spring, Md.) Abbreviated Journal Obesity (Silver Spring)
Volume 21 Issue 6 Pages 1159-1164
Keywords Animals; Body Mass Index; Energy Intake; Gene Expression; Glucose Tolerance Test; *Light; Male; Mice; Obesity/*epidemiology/etiology; *Photoperiod; Weight Gain
Abstract OBJECTIVE: The increasing prevalence of obesity and related metabolic disorders coincides with increasing exposure to light at night. Previous studies report that mice exposed to dim light at night (dLAN) develop symptoms of metabolic syndrome. This study investigated whether mice returned to dark nights after dLAN exposure recover metabolic function. DESIGN AND METHODS: Male Swiss-Webster mice were assigned to either: standard light-dark (LD) conditions for 8 weeks (LD/LD), dLAN for 8 weeks (dLAN/dLAN), LD for 4 weeks followed by 4 weeks of dLAN (LD/dLAN), and dLAN for 4 weeks followed by 4 weeks of LD (dLAN/LD). RESULTS: After 4 weeks in their respective lighting conditions both groups initially placed in dLAN increased body mass gain compared to LD mice. Half of the dLAN mice (dLAN/LD) were then transferred to LD and vice versa (LD/dLAN). Following the transfer dLAN/dLAN and LD/dLAN mice gained more weight than LD/LD and dLAN/LD mice. At the conclusion of the study dLAN/LD mice did not differ from LD/LD mice with respect to weight gain and had lower fat pad mass compared to dLAN/dLAN mice. Compared to all other groups dLAN/dLAN mice decreased glucose tolerance as indicated by an intraperitoneal glucose tolerance test at week 7, indicating that dLAN/LD mice recovered glucose metabolism. dLAN/dLAN mice also increased MAC1 mRNA expression in peripheral fat as compared to both LD/LD and dLAN/LD mice, suggesting peripheral inflammation is induced by dLAN, but not sustained after return to LD. CONCLUSION: These results suggest that re-exposure to dark nights ameliorates metabolic disruption caused by dLAN exposure.
Address Department of Neuroscience and Institute for Behavioral Medicine Research, Wexner Medical Center, Ohio State University, Columbus, Ohio 43210, USA. fonken.1@osu.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor (down) Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1930-7381 ISBN Medium
Area Expedition Conference
Notes PMID:23666854 Approved no
Call Number IDA @ john @ Serial 167
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