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Lu J, Zou R, Yang Y, Bai X, Wei W, Ding R, Hua X. Association between nocturnal light exposure and melatonin in humans: a meta-analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:3425-3434. [PMID: 38123771 DOI: 10.1007/s11356-023-31502-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Night shift workers are more susceptible to circadian rhythm disturbances due to their prolonged exposure to nighttime light. This exposure during abnormal periods causes inappropriate suppression of melatonin synthesis and secretion in the pineal gland, thereby disrupting circadian rhythms. While it is believed that nocturnal light exposure is involved in suppressing melatonin secretion, research findings in this area have been inconsistent. METHODS Thirteen publications retrieved from PubMed and Web of Science databases were included to compare the differences between night shift workers and controls using aggregated mean differences (MD) and 95% confidence intervals (CI). RESULTS After a comprehensive review, 13 publications were included and data on urinary melatonin metabolite 6-sulfameoxymelatonin(aMT6s) were collected for meta-analysis. The results showed that the morning urinary aMT6s levels were significantly lower in the exposed group than in the non-exposed group (MD = -3.69, 95%CI = (-5.41, -1.98), P < 0.0001), with no significant heterogeneity among the original studies (I2 = 42%, P = 0.13). In addition, night shift workers had significantly lower mean levels of 24-h urinary aMT6s than day shift workers (MD = -3.38, 95%CI = (-4.27, -2.49), P < 0.00001, I2 = 0). Nocturnal light was correlated with nocturnal urine aMT6s secretion and inhibited nocturnal aMT6s secretion (MD = -11.68, 95%CI = (-15.70, -7.67), P < 0.00001, I2 = 0). Additionally, nocturnal light inhibited the secretion of melatonin in the blood, with no significant heterogeneity between studies (MD = -11.37, 95%CI = (-15.41, -7.33), P < 0.00001, I2 = 0). CONCLUSION The findings of this study indicate that exposure to nocturnal light among night shift workers leads to inhibition of melatonin secretion.
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Affiliation(s)
- Juan Lu
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Ronghao Zou
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Yuyao Yang
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Xiaoyue Bai
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Wei Wei
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Rui Ding
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China
| | - Xiaohui Hua
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, 230032, People's Republic of China.
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Colding-Jørgensen P, Hestehave S, Abelson KSP, Kalliokoski O. Hair glucocorticoids are not a historical marker of stress - Exploring the time-scale of corticosterone incorporation into hairs in a rat model. Gen Comp Endocrinol 2023; 341:114335. [PMID: 37302763 DOI: 10.1016/j.ygcen.2023.114335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/13/2023]
Abstract
Hair glucocorticoids are increasingly popular biomarkers, used across numerous research fields, and studied species, as a measure of stress. Although they are suggested to be a proxy of the average HPA axis activity spanning a period of weeks or months into the past, this theory has never been tested. In the present study, adrenalectomized rats with no endogenous (adrenal) glucocorticoid production were used to study how circulating glucocorticoid levels would be reflected in the glucocorticoid levels found in hair samples. By dosing the animals daily with high levels of corticosterone for seven days, while sampling hairs before, during, and after treatments, a timeline for glucocorticoid uptake into hairs was constructed. This kinetic profile was compared to two hypothetical models, and the theory that hair glucocorticoids are a record of historical stress had to be rejected. Corticosterone concentrations in hairs were found to increase within three hours of the first injection, the highest concentrations were found on the seventh day of treatments, and the decrease in concentrations post-treatment suggests rapid elimination. We speculate that hair glucocorticoid levels can only be used to characterize a stress-response for a few days following a postulated stressor. An updated model, where glucocorticoids diffuse into, along, and out of hairs needs to be adopted to reconcile the experimentally obtained data. The inescapable consequence of this updated model is that hair glucocorticoids become a marker of - and can only be used to study - recent, or ongoing, stress, as opposed to historical events, weeks or months in the past.
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Affiliation(s)
- Pernille Colding-Jørgensen
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Sara Hestehave
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Cell and Developmental Biology, University College London, United Kingdom
| | - Klas S P Abelson
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Otto Kalliokoski
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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The Effect of Shiftwork on Body Composition: A Comparative Cross-sectional Study Among Health Care Workers. J Occup Environ Med 2022; 64:e757-e762. [PMID: 36070547 DOI: 10.1097/jom.0000000000002692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE This study compared the body composition parameters between shiftworkers and nonshiftworkers in a hospital setting in Sri Lanka. METHODS A comparative cross-sectional study was carried out among a sample of 78 health care workers, recruited by a stratified random sampling technique. Subjects underwent anthropometric and bioimpedentiometric analysis for body composition parameters. RESULTS The mean (SD) body fat percentage (BF%) of shiftworking women (40.8 [SD, 6.8%]) was significantly higher than day-working women (36.7% [SD, 5.9%]) ( P < 0.05). Mean BF% between day and shift groups did not significantly differ (33.0% [SD, 6.9%] vs 32.4% [SD, 10.7%]). Body mass index and waist circumference were significantly higher among shiftworking women ( P < 0.05), whereas male workers showed the opposite trend. CONCLUSION Prolonged exposure to shiftwork was associated with a higher BF%. Therefore, interventions for shiftworkers must be addressed, focusing on improving body composition.
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Abstract
PURPOSE OF REVIEW Review recent literature investigating the relationship between bone health and sleep/circadian disruptions (e.g., abnormal sleep duration, night shift work). RECENT FINDINGS Short and long sleep are associated with low bone mineral density (BMD). Recent data from observational studies identified an increased risk of fracture in women with short sleep. Studies suggest that age, sex, weight change, and concurrent circadian misalignment may modify the effects of sleep restriction on bone metabolism. Interventional studies demonstrate alterations in bone metabolism and structure in response to circadian disruption that could underlie the increased fracture risk seen with night shift work. The effects of sleep and circadian disruption during adolescence may have lifelong skeletal consequences if they adversely impact bone modeling. Data suggest that short sleep and night shift work negatively impact bone metabolism and health. Rigorous studies of prevalent sleep and circadian disruptions are needed to determine mechanisms and develop prevention strategies to optimize lifelong skeletal health.
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Affiliation(s)
- Christine Swanson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave., Mail Stop 8106, Aurora, CO, 80045, USA.
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Braam W, Spruyt K. Reference intervals for 6-Sulfatoxymelatonin in urine: a meta-analysis. Sleep Med Rev 2022; 63:101614. [DOI: 10.1016/j.smrv.2022.101614] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/16/2022] [Accepted: 02/16/2022] [Indexed: 12/11/2022]
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Calderon-Jofre R, Moraga D, Moraga FA. The Effect of Chronic Intermittent Hypobaric Hypoxia on Sleep Quality and Melatonin Serum Levels in Chilean Miners. Front Physiol 2022; 12:809360. [PMID: 35222064 PMCID: PMC8864145 DOI: 10.3389/fphys.2021.809360] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
High-altitude mining is an important economic resource for Chile. These workers are exposed to chronic intermittent hypobaric hypoxia (CIHH), which reduces their sleep quality and increases the risk of accidents and long-term illnesses. Melatonin, a hormone produced by the pineal gland, is a sleep inducer that regulates the circadian cycle and may be altered in populations subjected to CIHH. This work aimed to assess the relationship between altitude, sleep quality, and plasma melatonin concentrations in miners with CIHH exposure. 288 volunteers were recruited from five altitudes (0, 1,600, 2,500, 3,500, and 4,500 m). All volunteers worked for 7 days at altitude, followed by 7 days of rest at sea level. We performed anthropometric assessments, nocturnal oximetry, sleep quality and sleepiness surveys, and serum melatonin levels upon awakening. Although oxygen saturation progressively decreased and heart rate increased at higher altitudes, subjective perception of sleep quality was not significantly different, and sleepiness increased in all groups compared to population at sea level. Similarly, melatonin levels increased at all assessed altitudes compared to the population at sea level. These data confirm that sleep disturbances associated with CIHH increase morning melatonin levels. Therefore, this hormone and could potentially serve as a biomarker of sleep quality.
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Affiliation(s)
- Rodrigo Calderon-Jofre
- Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Daniel Moraga
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universidad de Tarapacá, Arica, Chile
| | - Fernando A. Moraga
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universidad de Tarapacá, Arica, Chile
- *Correspondence: Fernando A. Moraga,
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Evaluation of multiple reaction monitoring cubed performed by a quadrupole-linear ion trap mass spectrometer for quantitative determination of 6-sulfatoxymelatonin in urine. J Chromatogr B Analyt Technol Biomed Life Sci 2022; 1190:123094. [PMID: 35030474 DOI: 10.1016/j.jchromb.2021.123094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 11/29/2021] [Accepted: 12/28/2021] [Indexed: 01/30/2023]
Abstract
Liquid chromatography (LC) - mass spectrometry quantitative analysis of substances in biological samples is usually performed in the multiple reaction monitoring (MRM) variant. In complex biological matrices, strong interferences can be observed when using the LC-MRM method. Interference levels can be significantly reduced by using LC - multiple reaction monitoring cubed (MRM3). 6-sulfatoxymelatonin (6-SM) is a metabolite of melatonin, an important regulator of many biological processes. The quantitative analysis of 6-SM in urine allows monitoring of the melatonin level in the blood. The aim of the present work was to evaluate the LC-MRM3 method for the quantitative determination of 6-SM in urine. We found that for 6-SM in aqueous solutions, under some parameters of the MRM3 experiment, the effect of degradation of the MRM3 signal is observed. When analyzing 6-SM in urine, this signal degradation effect was significantly reduced. We have shown that optimization of such parameters of the MRM3 method as the linear ion trap fill time, the number of scans to sum, and the range of triple-stage scan allows obtaining the LC-MRM3 method, which is comparable to the LC-MRM in sensitivity and significantly exceeds it in selectivity.
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Deng S, Wang Q, Fan J, Yang X, Mei J, Lu J, Chen G, Yang Y, Liu W, Wang R, Han Y, Sheng R, Wang W, Ba L, Ding F. Correlation of Circadian Rhythms of Heart Rate Variability Indices with Stress, Mood, and Sleep Status in Female Medical Workers with Night Shifts. Nat Sci Sleep 2022; 14:1769-1781. [PMID: 36225321 PMCID: PMC9549795 DOI: 10.2147/nss.s377762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
PURPOSE Heart rate variability (HRV) indices have been used as stress indicators. Rare studies investigated the associations of circadian rhythms of the HRV indices with the stress, mood, and sleep conditions in populations under stress. METHODS In total 257 female participants (203 shift workers and 54 non-shift workers) were included. All the participants completed a structured questionnaire to assess the stress, mood, and sleep conditions and performed 24-hour Holter electrocardiogram monitoring on the day away from shifts. Using epochs of 1-min or 5-min beat-to-beat intervals, the HRV indices (SDNN, RMSSD, LF, HF, LF/HF, and LFnu, SD1, SD2, SD1/SD2) were plotted as a function of time and fitted into cosine periodic curves, respectively. Three mathematical parameters based on the cosine periodic curves were extracted, MESOR (M, overall averages of the cosine curve), amplitude (A, amplitude of the peak of the cosine curve), and acrophase (θ, latency to the peak) to quantify the circadian rhythms of the HRV indices. Multivariable linear regression models were used to reveal the associations of these parameters with the clinical assessments of stress, mood, or sleep conditions, as well as with the 24-h averages of the HRV indices. RESULTS The parameters M and A of SDNN, RMSSD, LF, and HF, and θ of LF/HF and LFnu significantly differ between shift and non-shift workers. The parameter θ of LF/HF positively correlates with the severity of stress and anxiety. The parameter A of LF/HF and LFnu also positively correlates with daytime sleepiness and sleep fragmentation. In addition, the parameters M and A instead of θ of SDNN, RMSSD, LF, LF/HF, and LFnu significantly correlate with the 24-h averages of HRV indices. CONCLUSION The circadian rhythms of the HRV indices over 24 hours can, to some extent, predict the severity of stress, emotion and sleep conditions in female populations under stress.
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Affiliation(s)
- Saiyue Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Quan Wang
- School of Nursing, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, People's Republic of China
| | - Jingjing Fan
- Cardiac Unit, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Xiaoyun Yang
- Cardiac Unit, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Junhua Mei
- Department of Neurology, Wuhan No.1 Hospital, Wuhan, 430022, People's Republic of China
| | - Jiajia Lu
- Cardiac Unit, Wuhan No.1 Hospital, Wuhan, 430022, People's Republic of China
| | - Guohua Chen
- Department of Neurology, Wuhan No.1 Hospital, Wuhan, 430022, People's Republic of China
| | - Yuan Yang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Wenhua Liu
- Department of Clinical Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, People's Republic of China
| | - Runsen Wang
- Huawei Technologies Co, Shenzhen, People's Republic of China
| | - Yujia Han
- Huawei Technologies Co, Shenzhen, People's Republic of China
| | - Rong Sheng
- Huawei Technologies Co, Shenzhen, People's Republic of China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Li Ba
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Fengfei Ding
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.,Department of Pharmacology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
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Boivin DB, Boudreau P, Kosmadopoulos A. Disturbance of the Circadian System in Shift Work and Its Health Impact. J Biol Rhythms 2021; 37:3-28. [PMID: 34969316 PMCID: PMC8832572 DOI: 10.1177/07487304211064218] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The various non-standard schedules required of shift workers force abrupt changes in the timing of sleep and light-dark exposure. These changes result in disturbances of the endogenous circadian system and its misalignment with the environment. Simulated night-shift experiments and field-based studies with shift workers both indicate that the circadian system is resistant to adaptation from a day- to a night-oriented schedule, as determined by a lack of substantial phase shifts over multiple days in centrally controlled rhythms, such as those of melatonin and cortisol. There is evidence that disruption of the circadian system caused by night-shift work results not only in a misalignment between the circadian system and the external light-dark cycle, but also in a state of internal desynchronization between various levels of the circadian system. This is the case between rhythms controlled by the central circadian pacemaker and clock genes expression in tissues such as peripheral blood mononuclear cells, hair follicle cells, and oral mucosa cells. The disruptive effects of atypical work schedules extend beyond the expression profile of canonical circadian clock genes and affects other transcripts of the human genome. In general, after several days of living at night, most rhythmic transcripts in the human genome remain adjusted to a day-oriented schedule, with dampened group amplitudes. In contrast to circadian clock genes and rhythmic transcripts, metabolomics studies revealed that most metabolites shift by several hours when working nights, thus leading to their misalignment with the circadian system. Altogether, these circadian and sleep-wake disturbances emphasize the all-encompassing impact of night-shift work, and can contribute to the increased risk of various medical conditions. Here, we review the latest scientific evidence regarding the effects of atypical work schedules on the circadian system, sleep and alertness of shift-working populations, and discuss their potential clinical impacts.
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Affiliation(s)
- Diane B Boivin
- Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Philippe Boudreau
- Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Anastasi Kosmadopoulos
- Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
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Mannino G, Pernici C, Serio G, Gentile C, Bertea CM. Melatonin and Phytomelatonin: Chemistry, Biosynthesis, Metabolism, Distribution and Bioactivity in Plants and Animals-An Overview. Int J Mol Sci 2021; 22:ijms22189996. [PMID: 34576159 PMCID: PMC8469784 DOI: 10.3390/ijms22189996] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 12/21/2022] Open
Abstract
Melatonin is a ubiquitous indolamine, largely investigated for its key role in the regulation of several physiological processes in both animals and plants. In the last century, it was reported that this molecule may be produced in high concentrations by several species belonging to the plant kingdom and stored in specialized tissues. In this review, the main information related to the chemistry of melatonin and its metabolism has been summarized. Furthermore, the biosynthetic pathway characteristics of animal and plant cells have been compared, and the main differences between the two systems highlighted. Additionally, in order to investigate the distribution of this indolamine in the plant kingdom, distribution cluster analysis was performed using a database composed by 47 previously published articles reporting the content of melatonin in different plant families, species and tissues. Finally, the potential pharmacological and biostimulant benefits derived from the administration of exogenous melatonin on animals or plants via the intake of dietary supplements or the application of biostimulant formulation have been largely discussed.
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Affiliation(s)
- Giuseppe Mannino
- Department of Life Sciences and Systems Biology, Plant Physiology Unit, University of Turin, Via Quarello 15/A, 10135 Turin, Italy; (G.M.); (C.P.)
| | - Carlo Pernici
- Department of Life Sciences and Systems Biology, Plant Physiology Unit, University of Turin, Via Quarello 15/A, 10135 Turin, Italy; (G.M.); (C.P.)
| | - Graziella Serio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy;
| | - Carla Gentile
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy;
- Correspondence: (C.G.); (C.M.B.); Tel.: +39-091-2389-7423 (C.G.); +39-011-670-6361 (C.M.B.)
| | - Cinzia M. Bertea
- Department of Life Sciences and Systems Biology, Plant Physiology Unit, University of Turin, Via Quarello 15/A, 10135 Turin, Italy; (G.M.); (C.P.)
- Correspondence: (C.G.); (C.M.B.); Tel.: +39-091-2389-7423 (C.G.); +39-011-670-6361 (C.M.B.)
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Alaasam VJ, Liu X, Niu Y, Habibian JS, Pieraut S, Ferguson BS, Zhang Y, Ouyang JQ. Effects of dim artificial light at night on locomotor activity, cardiovascular physiology, and circadian clock genes in a diurnal songbird. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 282:117036. [PMID: 33838441 PMCID: PMC8184626 DOI: 10.1016/j.envpol.2021.117036] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/04/2021] [Accepted: 03/28/2021] [Indexed: 05/17/2023]
Abstract
Artificial light is transforming the nighttime environment and quickly becoming one of the most pervasive pollutants on earth. Across taxa, light entrains endogenous circadian clocks that function to synchronize behavioral and physiological rhythms with natural photoperiod. Artificial light at night (ALAN) disrupts these photoperiodic cues and has consequences for humans and wildlife including sleep disruption, physiological stress and increased risk of cardiovascular disease. However, the mechanisms underlying organismal responses to dim ALAN, resembling light pollution, remain elusive. Light pollution exists in the environment at lower levels (<5 lux) than tested in many laboratory studies that link ALAN to circadian rhythm disruption. Few studies have linked dim ALAN to both the upstream regulators of circadian rhythms and downstream behavioral and physiological consequences. We exposed zebra finches (Taeniopygia gutatta) to dim ALAN (1.5 lux) and measured circadian expression of five pacemaker genes in central and peripheral tissues, plasma melatonin, locomotor activity, and biomarkers of cardiovascular health. ALAN caused an increase in nighttime activity and, for males, cardiac hypertrophy. Moreover, downstream effects were detectable after just short duration exposure (10 days) and at dim levels that mimic the intensity of environmental light pollution. However, ALAN did not affect circulating melatonin nor oscillations of circadian gene expression in the central clock (brain) or liver. These findings suggest that dim ALAN can alter behavior and physiology without strong shifts in the rhythmic expression of molecular circadian pacemakers. Approaches that focus on ecologically-relevant ALAN and link complex biological pathways are necessary to understand the mechanisms underlying vertebrate responses to light pollution.
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Affiliation(s)
- Valentina J Alaasam
- Department of Biology, University of Nevada, Reno, Reno, NV, USA; Program of Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Reno, NV, USA.
| | - Xu Liu
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Ye Niu
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Justine S Habibian
- Department of Nutrition, University of Nevada, Reno, Reno, NV, USA; Program of Cellular and Molecular Biology, University of Nevada, Reno, Reno, NV, USA
| | - Simon Pieraut
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Brad S Ferguson
- Department of Nutrition, University of Nevada, Reno, Reno, NV, USA; Center for Biomedical Research Excellence in Molecular and Cellular Signal Transduction in the Cardiovascular System, School of Medicine, University of Nevada, Reno, Reno, NV, USA
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Jenny Q Ouyang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
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Chawla S, Beretoulis S, Deere A, Radenkovic D. The Window Matters: A Systematic Review of Time Restricted Eating Strategies in Relation to Cortisol and Melatonin Secretion. Nutrients 2021; 13:nu13082525. [PMID: 34444685 PMCID: PMC8399962 DOI: 10.3390/nu13082525] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 01/26/2023] Open
Abstract
Time-Restricted Eating is an eating pattern based on the circadian rhythm which limits daily food intake (usually to ≤12 h/day), unique in that no overt restriction is imposed on the quality, nor quantity, of food intake. This paper aimed to examine the effects of two patterns of TRE, traditional TRE, and Ramadan fasting, on two markers of circadian rhythm, cortisol and melatonin. PubMed and Web of Science were searched up to December 2020 for studies examining the effects of time restricted eating on cortisol and melatonin. Fourteen studies met our inclusion criteria. All Ramadan papers found statistically significant decrease in melatonin (p < 0.05) during Ramadan. Two out of the three Ramadan papers noted an abolishing of the circadian rhythm of cortisol (p < 0.05). The non-Ramadan TRE papers did not examine melatonin, and cortisol changes were mixed. In studies comparing TRE to control diets, Stratton et al. found increased cortisol levels in the non-TRE fasting group (p = 0.0018) and McAllister et al. noted no difference. Dinner-skipping resulted in significantly reduced evening cortisol and non-significantly raised morning cortisol. Conversely, breakfast skipping resulted in significantly reduced morning cortisol. This blunting indicates a dysfunctional HPA axis, and may be associated with poor cardio-metabolic outcomes. There is a paucity of research examining the effects of TRE on cortisol and melatonin. The contrasting effect of dinner and breakfast-skipping should be further examined to ascertain whether timing the feeding window indeed has an impact on circadian rhythmicity.
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Affiliation(s)
- Shreya Chawla
- Faculty of Life Sciences and Medicine, King’s College London, London SE1 1UL, UK;
| | - Spyridon Beretoulis
- HOOKE London owned by Health Longevity Optimisation Ltd., London EC1V 3QJ, UK; (S.B.); (A.D.)
| | - Aaron Deere
- HOOKE London owned by Health Longevity Optimisation Ltd., London EC1V 3QJ, UK; (S.B.); (A.D.)
| | - Dina Radenkovic
- HOOKE London owned by Health Longevity Optimisation Ltd., London EC1V 3QJ, UK; (S.B.); (A.D.)
- Buck Institute for Research on Aging, Novato, CA 94945, USA
- Guy’s and St Thomas’ Hospital, Westminster Bridge Road, London SE1 7EH, UK
- Correspondence:
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Lim YC, Hoe VCW, Darus A, Bhoo-Pathy N. Association between night-shift work, sleep quality and health-related quality of life: a cross-sectional study among manufacturing workers in a middle-income setting. BMJ Open 2020; 10:e034455. [PMID: 32895261 PMCID: PMC7477971 DOI: 10.1136/bmjopen-2019-034455] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Night-shift work may adversely affect health. This study aimed to determine the impact of night-shift work on health-related quality of life (HRQoL), and to assess whether sleep quality was a mediating factor. DESIGN A cross-sectional study. SETTING 11 manufacturing factories in Malaysia. PARTICIPANTS 177 night-shift workers aged 40-65 years old were compared with 317 non-night-shift workers. PRIMARY AND SECONDARY OUTCOMES Participants completed a self-administered questionnaire on socio-demographics and lifestyle factors, 12-item Short Form Health Survey V.2 (SF-12v2) and the Pittsburgh Sleep Quality Index (PSQI). The Baron and Kenny's method, Sobel test and multiple mediation model with bootstrapping were applied to determine whether PSQI score or its components mediated the association between night-shift work and HRQoL. RESULTS Night-shift work was associated with sleep impairment and HRQoL. Night-shift workers had significantly lower mean scores in all the eight SF-12 domains (p<0.001). Compared with non-night-shift workers, night-shift workers were significantly more likely to report poorer sleep quality, longer sleep latency, shorter sleep duration, sleep disturbances and daytime dysfunction (p<0.001). Mediation analyses showed that PSQI global score mediated the association between night-shift work and HRQoL. 'Subjective sleep quality' (indirect effect=-0.24, SE=0.14 and bias corrected (BC) 95% CI -0.58 to -0.01) and 'sleep disturbances' (indirect effect=-0.79, SE=0.22 and BC 95% CI -1.30 to -0.42) were mediators for the association between night-shift work and physical well-being, whereas 'sleep latency' (indirect effect=-0.51, SE=0.21 and BC 95% CI -1.02 to -0.16) and 'daytime dysfunction' (indirect effect=-1.11, SE=0.32 and BC 95% CI -1.86 to -0.58) were mediators with respect to mental well-being. CONCLUSION Sleep quality partially explains the association between night-shift work and poorer HRQoL. Organisations should treat the sleep quality of night-shift workers as a top priority area for action to improve their employees' overall wellbeing.
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Affiliation(s)
- Yin Cheng Lim
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Environmental Health Research Centre, Institute Medical Research (IMR), National Institute of Health, Kuala Lumpur, Malaysia
| | - Victor C W Hoe
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Centre for Occupational and Environmental Health, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Azlan Darus
- Social Security Organization, Kuala Lumpur, Malaysia
| | - Nirmala Bhoo-Pathy
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Centre for Epidemiology and Evidence-Based Practice, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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14
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Aarrebo Jensen M, Kjærgaard JB, Petersen JD, Hansen ÅM, Kristiansen J, Garde AH. The urinary 6-sulfatoxymelatonin level after three different work schedules with 2, 4 and 7 consecutive night shifts among Danish police officers. Chronobiol Int 2020; 37:1400-1403. [DOI: 10.1080/07420528.2020.1807560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Marie Aarrebo Jensen
- Department of Psychosocial work environment, National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Julie Boye Kjærgaard
- Department of Psychosocial work environment, National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Jindong Ding Petersen
- Research Unit for General Practice, Department of Public Health, University of Southern Denmark, Odense, Denmark
- Research Unit for General Practice, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Åse Marie Hansen
- Department of Psychosocial work environment, National Research Centre for the Working Environment, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Kristiansen
- Department of Psychosocial work environment, National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Anne Helene Garde
- Department of Psychosocial work environment, National Research Centre for the Working Environment, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
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15
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Arafa A, Eshak ES, Iso H, Muraki I, Tamakoshi A. Night Work, Rotating Shift Work and the Risk of Cancer in Japanese Men and Women: the JACC Study. J Epidemiol 2020; 31:585-592. [PMID: 32801280 PMCID: PMC8593580 DOI: 10.2188/jea.je20200208] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Limited epidemiological evidence has suggested a positive relationship between night shift work and the risk of cancer. Herein, we investigated the prospective association between different forms of work schedule and the risk of numerous cancers and all-cause cancer among Japanese men and women. Methods This cohort study included 45,390 working men and women aged 40–79 years and registered in the Japan Collaborative Cohort Study (JACC Study). The Cox proportional hazards models were used to calculate the hazard ratios (HRs) and their 95% confidence intervals (CIs) for incident cancer among those who reported engagement in night work and rotating shift work for their longest occupations compared with day work. Results Within a median follow-up duration of 14.2 years, 2,283 (9.4%) men and 1,309 (4.5%) women developed cancer. Among men, rotating shift work was significantly associated with increased risk of esophageal cancer (HR 2.47; 95% CI, 1.42–4.31) and decreased risk of liver cancer (HR 0.54; 95% CI, 0.30–0.98). Also, rotating shift work tended to be associated with the increased risk of prostate cancer (HR 1.42; 95% CI, 0.95–2.12). Night work and rotating shift work were not related to the risk of all-cause cancer in either sex. Conclusion Rotating shift work might contribute to the increased risk of esophageal cancer and prostate cancer and the decreased risk of liver cancer among Japanese men.
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Affiliation(s)
- Ahmed Arafa
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine.,Department of Public Health, Faculty of Medicine, Beni-Suef University
| | - Ehab S Eshak
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine.,Department of Public Health, Faculty of Medicine, Minia University
| | - Hiroyasu Iso
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine
| | - Isao Muraki
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine
| | - Akiko Tamakoshi
- Department of Public Health, Graduate School of Medicine, Hokkaido University
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16
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Marti AR, Pedersen TT, Wisor JP, Mrdalj J, Holmelid Ø, Patil S, Meerlo P, Bramham CR, Grønli J. Cognitive function and brain plasticity in a rat model of shift work: role of daily rhythms, sleep and glucocorticoids. Sci Rep 2020; 10:13141. [PMID: 32753733 PMCID: PMC7403587 DOI: 10.1038/s41598-020-69969-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
Many occupations require operations during the night-time when the internal circadian clock promotes sleep, in many cases resulting in impairments in cognitive performance and brain functioning. Here, we use a rat model to attempt to identify the biological mechanisms underlying such impaired performance. Rats were exposed to forced activity, either in their rest-phase (simulating night-shift work; rest work) or in their active-phase (simulating day-shift work; active work). Sleep, wakefulness and body temperature rhythm were monitored throughout. Following three work shifts, spatial memory performance was tested on the Morris Water Maze task. After 4 weeks washout, the work protocol was repeated, and blood and brain tissue collected. Simulated night-shift work impaired spatial memory and altered biochemical markers of cerebral cortical protein synthesis. Measures of daily rhythm strength were blunted, and sleep drive increased. Individual variation in the data suggested differences in shift work tolerance. Hierarchical regression analyses revealed that type of work, changes in daily rhythmicity and changes in sleep drive predict spatial memory performance and expression of brain protein synthesis regulators. Moreover, serum corticosterone levels predicted expression of brain protein synthesis regulators. These findings open new research avenues into the biological mechanisms that underlie individual variation in shift work tolerance.
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Affiliation(s)
- Andrea R Marti
- Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway. .,Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway.
| | - Torhild T Pedersen
- Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway
| | - Jonathan P Wisor
- College of Medicine, Washington State University, Spokane, WA, USA
| | - Jelena Mrdalj
- Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway
| | - Øystein Holmelid
- Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway
| | - Sudarshan Patil
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Peter Meerlo
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Clive R Bramham
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Janne Grønli
- Bergen Stress and Sleep Group, Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Jonas Liesvei 91, 5009, Bergen, Norway
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Lim GY, Jang TW, Sim CS, Ahn YS, Jeong KS. Comparison of Cortisol level by Shift Cycle in Korean Firefighters. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E4760. [PMID: 32630691 PMCID: PMC7370292 DOI: 10.3390/ijerph17134760] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022]
Abstract
(1) Study Objectives: By investigating the change of cortisol levels during shift cycles among professional firefighters in Korea, this study aims to evaluate the difference between individuals' stress response and the recovery of their circadian rhythm after working night shifts. (2) Methods: A total of 325 shift firefighters, who were working in 3, 6, 9, or 21 day cycles, participated in the study. Their urinary and serum cortisol levels were measured during the day (09-18), during the night (18-09), and every 24 h (09-09) per shift cycle, and adjustments were made for confounding factors. (3) Results: Serum cortisol levels were significantly increased after working during the night or for 24 h compared with that of working throughout the day. However, whether working night or 24 h shifts, the serum cortisol levels were undoubtedly different based on the 3, 6, 9, or 21 day cycles. In all shift cycles, the urinary cortisol level decreased during the night or throughout the 24 h shifts compared with sleeping during this time, but this was considered to be significantly applicable only to those working in 21 day cycles. Additionally, in serial measurements, the recovery of urinary cortisol secretion after a night or 24 h shift was successful for individuals working in 9 day cycles, but the recovery was delayed for those working in 6 or 21 day cycles. (4) Conclusions: After analyzing the urine cortisol levels, the study indicates that only subjects working in 9 day cycles fully recovered their circadian rhythm while those working in 6 day or 21 day cycles did not completely recover. Therefore, it is important to recognize how stressful night shifts can be, and it is crucial to enhance firefighters' current shift cycles in order to allow sufficient recovery of their circadian rhythm as well as the prevention of disrupting their circadian rhythm after working at night. Further research is necessary to take into account the amount of work load, the challenges of being sleep deprived, and the individual's capacity to overcome sleepiness.
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Affiliation(s)
- Ga-Young Lim
- Department of Public Health, Hanyang University, Seoul 04763, Korea;
| | - Tae-Won Jang
- Department of Occupational and Environmental Medicine, College of Medicine, Hanynag University, Seoul 04763, Korea;
| | - Chang-Sun Sim
- Department of Occupational and Environmental Medicine, College of Medicine, University of Ulsan, Ulsan 44033, Korea;
| | - Yeon Soon Ahn
- Department of Preventive Medicine, Wonju College of Medicine, Yonsei University, Wonju 26426, Korea;
| | - Kyoung Sook Jeong
- Department of Occupational and Environmental Medicine, Wonju Severance Christian Hospital, Wonju 26426, Korea
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18
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Bukowska-Damska A, Skowronska-Jozwiak E, Kaluzny P, Lewinski A, Peplonska B. Night shift work and osteoporosis among female blue-collar workers in Poland - a pilot study. Chronobiol Int 2020; 37:910-920. [DOI: 10.1080/07420528.2020.1763381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
| | - Elzbieta Skowronska-Jozwiak
- Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Lodz, Poland
- Department of Endocrinology and Metabolic Diseases, Polish Mother’s Memorial Hospital - Research Institute, Lodz, Poland
| | - Pawel Kaluzny
- Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - Andrzej Lewinski
- Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Lodz, Poland
- Department of Endocrinology and Metabolic Diseases, Polish Mother’s Memorial Hospital - Research Institute, Lodz, Poland
| | - Beata Peplonska
- Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland
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19
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Satyanarayanan SK, Chien YC, Chang JPC, Huang SY, Guu TW, Su H, Su KP. Melatonergic agonist regulates circadian clock genes and peripheral inflammatory and neuroplasticity markers in patients with depression and anxiety. Brain Behav Immun 2020; 85:142-151. [PMID: 30851380 DOI: 10.1016/j.bbi.2019.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/25/2019] [Accepted: 03/05/2019] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Circadian dysfunction is a core manifestation and a risk factor for psychiatric disorders. Ramelteon (RMT), a melatonin receptor agonist, has been shown to induce sleep phase shifts and has been used to normalize sleep onset time. RMT has been used in sleep disorders, depression and anxiety. In this study, we aimed to investigate the effects of RMT in regulating gene expression profiles of the circadian clock and peripheral markers of inflammation and neuroplasticity. METHODS Sixteen patients with a diagnosis of primary insomnia comorbid with depression and anxiety and ten healthy controls were recruited in an 8-week open-label trial. The patients with primary insomnia received RMT 8 mg/day. The morning expression profiles of 15 core clock genes from peripheral blood mononuclear cells (PBMCs), urine and plasma levels of melatonin and its metabolite levels, and plasma inflammatory markers and neurotrophin levels were evaluated at baseline, 4th and 8th week of RMT treatment. RESULTS RMT treatment was associated with significant clinical improvement in depression scores at 8th week (Hamilton depression rating scale scores (Mean ± SEM) from 21.5 ± 2.44 to 14.31 ± 2.25, p ≤ 0.05). The overall poor sleep quality (Pittsburgh sleep quality index) of the patient group significantly improved (p ≤ 0.05) following RMT treatment. The mRNA level analysis showed a significant association between RMT treatment and alterations of the nine core circadian genes (CLOCK, PER1, PER2, CRY1, CRY2, NR1D1, NR1D2, DEC1 and TIMELESS) in the patient group when compared with the control group (p ≤ 0.05). Compared with the controls, the patient group had a decrease in neurotrophins (brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and beta-nerve growth factor; p ≤ 0.05) but an increase in pro-inflammatory cytokine levels (interleukin-6, interleukin-1b, tumour necrosis factor-alpha and interferon gamma; p ≤ 0.05); RMT treatment normalized the levels of neurotrophins and cytokine levels. CONCLUSION RMT treatment is able to restore phase-shifted melatonin markers, normalized the altered expression of the circadian genes, the levels of inflammatory cytokines and neurotrophins in patients with insomnia comorbid anxiety and depression.
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Affiliation(s)
- Senthil Kumaran Satyanarayanan
- Department of Psychiatry & Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan; State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Yu-Chuan Chien
- Department of Psychiatry & Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan; Division of Psychiatry, Departments of Internal Medicine, China Medical University Beigang Hospital, Yunlin, Taiwan
| | - Jane Pei-Chen Chang
- Department of Psychiatry & Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan; Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; College of Medicine, China Medical University, Taichung, Taiwan
| | - Shih-Yi Huang
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei, Taiwan
| | - Ta-Wei Guu
- Department of Psychiatry & Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan; Division of Psychiatry, Departments of Internal Medicine, China Medical University Beigang Hospital, Yunlin, Taiwan
| | - Huanxing Su
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Kuan-Pin Su
- Department of Psychiatry & Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan; Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; College of Medicine, China Medical University, Taichung, Taiwan.
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20
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Ferri GM, Cavone D, Intranuovo G, Macinagrossa L. Healthy Diet and Reduction of Chronic Disease Risks of Night Shift Workers. Curr Med Chem 2019; 26:3521-3541. [PMID: 28730970 DOI: 10.2174/0929867324666170720160632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND The large increase in epidemiological studies on night shift work is due to the important effects of night shift work on workers' health and psychophysical wellbeing. The short-term effects-insomnia, difficulties in managing work and private life, lower work performance, and more work and extra-work accidents-are easily studied. However, there are several long-term effects that are difficult to study because of the need for detailed exposure assessment and the long latency periods of these diseases. OBJECTIVE The aim was to collect epidemiologic evidence of diseases in night shift workers, describing their biological pathways and a set of dietary guidelines. METHODS This is a review on diet and health effects in night shift workers. RESULTS Significant increases in the rate ratios and hazard ratios of different diseases were associated with modified eating behaviours and poor eating habits among night shift workers. Night shift work is a risk factor for disruption of the circadian rhythms and for some genetic deregulation because it produces the inversion of the sleep/wake cycle and modifies the alternation between activity and rest. CONCLUSION A healthy diet and improved dietary practices, together with other factors, can reduce shift workers' chronic disease risk. The literature showed the importance of eating behaviour in order to prevent diseases in these workers; therefore, educational programmes are necessary to encourage several important lifestyle changes. The target of our future research will be the role of food components in some dietetic habits for the prevention of disease in night shift workers.
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Affiliation(s)
- G M Ferri
- Interdisciplinary Department of Medicine (DIM), Section "B. Ramazzini", Unit of Occupational Medicine, University Regional Hospital "Policlinico - Giovanni XXIIIth", Bari, Italy
| | - D Cavone
- Interdisciplinary Department of Medicine (DIM), Section "B. Ramazzini", Unit of Occupational Medicine, University Regional Hospital "Policlinico - Giovanni XXIIIth", Bari, Italy
| | - G Intranuovo
- Interdisciplinary Department of Medicine (DIM), Section "B. Ramazzini", Unit of Occupational Medicine, University Regional Hospital "Policlinico - Giovanni XXIIIth", Bari, Italy
| | - L Macinagrossa
- Interdisciplinary Department of Medicine (DIM), Section "B. Ramazzini", Unit of Occupational Medicine, University Regional Hospital "Policlinico - Giovanni XXIIIth", Bari, Italy
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Khosravipour M, Shah Mohammadi M. The effects of exposure to night shift work on liver function: A cross-sectional study with emphasis of alkaline phosphatase enzyme. Chronobiol Int 2019; 37:142-145. [DOI: 10.1080/07420528.2019.1684936] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Masoud Khosravipour
- Research Center for Environmental Determinants of Health (RCEDH), Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Occupational Health Engineering, School of Health, Kermanshah University of Medical Science, Kermanshah, Iran
| | - Mostafa Shah Mohammadi
- Department of Occupational Health Engineering, School of Health, Kermanshah University of Medical Science, Kermanshah, Iran
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Khosravipour M, Shahmohammadi M, Athar HV. The effects of rotating and extended night shift work on the prevalence of metabolic syndrome and its components. Diabetes Metab Syndr 2019; 13:3085-3089. [PMID: 31765983 DOI: 10.1016/j.dsx.2019.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/11/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Some studies indicated night shift work can be associated with the higher risk of metabolic syndrome (MetS). However, the effect of both rotating and extended night shift work (12-hr rotating night) on MetS has not well-known. We aimed to examine and clarify the association among petrochemical workers. METHODS We recruited 1575 eligible workers in this study. According to shift work schedules the participants were divided into following groups: 12-hr fixed day and 12-hr rotating night. Biochemical data, including fasting blood sugar and lipid panel (TC, TG, LDL, and HDL) were determined by blood tests. Demographic data was obtained by interview at the time of blood pressure and anthropometric indices measurements. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) was applied to identify subjects with MetS. The Logistic regression models were used to predict risk of MetS and its components between study groups. RESULTS The prevalence of MetS was showed 18.4% (290/1575). We found a significant difference between study groups in the prevalence of MetS (p < 0.05). The odds ratios (ORs) and 95% confidence intervals (CIs) in the 12-hr rotating night group in comparison to the 12-hr fixed day shift group according to unadjusted and full adjusted logistic regression models were estimated 1.26 (0.96, 1.65) and 1.34 (1.01, 1.76), respectively. Among MetS components, we observed the significant higher risk in TG and HDL (P < 0.05). CONCLUSION This study suggests 12-hr rotating night shift as the high-risk group for MetS. More studies needed to confirm our findings.
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Affiliation(s)
- Masoud Khosravipour
- Research Center for Environmental Determinants of Health (RCEDH), Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Occupational Health Engineering, School of Public Health, Kermanshah University of Medical Science, Kermanshah, Iran; Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mostafa Shahmohammadi
- Department of Occupational Health Engineering, School of Public Health, Kermanshah University of Medical Science, Kermanshah, Iran; Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hossein Valadi Athar
- Department of Occupational Health Engineering, School of Public Health, Kermanshah University of Medical Science, Kermanshah, Iran; Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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Copertaro A, Bracci M. Working against the biological clock: a review for the Occupational Physician. INDUSTRIAL HEALTH 2019; 57:557-569. [PMID: 30799323 PMCID: PMC6783289 DOI: 10.2486/indhealth.2018-0173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 12/27/2018] [Indexed: 05/28/2023]
Abstract
The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes the molecular biological clock found in every cell of most peripheral tissues. The human circadian rhythm is largely based on the light-dark cycle. In night shift workers, alteration of the cycle and inversion of the sleep-wake rhythm can result in disruption of the biological clock and induce adverse health effects. This paper offers an overview of the main physiological mechanisms that regulate the circadian rhythm and of the health risks that are associated with its perturbation in shift and night workers. The Occupational Physician should screen shift and night workers for clinical symptoms related to the perturbation of the biological clock and consider preventive strategies to reduce the associated health risks.
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Affiliation(s)
| | - Massimo Bracci
- Occupational Medicine, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, Italy
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Sandoe CH, Sasikumar S, Lay C, Lawler V. The Impact of Shift Work on Migraine: A Case Series and Narrative Review. Headache 2019; 59:1631-1640. [DOI: 10.1111/head.13622] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Claire H. Sandoe
- Center for Headache, Division of Neurology, Women’s College Hospital University of Toronto Toronto Canada
| | - Sanskriti Sasikumar
- Center for Headache, Division of Neurology, Women’s College Hospital University of Toronto Toronto Canada
| | - Christine Lay
- Center for Headache, Division of Neurology, Women’s College Hospital University of Toronto Toronto Canada
| | - Valerie Lawler
- Center for Headache, Division of Neurology, Women’s College Hospital University of Toronto Toronto Canada
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Higher Number of Night Shifts Associates with Good Perception of Work Capacity and Optimal Lung Function but Correlates with Increased Oxidative Damage and Telomere Attrition. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8327629. [PMID: 31111068 PMCID: PMC6487156 DOI: 10.1155/2019/8327629] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/16/2019] [Accepted: 04/01/2019] [Indexed: 12/11/2022]
Abstract
Sleep deprivation and the consequent circadian clock disruption has become an emergent health question being associated with premature aging and earlier chronic diseases onset. Night-shift work leads to circadian clock misalignment, which is linked to several age-related diseases. However, mechanisms of this association are not well understood. Aim of this study is to explore in night-shift workers early indicators of oxidative stress response and biological aging [oxidized/methylated DNA bases and leukocytes telomere length (LTL)] and late indicators of functional aging [lung function measurements (FEV1 and FVC)] in relation to personal evaluation of work capacity, measured by work ability index (WAI). One hundred fifty-five hospital workers were studied within the framework of a cross-sectional study. We collected physiological, pathological, and occupational history including pack-years, alcohol consumption, physical activity, and night shifts, together with blood and urine samples. Relationships were appraised by univariate and multivariate ordered-logistic regression models. We found that workers with good and excellent WAI present higher FEV1 (p< 0.01) and number of night-work shifts (p<0.05), but they reveal higher urinary levels of 8-oxoGua (p<0.01) and shorter LTL (p<0.05). We confirmed that higher work ability was prevalent among chronological younger workers (p<0.05), who have also a significant reduced number of diseases, particularly chronic (p<0.01) and musculoskeletal diseases (p<0.01). The new findings which stem from our work are that subjects with the highest work ability perception may have more demanding and burdensome tasks; they in fact present the highest number of night-shift work and produce unbalanced oxidative stress response that might induce premature aging.
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Yau A, Haque M. Shiftwork Association with Cardiovascular Diseases and Cancers Among Healthcare Workers: A Literature Review. Medeni Med J 2019; 34:387-395. [PMID: 32821466 PMCID: PMC7433719 DOI: 10.5222/mmj.2019.54775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023] Open
Abstract
The round-the-clock demands of healthcare services, coupled with the shortage of healthcare providers in many parts of the world, have made shiftwork widespread among healthcare workers. Understanding how to mitigate unfavourable effects of shiftwork on well-being is essential to improve health promotion, to prevent disease prevention, and to increase quality of life. This comprehensive review aims to present evidence linking shiftwork with cardiovascular diseases and cancers among healthcare workers. Several studies have demonstrated evidence indicating the relationship between long-term exposure to shiftwork tempo and a higher risk of cardiovascular diseases. Health workers are increasingly witnesing unfavourable effects of shiftwork on their health state. Shiftwork disturbs circadian rhythm and cardiopulmonary processes, leading to adverse health outcomes. Increasing prevalence of shiftwork in healthcare industries due to population expansion and public health threat of cancers call for investigation towards a better understanding of the underlying mechanism of shiftwork-induced diseases. The shift work period has been considered in different studies using various criteria, resulting in inconsistent definition of measurement criteria leading to misclassification of the study population. There is a need for a more considerable and holistic effort towards standardization of shiftwork definition and conduct an assessment to establish a more conveniently appliacable framework for intervention strategies.
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Affiliation(s)
- Adamu Yau
- Naresuan University, Faculty of Pharmaceutical Sciences, Phitsanulok, Thailand Texas A&M University, School of Public Health, Health Science Center, Department of Epidemiology and Biostatistics, Texas, USA.,Bayero University, Faculty of Pharmaceutical Sciences, Department of Pharmacology and Therapeutics, Kano, Nigeria
| | - Mainul Haque
- Universiti Pertahanan Nasional Malaysia, Faculty of Medicine and Defence Health, Department of Pharmacology, Kem Perdana Sungai Besi, 57000 Kuala Lumpur, Malaysia
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Lohman EB, Pacheco GR, Gharibvand L, Daher N, Devore K, Bains G, AlAmeri M, Berk LS. The immediate effects of cervical spine manipulation on pain and biochemical markers in females with acute non-specific mechanical neck pain: a randomized clinical trial. J Man Manip Ther 2018; 27:186-196. [PMID: 30935335 PMCID: PMC7025692 DOI: 10.1080/10669817.2018.1553696] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Study Design: Randomized clinical trial with pre-test, post-test control group design. Objectives: To examine the immediate effects of cervical spinal manipulation (CSM) on serum concentration of biochemical markers (oxytocin, neurotensin, orexin A, and cortisol). Background: Several studies have found an association between spinal manipulation (SM) and pain perception. However, the mechanism by which SM modulates pain remains undefined. Methods: Twenty-eight female subjects with non-specific mechanical neck pain were randomly assigned to one of two interventions (CSM versus sham CSM). Blood samples were drawn before and immediately after the respective interventions. Oxytocin, neurotensin, orexin A, and cortisol were measured from the blood and serum using the Milliplex Map Magnetic Bead Panel Immunoassay on the Luminex 200 Platform. Results: In the CSM group, there were significant increases in pre- versus post-manipulation mean oxytocin (154.5 ± 60.1 vs. 185.1 ± 75.6, p = .012); neurotensin (116.0 ± 26.5 vs.136.4 ± 34.1, p < . 001); orexin A (52.2 ± 31.1 vs. 73.8 ± 38.8, p < .01) serum concentration; but no significant differences in mean cortisol (p = .052) serum concentration. In the sham group, there were no significant differences in any of the biomarkers (p > .05). Conclusion: The results of the current study suggest that the mechanical stimuli provided through a CSM may modify neuropeptide expression by immediately increasing the serum concentration of nociception-related biomarkers (oxytocin, neurotensin, orexin A, but not cortisol) in the blood of female subjects with non-specific mechanical neck pain.
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Affiliation(s)
- E B Lohman
- a School of Allied Health Professions, Physical Therapy Department, Loma Linda University , Loma Linda , CA , USA
| | - G R Pacheco
- a School of Allied Health Professions, Physical Therapy Department, Loma Linda University , Loma Linda , CA , USA
| | - L Gharibvand
- b School of Allied Health Professions, Allied Health Studies Department, Loma Linda University , Loma Linda , CA , USA
| | - N Daher
- b School of Allied Health Professions, Allied Health Studies Department, Loma Linda University , Loma Linda , CA , USA
| | - K Devore
- b School of Allied Health Professions, Allied Health Studies Department, Loma Linda University , Loma Linda , CA , USA
| | - G Bains
- b School of Allied Health Professions, Allied Health Studies Department, Loma Linda University , Loma Linda , CA , USA
| | - M AlAmeri
- a School of Allied Health Professions, Physical Therapy Department, Loma Linda University , Loma Linda , CA , USA
| | - L S Berk
- b School of Allied Health Professions, Allied Health Studies Department, Loma Linda University , Loma Linda , CA , USA.,c School of Medicine, Department of Pathology and Human Anatomy, Loma Linda University , Loma Linda , CA , USA
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Sex Differences in the Association between Night Shift Work and the Risk of Cancers: A Meta-Analysis of 57 Articles. DISEASE MARKERS 2018; 2018:7925219. [PMID: 30598709 PMCID: PMC6287141 DOI: 10.1155/2018/7925219] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/25/2018] [Indexed: 01/20/2023]
Abstract
Objectives To identify the association between night shift work and the risk of various cancers with a comprehensive perspective and to explore sex differences in this association. Methods We searched PubMed, Embase, and Web of Science for studies on the effect of night shift work on cancer, including case-control, cohort, and nested case-control studies. We computed risk estimates with 95% confidence intervals (CIs) in a random or fixed effects model and quantified heterogeneity using the I 2 statistic. Subgroup, metaregression, and sensitivity analyses were performed to explore potential sources of heterogeneity. Contour-enhanced funnel plots and the trim and fill method were used together to analyze bias. Linear dose-response analysis was used to quantitatively estimate the accumulative effect of night shift work on the risk of cancer. Results Fifty-eight studies were eligible for our meta-analysis, including 5,143,838 participants. In the random effects model, the pooled odds ratio (OR) of cancers was 1.15 (95% CI = 1.08-1.22, P < 0.001; I 2 = 76.2%). Night shift work increased the cancer risk in both men (OR = 1.14, 95% CI = 1.05-1.25, P = 0.003) and women (OR = 1.12, 95% CI = 1.04-1.20, P = 0.002). Subgroup analyses showed that night shift work positively increased the risk of breast (OR = 1.22, 95% CI = 1.08-1.38), prostate (OR = 1.26, 95% CI = 1.05-1.52), and digestive system (OR = 1.15, 95% CI = 1.01-1.32) cancers. For every 5 years of night shift work, the cancer risk increased by 3.2% (OR = 1.032, 95% CI = 1.013-1.051). Conclusion This is the first meta-analysis identifying the positive association between night shift work and the risk of cancer and verifying that there is no sex difference in the effect of night shift work on cancer risk. Cancer risk increases with cumulative years of night shift work.
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Bukowska-Damska A, Skowronska-Jozwiak E, Peplonska B. Night shift work and osteoporosis: evidence and hypothesis. Chronobiol Int 2018; 36:171-180. [PMID: 30311808 DOI: 10.1080/07420528.2018.1528553] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Osteoporosis is an important public health problem worldwide. Among the countries with a very high population risk of fractures, there are those with the highest level of economic development. Osteoporotic fractures are the main cause of disability among elderly people, and the resultant disabilities require particularly large financial support associated not only with the direct treatment of the fracture but also with the necessity for long-term rehabilitation and care for the disabled person. Many well-established factors can have impact on bone mass and fracture risk. Recently, it has been hypothesized that working during nighttime which leads to endocrine disorders may have an indirect impact on bone physiology among night shift workers. Therefore, it can be presumed that the night shift work may contribute to the etiology of osteoporosis. The aim of our work was to make a review of the epidemiological evidence on the association between night shift work and bone mineral density or fracture risk as well as to discuss the potential biological mechanisms linking the work under this system with the development of osteoporosis. We have identified only four studies investigating the association between system of work and bone mineral density or fracture risk among workers. The findings of three out of four studies support the hypothesis. None of the studies has investigated a potential relationship between night shift work and bone turnover markers. Given that there have been no epidemiological studies in European countries that would concern working populations and the noticeable difference in the risk of osteoporosis between communities, further studies are warranted to elucidate the problem. It is presumed that further in-depth studies will not only identify the underlying factors of the disease but also contribute to developing guidelines for policy makers and employers for primary prevention of osteoporosis in workplace.
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Affiliation(s)
- Agnieszka Bukowska-Damska
- a Department of Environmental Epidemiology , Nofer Institute of Occupational Medicine , Lodz , Poland
| | - Elzbieta Skowronska-Jozwiak
- b Department of Endocrinology and Metabolic Diseases , Medical University of Lodz , Lodz , Poland.,c Department of Endocrinology and Metabolic Diseases , Polish Mother's Memorial Hospital - Research Institute , Lodz , Poland
| | - Beata Peplonska
- a Department of Environmental Epidemiology , Nofer Institute of Occupational Medicine , Lodz , Poland
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Li J, Bidlingmaier M, Petru R, Pedrosa Gil F, Loerbroks A, Angerer P. Impact of shift work on the diurnal cortisol rhythm: a one-year longitudinal study in junior physicians. J Occup Med Toxicol 2018; 13:23. [PMID: 30123312 PMCID: PMC6090626 DOI: 10.1186/s12995-018-0204-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/11/2018] [Indexed: 01/03/2023] Open
Abstract
Background Cumulative epidemiological evidence suggests that shift work exerts harmful effects on human health. However, the physiological mechanisms are not well understood. This study aimed to examine the impact of shift work on the dysregulation of the hypothalamic-pituitary-adrenal axis, i.e. diurnal cortisol rhythm. Methods Seventy physicians with a mean age 30 years participated in this one-year longitudinal study. Working schedules, either shift work or regular schedules with day shift, were assessed at baseline. Salivary cortisol samples were collected on two consecutive regular working days, four times a day (including waking, + 4 h, + 8 h, and + 16 h), at both baseline and the one-year follow-up. The diurnal cortisol decline (slope) and total cortisol concentration (area under the curve, AUC) were calculated. Results After adjusting for cortisol secretion at baseline and numerous covariates, shift work at baseline significantly predicted a steeper slope (p < 0.01) and a larger AUC (p < 0.05) of diurnal cortisol rhythm at follow-up in this sample of physicians. In particular, waking cortisol at follow-up was significantly higher among those engaged in shift work than day shift (p < 0.01). Conclusions Our findings support the notion that shift work changes the diurnal cortisol pattern, and is predictive of increased cortisol secretion consequently in junior physicians.
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Affiliation(s)
- Jian Li
- 1Institute of Occupational, Social and Environmental Medicine, Centre for Health and Society, Faculty of Medicine, University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Martin Bidlingmaier
- 2Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-University, Munich, Germany
| | - Raluca Petru
- 3Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Ludwig-Maximilians-University, Munich, Germany
| | - Francisco Pedrosa Gil
- Clinic for Psychiatry, Psychotherapy and Psychosomatics, Helios Vogtland Clinical Center, Plauen, Germany
| | - Adrian Loerbroks
- 1Institute of Occupational, Social and Environmental Medicine, Centre for Health and Society, Faculty of Medicine, University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Peter Angerer
- 1Institute of Occupational, Social and Environmental Medicine, Centre for Health and Society, Faculty of Medicine, University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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Lim YC, Hoe VCW, Darus A, Bhoo-Pathy N. Association between night-shift work, sleep quality and metabolic syndrome. Occup Environ Med 2018; 75:716-723. [DOI: 10.1136/oemed-2018-105104] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/29/2018] [Accepted: 07/09/2018] [Indexed: 11/03/2022]
Abstract
ObjectivesOccupational factors, particularly night-shift work, are attracting growing interest as a possible determinant of metabolic syndrome (MetS). This study aimed to determine the association between night-shift work and MetS, and assess whether sleep quality is a mediating factor.MethodsA cross-sectional study was conducted among Malaysian manufacturing workers, aged 40–65 years old. They completed a self-administered questionnaire on sociodemographics, lifestyle and family history, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Waist circumference, blood pressure, fasting blood sugar, triglycerides and high-density lipoprotein levels were measured. Baron and Kenny’s method, Sobel test and multiple mediation models with bootstrapping were used to determine whether the PSQI global score or its components mediated the association between night-shift work and MetS.ResultsOf the 494 participants, 177 (36%) worked night shift and 51% were men. The prevalence of MetS was 37%. Night-shift work was independently associated with a twofold increase in the risk of MetS (adjusted OR: 1.92, 95% CI 1.24 to 2.97). However, the association between night-shift work and MetS did not appear to be modified by sex. Night-shift workers also reported significantly poorer sleep quality, longer sleep latency, shorter sleep duration, sleep disturbances and daytime dysfunction. Robust mediation analysis nonetheless showed that neither PSQI global score nor its components mediated the association between night-shift work and MetS.ConclusionEarly screening and management of MetS and the development of programmes to improve sleep quality should be carried out among night-shift workers. Future research should investigate other modifiable mediators linking night-shift work and MetS.
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Tapia M, Wulff-Zottele C, De Gregorio N, Lang M, Varela H, Josefa Serón-Ferré M, Vivaldi EA, Araneda OF, Silva-Urra J, Gunga HC, Behn C. Melatonin Relations With Respiratory Quotient Weaken on Acute Exposure to High Altitude. Front Physiol 2018; 9:798. [PMID: 30008674 PMCID: PMC6034204 DOI: 10.3389/fphys.2018.00798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 06/07/2018] [Indexed: 12/17/2022] Open
Abstract
High altitude (HA) exposure may affect human health and performance by involving the body timing system. Daily variations of melatonin may disrupt by HA exposure, thereby possibly affecting its relations with a metabolic parameter like the respiratory quotient (RQ). Sea level (SL) volunteers (7 women and 7 men, 21.0 ± 2.04 y) were examined for daily changes in salivary melatonin concentration (SMC). Sampling was successively done at SL (Antofagasta, Chile) and, on acute HA exposure, at nearby Caspana (3,270 m asl). Saliva was collected in special vials (Salimetrics Oral Swab, United Kingdom) at sunny noon (SMCD) and in the absence of blue light at midnight (SMCN). The samples were obtained after rinsing the mouth with tap water and were analyzed for SMC by immunoassay (ELISA kit; IBL International, Germany). RQ measurements (n = 12) were realized with a portable breath to breath metabolic system (OxiconTM Mobile, Germany), between 8:00 PM and 10:00 PM, once at either location. At SL, SMCD, and SMCN values (mean ± SD) were, respectively, 2.14 ± 1.30 and 11.6 ± 13.9 pg/ml (p < 0.05). Corresponding values at HA were 8.83 ± 12.6 and 13.7 ± 16.7 pg/ml (n.s.). RQ was 0.78 ± 0.07 and 0.89 ± 0.08, respectively, at SL and HA (p < 0.05). Differences between SMCN and SMCD (SMCN-SMCD) strongly correlate with the corresponding RQ values at SL (r = -0.74) and less tight at HA (r = -0.37). Similarly, mean daily SMC values (SMC) tightly correlate with RQ at SL (r = -0.79) and weaker at HA (r = -0.31). SMCN-SMCD, as well as, SMC values at SL, on the other hand, respectively, correlate with the corresponding values at HA (r = 0.71 and r = 0.85). Acute exposure to HA appears to loosen relations of SMC with RQ. A personal profile in daily SMC variation, on the other hand, tends to be conserved at HA.
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Affiliation(s)
- Marcelo Tapia
- Owl Capacitaciones y Asesorías SpA, Antofagasta, Chile
| | | | - Nicole De Gregorio
- Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Morin Lang
- Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Héctor Varela
- Facultad de Ciencias Básicas, Universidad de Antofagasta, Antofagasta, Chile
| | | | - Ennio A Vivaldi
- Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Oscar F Araneda
- Facultad de Medicina, Universidad de los Andes, Santiago, Chile
| | - Juan Silva-Urra
- Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Hanns-Christian Gunga
- Center for Space Medicine and Extreme Environments, Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Claus Behn
- Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Facultad de Medicina, Universidad San Sebastián, Santiago, Chile
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Alaasam VJ, Duncan R, Casagrande S, Davies S, Sidher A, Seymoure B, Shen Y, Zhang Y, Ouyang JQ. Light at night disrupts nocturnal rest and elevates glucocorticoids at cool color temperatures. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:465-472. [PMID: 29766666 DOI: 10.1002/jez.2168] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 04/19/2018] [Accepted: 04/25/2018] [Indexed: 12/16/2022]
Abstract
Nighttime light pollution is quickly becoming a pervasive, global concern. Since the invention and proliferation of light-emitting diodes (LED), it has become common for consumers to select from a range of color temperatures of light with varying spectra. Yet, the biological impacts of these different spectra on organisms remain unclear. We tested if nighttime illumination of LEDs, at two commercially available color temperatures (3000 and 5000 K) and at ecologically relevant illumination levels affected body condition, food intake, locomotor activity, and glucocorticoid levels in zebra finches (Taeniopygia guttata). We found that individuals exposed to 5000 K light had higher rates of nighttime activity (peaking after 1 week of treatment) compared to 3000 K light and controls (no nighttime light). Birds in the 5000 K treatment group also had increased corticosterone levels from pretreatment levels compared to 3000 K and control groups but no changes in body condition or food intake. Individuals that were active during the night did not consequently decrease daytime activity. This study adds to the growing evidence that the spectrum of artificial light at night is important, and we advocate the use of nighttime lighting with warmer color temperatures of 3000 K instead of 5000 K to decrease energetic costs for avian taxa.
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Affiliation(s)
| | - Richard Duncan
- Department of Biology, University of Nevada, Reno, Nevada
| | | | - Scott Davies
- Department of Biological Sciences, Quinnipiac University, Hamden, Connecticut
| | - Abhijaat Sidher
- Department of Biology, University of Nevada, Reno, Nevada.,Department of Electrical and Biomedical Engineering, University of Nevada, Reno, Nevada
| | - Brett Seymoure
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Yantao Shen
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, Nevada
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, Nevada
| | - Jenny Q Ouyang
- Department of Biology, University of Nevada, Reno, Nevada
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Shift-work: is time of eating determining metabolic health? Evidence from animal models. Proc Nutr Soc 2018; 77:199-215. [DOI: 10.1017/s0029665117004128] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The circadian disruption in shift-workers is suggested to be a risk factor to develop overweight and metabolic dysfunction. The conflicting time signals given by shifted activity, shifted food intake and exposure to light at night occurring in the shift-worker are proposed to be the cause for the loss of internal synchrony and the consequent adverse effects on body weight and metabolism. Because food elicited signals have proven to be potent entraining signals for peripheral oscillations, here we review the findings from experimental models of shift-work and verify whether they provide evidence about the causal association between shifted feeding schedules, circadian disruption and altered metabolism. We found mainly four experimental models that mimic the conditions of shift-work: protocols of forced sleep deprivation, of forced activity during the normal rest phase, exposure to light at night and shifted food timing. A big variability in the intensity and duration of the protocols was observed, which led to a diversity of effects. A common result was the disruption of temporal patterns of activity; however, not all studies explored the temporal patterns of food intake. According to studies that evaluate time of food intake as an experimental model of shift-work and studies that evaluate shifted food consumption, time of food intake may be a determining factor for the loss of balance at the circadian and metabolic level.
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Adams CD, Jordahl KM, Copeland W, Mirick DK, Song X, Sather CL, Kelsey K, Houseman A, Davis S, Randolph T, Bhatti P. Nightshift work, chronotype, and genome-wide DNA methylation in blood. Epigenetics 2017; 12:833-840. [PMID: 28837395 DOI: 10.1080/15592294.2017.1366407] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Molecular mechanisms underlying the negative health effects of shift work are poorly understood, which remains a barrier to developing intervention strategies to protect the long-term health of shift workers. We evaluated genome-wide differences in DNA methylation (measured in blood) between 111 actively employed female nightshift and 86 actively employed female dayshift workers from the Seattle metropolitan area. We also explored the effect of chronotype (i.e., measure of preference for activity earlier or later in the day) on DNA methylation among 110 of the female nightshift workers and an additional group of 131 male nightshift workers. Methylation data were generated using the Illumina Infinium HumanMethylation450 BeadChip (450K) Array. After applying the latest methylation data processing methods, we compared methylation levels at 361,210 CpG loci between the groups using linear regression models adjusted for potential confounders and applied the false-discovery rate (FDR) ≤ 0.05 to account for multiple comparisons. No statistically significant associations at the genome-wide level were observed with shift work or chronotype, though based on raw P values and absolute effect sizes, there were suggestive associations in genes that have been previously linked with cancer (e.g., BACH2, JRK, RPS6KA2) and type-2 diabetes (e.g., KCNQ1). Given that our study was underpowered to detect moderate effects, examining these suggestive results in well-powered independent studies or in pooled data sets may improve our understanding of the pathways underlying the negative health effects of shift work and the influence of personal factors such as chronotype. Such an approach may help identify potential interventions that can be used to protect the long-term health of shift workers.
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Affiliation(s)
- Charleen D Adams
- a MRC Integrative Epidemiology Unit, School of Social and Community Medicine, University of Bristol , Bristol , UK.,b Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Kristina M Jordahl
- b Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Wade Copeland
- c Program in Biostatistics, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Dana K Mirick
- b Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Xiaoling Song
- d Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Cassandra L Sather
- e Genomics Resource, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Karl Kelsey
- f Department of Community Health , Brown University , Providence , RI , USA
| | - Andres Houseman
- g College of Public Health and Human Sciences, Oregon State University , Corvallis , OR , USA
| | - Scott Davis
- b Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Timothy Randolph
- c Program in Biostatistics, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
| | - Parveen Bhatti
- b Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center , Seattle , WA , USA
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Hedström AK, Åkerstedt T, Klareskog L, Alfredsson L. Relationship between shift work and the onset of rheumatoid arthritis. RMD Open 2017; 3:e000475. [PMID: 29225920 PMCID: PMC5706490 DOI: 10.1136/rmdopen-2017-000475] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/28/2017] [Accepted: 07/04/2017] [Indexed: 01/26/2023] Open
Abstract
Background Environmental factors play a prominent role in rheumatoid arthritis (RA) aetiology. Shift work has previously been associated with increased RA risk in females. The aim of this study was to investigate the potential association, including a dose–response association, between permanent night shift work, rotating shift work and day-oriented shift work and risk of developing anticitrullinated peptide antibodies (ACPA)-positive and ACPA-negative RA. Methods The present report is based on a population-based, case–control study with incident cases of RA (1951 cases and 2225 controls matched by age, gender and residential area). Using logistic regression, occurrence of RA among subjects who have been exposed to different kinds of shift work was compared with that among those who have never been exposed by calculating the OR with a 95% CI. Results Rotating shift work and day-oriented shift work increased the risk of developing ACPA-positive RA (OR 1.3, 95% CI 1.0 to 1.7 and OR 1.3, 95% CI 1.0 to 1.6), but not ACPA-negative RA. Permanent night shift work appeared to be a protective factor both against ACPA-positive RA (OR 0.7, 95% CI 0.6 to 0.9) and ACPA-negative RA (OR 0.8, 95% CI 0.6 to 1.0). For both subsets of RA, significant trends showed a lower risk of developing RA with increasing duration of permanent night shift work (p value for trend 0.002 vs 0.04). Conclusions Sleep restriction as a consequence of shift work is associated with several biological effects among which changes in melatonin production may be involved. The present epidemiological findings of a complex relationship between sleep patterns and different forms of RA may be of importance for increasing the understanding of the pathophysiology of RA.
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Affiliation(s)
- Anna Karin Hedström
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Torbjörn Åkerstedt
- Stress Research, Stockholm University, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Lars Klareskog
- Rheumatology Unit, Department of Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Lars Alfredsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Daugaard S, Garde AH, Bonde JPE, Christoffersen J, Hansen ÄM, Markvart J, Schlünssen V, Skene DJ, Vistisen HT, Kolstad HA. Night work, light exposure and melatonin on work days and days off. Chronobiol Int 2017; 34:942-955. [DOI: 10.1080/07420528.2017.1327867] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Stine Daugaard
- Aarhus University Hospital, Department of Occupational Medicine, Aarhus, Denmark
| | - Anne Helene Garde
- National Research Centre for the Working Environment, Copenhagen, Denmark
- University of Copenhagen, Institute of Public Health, Copenhagen, Denmark
| | - Jens Peter Ellekilde Bonde
- Bispebjerg Hospital, Department of Occupational Medicine, Copenhagen, Denmark
- University of Copenhagen, Institute of Public Health, Copenhagen, Denmark
| | - Jens Christoffersen
- Velux Danmark A/S, Stakeholder Communications and Sustanability, Horsholm, Denmark
| | - Äse Marie Hansen
- National Research Centre for the Working Environment, Copenhagen, Denmark
- University of Copenhagen, Institute of Public Health, Copenhagen, Denmark
| | - Jakob Markvart
- Aalborg Universitet, Department of Energy Performance, Indoor Environment and Sustainability, Danish Building Research Institute, Copenhagen, Denmark
| | - Vivi Schlünssen
- National Research Centre for the Working Environment, Copenhagen, Denmark
- Aarhus Universitet, Department of Public Health, Aarhus, Denmark
| | - Debra J. Skene
- University of Surrey, Faculty of Health and Medical Sciences, Chronobiology, Guildford GU2 7XH, Surrey, United Kingdom
| | - Helene Tilma Vistisen
- Aarhus University Hospital, Department of Occupational Medicine, Aarhus, Denmark
- Aarhus University Hospital, Aarhus, Denmark
| | - Henrik A. Kolstad
- Aarhus University Hospital, Department of Occupational Medicine, Aarhus, Denmark
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Carson IN, Batson MJ, Tranmer JE, Scribbans TD, Gurd BJ, Pyke KE. Cardiovascular and Cortisol Reactivity to Acute Mental Stress in Female Shift and Non-Shift Workers. SAGE Open Nurs 2017. [DOI: 10.1177/2377960817709181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Ira N. Carson
- School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada
| | | | | | - Trisha D. Scribbans
- School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada
| | - Brendon J. Gurd
- School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada
| | - Kyra E. Pyke
- School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada
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Eynan M, Biram A, Mullokandov M, Kronfeld-Schor N, Paz-Cohen R, Menajem D, Arieli Y. The transition from day-to-night activity is a risk factor for the development of CNS oxygen toxicity in the diurnal fat sand rat (Psammomys obesus). Chronobiol Int 2017; 34:578-586. [PMID: 28156158 DOI: 10.1080/07420528.2017.1281822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Performance and safety are impaired in employees engaged in shift work. Combat divers who use closed-circuit oxygen diving apparatus undergo part of their training during the night hours. The greatest risk involved in diving with such apparatus is the development of central nervous system oxygen toxicity (CNS-OT). We investigated whether the switch from day-to-night activity may be a risk factor for the development of CNS-OT using a diurnal animal model, the fat sand rat (Psammomys obesus). Animals were kept on a 12:12 light-dark schedule (6 a.m. to 6 p.m. at 500 lx). The study included two groups: (1) Control group: animals were kept awake and active during the day, between 09:00 and 15:00. (2) Experimental group: animals were kept awake and active during the night, between 21:00 and 03:00, when they were exposed to dim light in order to simulate the conditions prevalent during combat diver training. This continued for a period of 3 weeks, 5 days a week. On completion of this phase, 6-sulphatoxymelatonin (6-SMT) levels in urine were determined over a period of 24 h. Animals were then exposed to hyperbaric oxygen (HBO). To investigate the effect of acute melatonin administration, melatonin (50 mg/kg) or its vehicle was administered to the animals in both groups 20 min prior to HBO exposure. After the exposure, the activity of superoxide dismutase, catalase and glutathione peroxidase was measured, as were the levels of neuronal nitric oxide synthase (nNOS) and overall nitrotyrosylation in the cortex and hippocampus. Latency to CNS-OT was significantly reduced after the transition from day-to-night activity. This was associated with alterations in the level of melatonin metabolites secreted in the urine. Acute melatonin administration had no effect on latency to CNS-OT in either of the groups. Nevertheless, the activity of superoxide dismutase and catalase, as well as nitrotyrosine and nNOS levels, were altered in the hippocampus following melatonin administration. On the basis of these results, we suggest that a switch from diurnal to nocturnal activity may represent an additional risk factor for the development of CNS-OT. Utilizing a diurnal animal model may contribute to our understanding of the heightened risk of developing CNS-OT when diving with closed-circuit oxygen apparatus at night.
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Affiliation(s)
- Mirit Eynan
- a Israel Naval Medical Institute , IDF Medical Corps , Haifa , Israel
| | - Adi Biram
- a Israel Naval Medical Institute , IDF Medical Corps , Haifa , Israel
| | | | | | - Rotem Paz-Cohen
- b Department of Zoology , Tel Aviv University , Tel Aviv , Israel
| | - Dvir Menajem
- a Israel Naval Medical Institute , IDF Medical Corps , Haifa , Israel
| | - Yehuda Arieli
- a Israel Naval Medical Institute , IDF Medical Corps , Haifa , Israel
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40
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Pastuszak AW, Moon YM, Scovell J, Badal J, Lamb DJ, Link RE, Lipshultz LI. Poor Sleep Quality Predicts Hypogonadal Symptoms and Sexual Dysfunction in Male Nonstandard Shift Workers. Urology 2016; 102:121-125. [PMID: 27988267 DOI: 10.1016/j.urology.2016.11.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 10/26/2016] [Accepted: 11/19/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate the impact of sleep quality in hypogonadal symptoms and sexual function in men working nonstandard shifts. MATERIALS AND METHODS Men treated at a single andrology clinic between July and October 2014 completed questionnaires assessing sleep quality, hypogonadal symptoms (Androgen Deficiency in the Aging Male [ADAM/qADAM]), and sexual function (International Index of Erectile Function [IIEF]). Serum hormone levels were assessed at the time of survey completion. RESULTS One hundred eighty-two men were identified as working nonstandard shifts (work that starts before 7 a.m. or after 2 p.m., rotates, or regularly includes hours outside of the standard 7 a.m. to 6 p.m. workday) with a mean ± SD age of 41.1 ± 10.8 years. Of men working nonstandard shifts, those with better sleep quality had fewer hypogonadal symptoms and better sexual function. Multivariate regression analysis revealed significant linear associations between sleep quality and qADAM score (P = .008), positive ADAM responses (P = .003), and IIEF score (P = .0004). When comparing individual groups, men who were "very satisfied" (n = 60) with sleep quality had higher qADAM scores than men who were "somewhat dissatisfied" (P = .02), and men who were "very dissatisfied" had significantly lower IIEF scores than men who were "very satisfied" (P = .001) and "somewhat satisfied" (P = .005). No associations between sleep quality and mean serum testosterone, free testosterone, estrogen, dehydroepiandrosterone, follicle-stimulating hormone, and luteinizing hormone levels were observed. CONCLUSION Men who work nonstandard shifts and have poor sleep quality are at increased risk for hypogonadal symptoms and sexual dysfunction.
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Affiliation(s)
- Alexander W Pastuszak
- Scott Department of Urology, Baylor College of Medicine, Houston, TX; Division of Male Reproductive Medicine and Surgery, Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX.
| | | | - Jason Scovell
- Scott Department of Urology, Baylor College of Medicine, Houston, TX; Division of Male Reproductive Medicine and Surgery, Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX
| | | | - Dolores J Lamb
- Scott Department of Urology, Baylor College of Medicine, Houston, TX; Division of Male Reproductive Medicine and Surgery, Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX; Department of Cell and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Richard E Link
- Scott Department of Urology, Baylor College of Medicine, Houston, TX
| | - Larry I Lipshultz
- Scott Department of Urology, Baylor College of Medicine, Houston, TX; Division of Male Reproductive Medicine and Surgery, Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX
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Massey AJ, Campbell BK, Raine-Fenning N, Pincott-Allen C, Perry J, Vedhara K. Relationship between hair and salivary cortisol and pregnancy in women undergoing IVF. Psychoneuroendocrinology 2016; 74:397-405. [PMID: 27756033 DOI: 10.1016/j.psyneuen.2016.08.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/09/2016] [Accepted: 08/30/2016] [Indexed: 11/16/2022]
Abstract
Evidence for an association between cortisol and clinical pregnancy in women undergoing In Vitro Fertilisation (IVF) is mixed with previous studies relying exclusively on short term measures of cortisol in blood, saliva, urine, and/or follicular fluid. Hair sampling allows analysis of systemic levels of cortisol over the preceding 3-6 months. The present study sought to explore the relationship between cortisol and clinical pregnancy outcome in women undergoing IVF utilising multiple indices of cortisol derived from both saliva and hair measured prior to commencing gonadotrophin treatment. A total of 135 women (mean age 34.5 SD+/-4.8) were recruited from an English fertility clinic (December 2012-April 2014) 60% of whom became pregnant (n=81). Salivary cortisol data were obtained over two days: upon awakening, 30min post awakening, and at 22:00. A subsample (n=88) of the women providing salivary samples were approached consecutively to provide hair samples for the measurement of cortisol. Independent Logistic regression analyses revealed that salivary cortisol measures including cortisol awakening response (CAR) (p=0.485), area under the curve with respect to ground (AUCg) (p=0.527), area under the curve with respect to increase (AUCi) (p=0.731) and diurnal slope (p=0.889) did not predict clinical pregnancy. In contrast, hair cortisol concentrations significantly predicted clinical pregnancy (p=0.017). Associations between hair cortisol and clinical pregnancy remained when controlling for accumulations of salivary cortisol (p=0.034) accounting for 26.7% of the variance in pregnancy outcome. These findings provide preliminary evidence that longer term systemic cortisol may influence reproductive outcomes; and in turn suggests that interventions to reduce cortisol prior to commencing IVF could improve treatment outcomes.
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Affiliation(s)
- Adam J Massey
- Division of Primary Care, School of Medicine, University of Nottingham, UK.
| | - Bruce K Campbell
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, UK.
| | - Nick Raine-Fenning
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, UK; Nurture Fertility, UK.
| | - Catherine Pincott-Allen
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, UK.
| | - Jane Perry
- Division of Primary Care, School of Medicine, University of Nottingham, UK.
| | - Kavita Vedhara
- Division of Primary Care, School of Medicine, University of Nottingham, UK.
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42
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Devore EE, Harrison SL, Stone KL, Holton KF, Barrett-Connor E, Ancoli-Israel S, Yaffe K, Ensrud K, Cawthon PM, Redline S, Orwoll E, Schernhammer ES. Association of urinary melatonin levels and aging-related outcomes in older men. Sleep Med 2016; 23:73-80. [PMID: 27692280 DOI: 10.1016/j.sleep.2016.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/12/2016] [Accepted: 07/20/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Circadian disruptions can contribute to accelerated aging, and the circadian system regulates cognitive and physical functions; therefore, circadian markers (eg, melatonin) may be associated with key aspects of healthy aging and longevity. OBJECTIVE To evaluate urinary melatonin levels in relation to cognitive function, physical function, and mortality among 2,821 older men in the Osteoporotic Fractures in Men Study DESIGN: Cohort study. MEASUREMENTS In 2003-2005, participants provided first-morning spot urine samples, which were assayed for 6-sulfatoxymelatonin (the primary melatonin metabolite in urine); cognitive and physical function assessments were completed twice, at baseline and an average of 6.5 years later. Participant deaths were confirmed by central review of death certificates over a mean of 9.2 years of follow up. RESULTS In multivariable-adjusted regression models, we observed a significant trend of better Digit Vigilance Test scores (ie, decreased time to completion) at baseline across increasing melatonin quartiles (p-trend = 0.01); however, mean time-to-completion scores did not significantly differ comparing extreme quartiles (group means: 547.1 seconds (95% CI: 533.6, 560.6) versus 561.3 seconds (95% CI: 547.8, 574.9)), and there were no associations of urinary melatonin levels with other cognitive test scores, or any cognitive change scores over time. Furthermore, melatonin levels were not related to physical function scores (p-trends = 0.4 for walking speed, 0.7 for chair stands, and 0.6 for grip strength in fully-adjusted models) or mortality risk (p-trend = 0.3 in the fully-adjusted model). CONCLUSION We found little evidence of associations between urinary melatonin levels and key measures of healthy aging and mortality in this cohort of older men. Further research should explore the relation of melatonin, particularly if assessed earlier in life, and other circadian markers with healthy aging outcomes.
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Affiliation(s)
- Elizabeth E Devore
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, USA.
| | | | - Katie L Stone
- California Pacific Medical Center Research Institute, USA
| | - Kathleen F Holton
- Department of Health Studies, Center for Behavioral Neuroscience, American University, USA
| | - Elizabeth Barrett-Connor
- Division of Epidemiology, Department of Family Medicine and Public Health, University of California San Diego, USA
| | - Sonia Ancoli-Israel
- Department of Psychiatry, University of California San Diego, USA; Department of Medicine, University of California San Diego, USA
| | - Kristine Yaffe
- Department of Psychiatry, University of California San Francisco, USA; Department of Neurology, University of California San Francisco, USA; Department of Epidemiology, University of California San Francisco, USA
| | - Kristine Ensrud
- Center for Chronic Disease Outcomes Research, Minneapolis VA Health Care System, USA; Department of Medicine, University of Minnesota, USA; Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, USA
| | - Peggy M Cawthon
- California Pacific Medical Center Research Institute, USA; Department of Epidemiology and Biostatistics, University of California San Francisco, USA
| | - Susan Redline
- Departments of Medicine, Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, and Harvard Medical School, USA
| | - Eric Orwoll
- Oregon Clinical and Translational Research Institute and School of Medicine, Oregon Health and Science University, USA
| | - Eva S Schernhammer
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, USA; Department of Epidemiology, H.T. Chan Harvard School of Public Health, USA; Department of Epidemiology, Center for Public Health, Medical University of Vienna, Austria
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43
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Zeman M, Molcan L, Herichova I, Okuliarova M. Endocrine and cardiovascular rhythms differentially adapt to chronic phase-delay shifts in rats. Chronobiol Int 2016; 33:1148-1160. [PMID: 27459109 DOI: 10.1080/07420528.2016.1203332] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Disturbances in regular circadian oscillations can have negative effects on cardiovascular function, but epidemiological data are inconclusive and new data from animal experiments elucidating critical biological mechanisms are needed. To evaluate the consequences of chronic phase shifts of the light/dark (LD) cycle on hormonal and cardiovascular rhythms, two experiments were performed. In Experiment 1, male rats were exposed to either a regular 12:12 LD cycle (CONT) or rotating 8-h phase-delay shifts of LD every second day (SHIFT) for 10 weeks. During this period, blood pressure (BP) was monitored weekly, and daily rhythms of melatonin, corticosterone, leptin and testosterone were evaluated at the end of the experiment. In Experiment 2, female rats were exposed to the identical shifted LD schedule for 12 weeks, and daily rhythms of BP, heart rate (HR) and locomotor activity were recorded using telemetry. Preserved melatonin rhythms were found in the pineal gland, plasma, heart and kidney of SHIFT rats with damped amplitude in the plasma and heart, suggesting that the central oscillator can adapt to chronic phase-delay shifts. In contrast, daily rhythms of corticosterone, testosterone and leptin were eliminated in SHIFT rats. Exposure to phase shifts did not lead to increased body weight and elevated BP. However, a shifted LD schedule substantially decreased the amplitude and suppressed the circadian power of the daily rhythms of BP and HR, implying weakened circadian control of physiological and behavioural processes. The results demonstrate that endocrine and cardiovascular rhythms can differentially adapt to chronic phase-delay shifts, promoting internal desynchronization between central and peripheral oscillators, which in combination with other negative environmental stimuli may result in negative health effects.
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Affiliation(s)
- Michal Zeman
- a Department of Animal Physiology and Ethology, Faculty of Natural Sciences , Comenius University , Bratislava , Slovak Republic
| | - Lubos Molcan
- a Department of Animal Physiology and Ethology, Faculty of Natural Sciences , Comenius University , Bratislava , Slovak Republic
| | - Iveta Herichova
- a Department of Animal Physiology and Ethology, Faculty of Natural Sciences , Comenius University , Bratislava , Slovak Republic
| | - Monika Okuliarova
- a Department of Animal Physiology and Ethology, Faculty of Natural Sciences , Comenius University , Bratislava , Slovak Republic
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Tai SY, Huang SP, Bao BY, Wu MT. Urinary melatonin-sulfate/cortisol ratio and the presence of prostate cancer: A case-control study. Sci Rep 2016; 6:29606. [PMID: 27387675 PMCID: PMC4937372 DOI: 10.1038/srep29606] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/22/2016] [Indexed: 12/29/2022] Open
Abstract
The circadian-related hormones, melatonin and cortisol, have oncostatic and immunosuppressive properties. This study examined the relationship between these two biomarkers and the presence of prostate cancer. We measured their major metabolites in urine collected from 120 newly diagnosed prostate cancer patients and 240 age-matched controls from January 2011 to April 2014. Compared with patients with lower urinary melatonin-sulfate or melatonin-sulfate/cortisol (MT/C) ratio levels, those with above-median levels were significantly less likely to have prostate cancer (adjusted OR (aOR) = 0.59, 95% CI = 0.35–0.99; aOR = 0.46, 95% CI: 0.27–0.77) or advanced stage prostate cancer (aOR = 0.49, 95% CI = 0.26–0.89; aOR = 0.33, 95% CI = 0.17–0.62). The combined effect of both low MT/C ratios and PSA levels exceeding 10 ng/ml was an 8.82-fold greater likelihood of prostate cancer and a 32.06-fold greater likelihood of advanced stage prostate cancer, compared to those with both high MT/C ratios and PSA levels less than 10 ng/ml. In conclusion, patients with high melatonin-sulfate levels or a high MT/C ratio were less likely to have prostate cancer or advanced stage prostate. Besides, a finding of a low MT/C ratio combined with a PSA level exceeding 10 ng/ml showed the greatest potential in detecting prostate cancer and advanced stage prostate cancer.
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Affiliation(s)
- Shu-Yu Tai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Family Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Family Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan.,Department of Family Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shu-Pin Huang
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Bo-Ying Bao
- Department of Pharmacy, China Medical University, Taichung, Taiwan.,Sex Hormone Research Center, China Medical University Hospital, Taichung, Taiwan.,Department of Nursing, Asia University, Taichung, Taiwan
| | - Ming-Tsang Wu
- Department of Family Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Public Health, Kaohsiung Medical University, Kaohsiung Medical University, Kaohsiung, Taiwan.,Center of Environmental and Occupational Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
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45
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Song G, Yoon KA, Chi H, Roh J, Kim JH. Decreased concentration of serum melatonin in nighttime compared with daytime female medical technologists in South Korea. Chronobiol Int 2016; 33:1305-1310. [PMID: 27385051 DOI: 10.1080/07420528.2016.1199562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Working during the night can disrupt the normal circadian rhythm by altering the melatonin level. A low level of melatonin is associated with an increased risk of cancer, possibly by decreasing the expression of tumor-suppressor genes, such as p53. To determine whether nighttime work is associated with melatonin level in serum as well as the expression of related genetic markers, we enrolled 100 female nighttime medical technologists employed at a hospital in South Korea. Melatonin concentration and melatonin receptor 1 (MT1) expression were significantly lower in nighttime than in daytime workers (1.84 pg/mL versus 4.04 pg/mL; 1.16 versus 1.61, respectively). However, p53 expression showed no difference between the groups. In summary, nighttime work could be an important risk factor for circadian disruption, but not a direct risk factor for cancer in medical technologists in South Korea.
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Affiliation(s)
- GiSeon Song
- a Seegene Medical Foundation , Seoul , Korea.,c Samkwang Medical Laboratories , Seoul , Korea
| | - Kyong-Ah Yoon
- b College of Veterinary Medicine, Konkuk University , Seoul , Korea
| | | | - Jaehoon Roh
- d The Institute for Occupational Health , Department of Preventive Medicine and Public Health , Seoul , Korea.,e The Institute for Occupational Health , Yonsei University College of Medicine , Seoul , Korea.,f Graduate School of Public Health , Yonsei University College of Medicine , Seoul , Korea
| | - Jin-Hee Kim
- g Department of Biomedical Laboratory Science, College of Health Science , Cheongju University , Cheongju , Korea
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46
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Bhatti P, Mirick DK, Randolph TW, Gong J, Buchanan DT, Zhang J(J, Davis S. Oxidative DNA damage during sleep periods among nightshift workers. Occup Environ Med 2016; 73:537-44. [DOI: 10.1136/oemed-2016-103629] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/25/2016] [Indexed: 01/15/2023]
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48
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Lin Y, Nishiyama T, Kurosawa M, Tamakoshi A, Kubo T, Fujino Y, Kikuchi S. Association between shift work and the risk of death from biliary tract cancer in Japanese men. BMC Cancer 2015; 15:757. [PMID: 26490349 PMCID: PMC4618019 DOI: 10.1186/s12885-015-1722-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 10/08/2015] [Indexed: 12/14/2022] Open
Abstract
Background There is increasing evidence suggesting that shift work involving night work may increase cancer risk. Methods We examined the association between working rotating shifts and the risk of death from biliary tract cancer among Japanese men who participated in the Japan Collaborative Cohort Study. Of the 46,395 men recruited, 22,224 men aged 40–65 at baseline (1988–1990) who reported working full-time or were self-employed were included in the present analysis. The study subjects were followed through December 31, 2009. Information regarding occupation and lifestyle factors was collected using a self-administered questionnaire. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95 % confidence interval (CI) for the risk of death from biliary tract cancer in relation to shift work. Results During a mean 17-year follow-up, we observed 94 biliary tract cancer deaths, including 23 deaths from gallbladder cancer and 71 deaths from extrahepatic bile duct cancer. Overall, shift work was associated with a statistically non-significant increase in the risk of biliary tract cancer, with an HR of 1.50 (95 % CI: 0.81-2.77), among rotating shift workers. When the analysis was limited to extrahepatic bile duct cancer, a significant association appeared, with a multivariable-adjusted HR of 1.93 (95 % CI: 1.00-3.72) for rotating shift workers. Conclusion Our data indicate that shift work may be associated with increased risk of death from extrahepatic bile duct cancer in this cohort of Japanese men. The association with gallbladder cancer remains unclear because of the small number of deaths.
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Affiliation(s)
- Yingsong Lin
- Department of Public Health, Aichi Medical University School of Medicine, 1-1 Yazakokarimata, Nagakute, Aichi, 4980-1195, Japan.
| | - Takeshi Nishiyama
- Department of Public Health, Aichi Medical University School of Medicine, 1-1 Yazakokarimata, Nagakute, Aichi, 4980-1195, Japan.
| | - Michiko Kurosawa
- Department of Epidemiology and Environmental Medicine, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Akiko Tamakoshi
- Department of Public Health, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
| | - Tatsuhiko Kubo
- Department of Preventive Medicine and Community Health, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahata-nishi-ku, 807-8555, Kitakyushu, Japan.
| | - Yoshihisa Fujino
- Department of Preventive Medicine and Community Health, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahata-nishi-ku, 807-8555, Kitakyushu, Japan.
| | - Shogo Kikuchi
- Department of Public Health, Aichi Medical University School of Medicine, 1-1 Yazakokarimata, Nagakute, Aichi, 4980-1195, Japan.
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Tan DX, Manchester LC, Esteban-Zubero E, Zhou Z, Reiter RJ. Melatonin as a Potent and Inducible Endogenous Antioxidant: Synthesis and Metabolism. Molecules 2015; 20:18886-906. [PMID: 26501252 PMCID: PMC6332205 DOI: 10.3390/molecules201018886] [Citation(s) in RCA: 373] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 11/17/2022] Open
Abstract
Melatonin is a tryptophan-derived molecule with pleiotropic activities. It is present in almost all or all organisms. Its synthetic pathway depends on the species in which it is measured. For example, the tryptophan to melatonin pathway differs in plants and animals. It is speculated that the melatonin synthetic machinery in eukaryotes was inherited from bacteria as a result of endosymbiosis. However, melatonin's synthetic mechanisms in microorganisms are currently unknown. Melatonin metabolism is highly complex with these enzymatic processes having evolved from cytochrome C. In addition to its enzymatic degradation, melatonin is metabolized via pseudoenzymatic and free radical interactive processes. The metabolic products of these processes overlap and it is often difficult to determine which process is dominant. However, under oxidative stress, the free radical interactive pathway may be featured over the others. Because of the complexity of the melatonin degradative processes, it is expected that additional novel melatonin metabolites will be identified in future investigations. The original and primary function of melatonin in early life forms such as in unicellular organisms was as a free radical scavenger and antioxidant. During evolution, melatonin was selected as a signaling molecule to transduce the environmental photoperiodic information into an endocrine message in multicellular organisms and for other purposes as well. As an antioxidant, melatonin exhibits several unique features which differ from the classic antioxidants. These include its cascade reaction with free radicals and its capacity to be induced under moderate oxidative stress. These features make melatonin a potent endogenously-occurring antioxidant that protects organisms from catastrophic oxidative stress.
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Affiliation(s)
- Dun-Xian Tan
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Lucien C Manchester
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Eduardo Esteban-Zubero
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Zhou Zhou
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
| | - Russel J Reiter
- Department of Cellular and Structural Biology, Health Science Center, University of Texas, San Antonio, TX 78229, USA.
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Sleep interruption associated with house staff work schedules alters circadian gene expression. Sleep Med 2015; 16:1388-1394. [PMID: 26498241 DOI: 10.1016/j.sleep.2015.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/15/2015] [Accepted: 06/06/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND Epidemiological studies indicate that disruption of circadian rhythm by shift work increases the risk of breast and prostate cancer. Our studies demonstrated that carcinogens disrupt the circadian expression of circadian genes (CGs) and circadian-controlled genes (CCGs) during the early stages of rat mammary carcinogenesis. A chemopreventive regimen of methylselenocysteine (MSC) restored the circadian expression of CGs and CCGs, including PERIOD 2 (PER2) and estrogen receptor β (ERS2), to normal. The present study evaluated whether changes in CG and CCG expression in whole blood can serve as indicators of circadian disruption in shift workers. METHODS Fifteen shift workers were recruited to a crossover study. Blood samples were drawn before (6 PM) and after (8 AM) completing a night shift after at least seven days on floating night-shift rotation, and before (8 AM), during (1 PM), and after (6 PM) completing seven days on day shift. The plasma melatonin level and messenger RNA (mRNA) expression of PER2, nuclear receptor subfamily 1, group d, member 1 (NR1D1), and ERS2 were measured, and the changes in levels of melatonin and gene expression were evaluated with statistical analyses. RESULTS The mRNA expression of PER2 was affected by shift (p = 0.0079); the levels were higher in the evening for the night shift, but higher in the morning for the day shift. Increased PER2 expression (p = 0.034) was observed in the evening on the night versus day shifts. The melatonin level was higher in the morning for both day shifts (p = 0.013) and night shifts (p <0.0001). CONCLUSION Changes in the level of PER2 gene expression can serve as a biomarker of disrupted circadian rhythm in blood cells. Therefore, they can be a useful intermediate indicator of efficacy in future MSC-mediated chemoprevention studies.
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