scholarly journals Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature

2017 ◽  
Vol 19 (4) ◽  
pp. 365-374 ◽  
Author(s):  
Claudia M. Hunter ◽  
Mariana G. Figueiro
Keyword(s):  
Shift Work ◽  
Quantitative Methods ◽  
English Language ◽  
Circadian Disruption ◽  
Light At Night ◽  
Shift Workers ◽  
Pubmed Database ◽  
Increased Risk ◽  
Disease Risks ◽  
Cancerous Cells

Shift work, especially that involving rotating and night shifts, is associated with an increased risk of diseases, including cancer. Attempts to explain the association between shift work and cancer in particular have focused on the processes of melatonin production and suppression. One hypothesis postulates that exposure to light at night (LAN) suppresses melatonin, whose production is known to slow the development of cancerous cells, while another proposes that circadian disruption associated with shift work, and not just LAN, increases health risks. This review focuses on six studies that employed quantitative measurement of LAN and melatonin levels to assess cancer risks in shift workers. These studies were identified via searching the PubMed database for peer-reviewed, English-language articles examining the links between shift work, LAN, and disease using the terms light at night, circadian disruption, health, risk, cancer, shift work, or rotating shift. While the results indicate a growing consensus on the relationship between disease risks (particularly cancer) and circadian disruption associated with shift work, the establishment of a direct link between LAN and disease has been impeded by contradictory studies and a lack of consistent, quantitative methods for measuring LAN in the research to date. Better protocols for assessing personal LAN exposure are required, particularly those employing calibrated devices that measure and sample exposure to workplace light conditions, to accurately assess LAN’s effects on the circadian system and disease. Other methodologies, such as measuring circadian disruption and melatonin levels in the field, may also help to resolve discrepancies in the findings.

scholarly journals Shift-work: is time of eating determining metabolic health? Evidence from animal models

2018 ◽  
Vol 77 (3) ◽  
pp. 199-215 ◽  
Author(s):  
Natalí N. Guerrero-Vargas ◽  
Estefania Espitia-Bautista ◽  
Ruud M. Buijs ◽  
Carolina Escobar
Keyword(s):  
Food Intake ◽  
Shift Work ◽  
Temporal Patterns ◽  
Experimental Models ◽  
Circadian Disruption ◽  
Metabolic Dysfunction ◽  
Light At Night ◽  
Shift Workers ◽  
Time Signals ◽  
Altered Metabolism

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.

MP91-06 INCREASED RISK OF HYPOGONADAL SYMPTOMS IN SHIFT WORKERS WITH SHIFT WORK SLEEP DISORDER

2017 ◽  
Vol 197 (4S) ◽  
Author(s):  
Will Kirby ◽  
Adithya Balasubramanian ◽  
Javier Santiago ◽  
Mark Hockenberry ◽  
David Skutt ◽  
...  
Keyword(s):  
Sleep Disorder ◽  
Shift Work ◽  
Shift Workers ◽  
Shift Work Sleep Disorder ◽  
Increased Risk

scholarly journals Shift Work and Breast Cancer

2020 ◽  
Vol 17 (24) ◽  
pp. 9544
Author(s):  
Sarah Gehlert ◽  
Mark Clanton ◽  
Keyword(s):  
Breast Cancer ◽  
Shift Work ◽  
Causal Link ◽  
Sleep Cycle ◽  
Light At Night ◽  
Future Directions ◽  
Increased Risk ◽  
Part Time ◽  
Rotating Shift Work ◽  
Normal Sleep

The rates of shift work outside of daylight hours have increased in recent years, and nighttime shift work is now considered a potential carcinogenic occupational exposure. Light at night exposure, lower melatonin production, and the production of stress-related mediators disrupt normal sleep–wake cycles. Women who work lower-wage jobs and part-time workers whose shifts are determined entirely by their supervisors (rotating shifts) may be subject to stress related to efforts to align childcare and other needs with the unpredictable nature of rotating shift work. The causal link between breast cancer and the sleep cycle or circadian disruption are yet to be established; however, disruption of the circadian cycles by light at night exposure or chronic exposure to stress-related mediators have all been linked to the increased risk of breast cancer. We review the existing literature on shift work and breast cancer, identify knowledge gaps, and suggest future directions for research.

scholarly journals Circadian misalignment increases mood vulnerability in simulated shift work

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sarah L. Chellappa ◽  
Christopher J. Morris ◽  
Frank A. J. L. Scheer
Keyword(s):  
Shift Work ◽  
Night Shift ◽  
Well Being ◽  
Continuous Exposure ◽  
Shift Workers ◽  
Circadian Misalignment ◽  
Alignment Condition ◽  
Increased Risk ◽  
Mood Effects ◽  
Alignment Interaction

Abstract Night shift work can associate with an increased risk for depression. As night workers experience a ‘misalignment’ between their circadian system and daily sleep–wake behaviors, with negative health consequences, we investigated whether exposure to circadian misalignment underpins mood vulnerability in simulated shift work. We performed randomized within-subject crossover laboratory studies in non-shift workers and shift workers. Simulated night shifts were used to induce a misalignment between the endogenous circadian pacemaker and sleep/wake cycles (circadian misalignment), while environmental conditions and food intake were controlled. Circadian misalignment adversely impacted emotional state, such that mood and well-being levels were significantly decreased throughout 4 days of continuous exposure to circadian misalignment in non-shift workers, as compared to when they were under circadian alignment (interaction of “circadian alignment condition” vs. “day”, mood: p < 0.001; well-being: p < 0.001; adjusted p-values). Similarly, in shift workers, mood and well-being levels were significantly reduced throughout days of misalignment, as compared to circadian alignment (interaction of “circadian alignment condition” vs. “day”, mood: p = 0.002; well-being: p = 0.002; adjusted p-values). Our findings indicate that circadian misalignment is an important biological component for mood vulnerability, and that individuals who engage in shift work are susceptible to its deleterious mood effects.

scholarly journals Total Antioxidant Capacity and Malondialdehyde in Depressive Rotational Shift Workers

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Farahnaz Khajehnasiri ◽  
Seyed Bagher Mortazavi ◽  
Abdolamir Allameh ◽  
Shahin Akhondzadeh ◽  
Hassan Hashemi
Keyword(s):  
Oxidative Stress ◽  
Standard Deviation ◽  
Antioxidant Capacity ◽  
Shift Work ◽  
Work Experience ◽  
Total Antioxidant Capacity ◽  
Depression Score ◽  
Shift Workers ◽  
Increased Risk ◽  
Total Antioxidant

Shift work is associated with sleep deprivation, occupational stress, and increased risk of depression. Depressed patients show increased oxidative stress. During excessive oxidative stress, Malondialdehyde (MDA) increases and total antioxidant capacity (TAC) decreases in body. This cross-sectional study was conducted to determine the serum level of TAC and MDA among depressed rotational shift workers in Shahid Tondooyan Tehran Oil Refinery. 21-item Beck Depression Inventory was used to measure depression level. The level of TAC and MDA was measured by 8 mL fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the ABTS. Results of this study showed that TAC mean and standard deviation concentration was 2.451 (±0.536) mg/dL and MDA was 3.725 (±1.098) mic·mol/L, and mean and standard deviation of depression score and BMI were 14.07 (±3.84) and 24.92 (±3.65) kg/m2, respectively. Depression score had a positive correlation with rotational shift work experience and work experience (r=0.218andr=0.212), respectively, (P<0.05).

scholarly journals Night shift work is associated with an increased risk of asthma

Thorax ◽  
2020 ◽  
Vol 76 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Robert J Maidstone ◽  
James Turner ◽  
Celine Vetter ◽  
Hassan S Dashti ◽  
Richa Saxena ◽  
...  
Keyword(s):  
Public Health ◽  
Severe Asthma ◽  
Shift Work ◽  
Inflammatory Diseases ◽  
Large Population ◽  
Night Shift ◽  
Smoking History ◽  
Shift Workers ◽  
Increased Risk ◽  
The Impact

IntroductionShift work causes misalignment between internal circadian time and the external light/dark cycle and is associated with metabolic disorders and cancer. Approximately 20% of the working population in industrialised countries work permanent or rotating night shifts, exposing this large population to the risk of circadian misalignment-driven disease. Analysis of the impact of shift work on chronic inflammatory diseases is lacking. We investigated the association between shift work and asthma.MethodsWe describe the cross-sectional relationship between shift work and prevalent asthma in >280000 UK Biobank participants, making adjustments for major confounding factors (smoking history, ethnicity, socioeconomic status, physical activity, body mass index). We also investigated chronotype.ResultsCompared with day workers, ‘permanent’ night shift workers had a higher likelihood of moderate-severe asthma (OR 1.36 (95% CI 1.03 to 1.8)) and all asthma (OR 1.23 (95% CI 1.03 to 1.46)). Individuals doing any type of shift work had higher adjusted odds of wheeze/whistling in the chest. Shift workers who never or rarely worked on nights and people working permanent nights had a higher adjusted likelihood of having reduced lung function (FEV1 <80% predicted). We found an increase in the risk of moderate-severe asthma in morning chronotypes working irregular shifts, including nights (OR 1.55 (95% CI 1.06 to 2.27)).ConclusionsThe public health implications of these findings are far-reaching due to the high prevalence and co-occurrence of both asthma and shift work. Future longitudinal follow-up studies are needed to determine if modifying shift work schedules to take into account chronotype might present a public health measure to reduce the risk of developing inflammatory diseases such as asthma.

Increased Risk of Hypogonadal Symptoms in Shift Workers With Shift Work Sleep Disorder

Urology ◽  
2020 ◽  
Vol 138 ◽  
pp. 52-59 ◽  
Author(s):  
Adithya Balasubramanian ◽  
Taylor P. Kohn ◽  
Javier E. Santiago ◽  
John T. Sigalos ◽  
E. Will Kirby ◽  
...  
Keyword(s):  
Sleep Disorder ◽  
Shift Work ◽  
Shift Workers ◽  
Shift Work Sleep Disorder ◽  
Increased Risk

scholarly journals Body mass index, shift work and food consumption: what relationship?

2021 ◽  
Vol 31 (Supplement_2) ◽  
Author(s):  
Carolina Morgado ◽  
João Lima
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Shift Work ◽  
Online Survey ◽  
Negative Influence ◽  
The Body ◽  
Fruit And Vegetables ◽  
Work Schedule ◽  
Shift Workers ◽  
Increased Risk

Abstract Background A significant percentage of the population is working on shift work and according to several studies this type of work schedule has been associated with an increased risk of developing some pathologies, such as obesity, which are one of the biggest mortality causes in the world. To understand if the shift work has a negative influence on the workers' diet and if it affects the Body Mass Index. Methods Observational and cross-sectional research was conducted, through an online survey designed for this purpose, including fruit and vegetables consumption, sociodemographic characteristics, shift work schedule, sleep hours and reported values of weight and height. The study was ethical approval and statistical analysis was performed using the IBM SPSS Statistics software. A critical significance level of 5% was considered. Results 145 workers were evaluated with an average age of 35.90 ± 10.92 years and an average Body Mass Index of 25.12 ± 4.54 kg/m2, 76.6% were female. 51.7% of the individuals worked on shift work. Body Mass Index of shift workers is higher than Body Mass Index day shift workers (P = 0.001), and they sleep, on average, less hours than day workers. No differences was observed related to fruit and vegetables consumptions. Shift workers reported to have higher difficult to management food intake when compared with day workers (P &lt; 0.001). Conclusions Shift work seems to have a negative influence on the workers' sleep and in Body Mass Index. This study is important to develop, in the future, individualized strategies, for these workers

scholarly journals Relationship Between Shift Work and the Risk of Prostate Cancer: An Evidence Base Case Report

2021 ◽  
Vol 1 (1) ◽  
pp. 23-31
Author(s):  
Irwan Suhadi ◽  
Indah Widyahening ◽  
Muhammad Ilyas
Keyword(s):  
Prostate Cancer ◽  
Shift Work ◽  
Clock Genes ◽  
Evidence Base ◽  
International Agency ◽  
Base Case ◽  
Light At Night ◽  
Increased Risk ◽  
The Relationship ◽  
Manufacture Company

Prostate cancer has been associated with jobs that involve some degree of work at night. In 2007, the International Agency for Research on Cancer (IARC) concluded that shift work involving circadian disruption was probably carcinogenic in humans. Exposure to artificial LAN (Light at Night) suppresses pineal melatonin secretion and subsequently leads to an increase of sex hormones, which in turn could increase the susceptibility to hormone-dependent cancers. Disruption of the circadian rhythm regulated by several clock genes controlling apoptosis and cell proliferation, repeated phase shifting leading to internal desynchronisation and defects in the regulation of the circadian cell cycle, and also sleep deprivation alters immune function. In this case, the authors assessed the relationship between workers in a manufacture company who had worked shift work for 30 years and an increased risk of prostate cancer. This case takes evidence base from several journals that support this hypothesis while doing a critical appraisal to determine its validity and applicability.

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