Prospective Associations Between Working Time Arrangements and Psychiatric Treatment in Denmark: Protocol for a Cohort Study

Background The burden of mental ill health in working-age populations has prompted research on possible links between work-related factors and mental ill health. Long working hours and night shift work are some of the factors that have been studied in relation to the risk of developing mental ill health. Yet, previous studies have not generated conclusive evidence, and further studies of high quality are needed. Objective This study aims to investigate the prospective association between working time arrangements and mental health in terms of psychotropic drug usage or psychiatric hospital treatment in the general working population of Denmark. Methods Data on total weekly working hours in any job and night shift work from the Danish Labor Force Survey 2000–2013 will be linked to data from the Psychiatric Central Research Register (expected 2400 cases during 700,000 person years at risk) and National Prescription Registry (expected 17,400 cases during 600,000 person years at risk). Participants will be followed for up to 5 years. We will use Poisson regression to separately analyze incidence rates of redeemed prescriptions for psychotropic medicine and incidence rates of psychiatric hospital treatment due to mood disorders, anxiety disorders, or stress-related disorders as a function of weekly working hours and night shift work. The analyses will be controlled for sex, age, calendar time of the interview, and socioeconomic status. Results This is a study protocol. Power calculations indicate that the study has sufficient statistical power to detect relatively small differences in risks and minor interactions (eg, ~90% power to detect a rate ratio of 1.1 for psychoactive medication use). We expect the analyses to be completed by the end of 2020 and the results to be published in 2021. Conclusions In this study protocol, all hypotheses and statistical models of the project have been completely defined before we link the exposure data to the outcome data. The results of the project will indicate to what extent and in what direction the national burden of mental ill health in Denmark has been influenced by long working hours and night shift work. International Registered Report Identifier (IRRID) DERR1-10.2196/18236

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Prospective Associations Between Working Time Arrangements and Psychiatric Treatment in Denmark: Protocol for a Cohort Study (Preprint)

10.2196/preprints.18236 ◽

2020 ◽

Author(s):

Harald Hannerz ◽

Karen Albertsen ◽

Martin Lindhardt Nielsen ◽

Anne Helene Garde

Keyword(s):

At Risk ◽

Psychiatric Hospital ◽

Shift Work ◽

Study Protocol ◽

Night Shift ◽

Working Hours ◽

Incidence Rates ◽

Hospital Treatment ◽

Long Working Hours ◽

Night Shift Work

BACKGROUND The burden of mental ill health in working-age populations has prompted research on possible links between work-related factors and mental ill health. Long working hours and night shift work are some of the factors that have been studied in relation to the risk of developing mental ill health. Yet, previous studies have not generated conclusive evidence, and further studies of high quality are needed. OBJECTIVE This study aims to investigate the prospective association between working time arrangements and mental health in terms of psychotropic drug usage or psychiatric hospital treatment in the general working population of Denmark. METHODS Data on total weekly working hours in any job and night shift work from the Danish Labor Force Survey 2000–2013 will be linked to data from the Psychiatric Central Research Register (expected 2400 cases during 700,000 person years at risk) and National Prescription Registry (expected 17,400 cases during 600,000 person years at risk). Participants will be followed for up to 5 years. We will use Poisson regression to separately analyze incidence rates of redeemed prescriptions for psychotropic medicine and incidence rates of psychiatric hospital treatment due to mood disorders, anxiety disorders, or stress-related disorders as a function of weekly working hours and night shift work. The analyses will be controlled for sex, age, calendar time of the interview, and socioeconomic status. RESULTS This is a study protocol. Power calculations indicate that the study has sufficient statistical power to detect relatively small differences in risks and minor interactions (eg, ~90% power to detect a rate ratio of 1.1 for psychoactive medication use). We expect the analyses to be completed by the end of 2020 and the results to be published in 2021. CONCLUSIONS In this study protocol, all hypotheses and statistical models of the project have been completely defined before we link the exposure data to the outcome data. The results of the project will indicate to what extent and in what direction the national burden of mental ill health in Denmark has been influenced by long working hours and night shift work. INTERNATIONAL REGISTERED REPORT DERR1-10.2196/18236

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Association between work schedules and motivation for lifestyle change in workers with overweight or obesity: a cross-sectional study in Japan

BMJ Open ◽

10.1136/bmjopen-2019-033000 ◽

2020 ◽

Vol 10 (4) ◽

pp. e033000

Author(s):

Yukihiro Tanikawa ◽

Miho Kimachi ◽

Minoru Ishikawa ◽

Tomoichiro Hisada ◽

Shunichi Fukuhara ◽

...

Keyword(s):

Shift Work ◽

Subgroup Analysis ◽

Behavioural Change ◽

Night Shift ◽

Working Hours ◽

Cross Sectional ◽

Shift Workers ◽

Long Working Hours ◽

Night Shift Work ◽

Overweight Or Obesity

ObjectiveTo investigate the association between work schedules and motivation for behavioural change of lifestyle, based on the transtheoretical model (TTM) in workers with overweight or obesity.DesignA cross-sectional observational study.SettingA healthcare examination centre in Japan.ParticipantsBetween April 2014 and March 2016, we recruited 9243 participants who underwent healthcare examination and met the inclusion criteria, namely, age 20–65 years, body mass index (BMI) ≥25 kg/m2and full-time workers.ExposureNight and shift (night/shift) workers were compared with daytime workers in terms of motivation for behavioural change.Primary and secondary outcome measuresThe primary outcome was action and maintenance stages of change (SOC) for lifestyle in TTM. In a subgroup analysis, we investigated interactions between characteristics, including age, sex, BMI, current smoking, alcohol habits, hours of sleep and working hours.ResultsOverall, 1390 participants (15.0%) were night/shift workers; night/shift workers were younger (median age (IQR): 46 (40–54) vs 43 (37–52) years) and the proportion of men was lesser (75.4 vs 60.9%) compared with daytime workers. The numbers of daytime and night/shift workers in the action and maintenance SOC were 2113 (26.9%) and 309 (22.2%), respectively. Compared with daytime workers, night/shift workers were less likely to demonstrate action and maintenance SOC (adjusted OR (AOR): 0.85, 95% CI: 0.74 to 0.98). In a subgroup analysis that included only those with long working hours (≥10 hours/day), results revealed a strong inverse association between night/shift work and action and maintenance SOC (AOR: 0.65, 95% CI: 0.48 to 0.86). A significant interaction was observed between long working hours and night/shift work (P for interaction=0.04).ConclusionsIn workers with overweight or obesity, a night/shift work schedule was associated with a lower motivation for behavioural change in lifestyle, and the association was strengthened in those with long working hours.

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Night shift work, long working hours and dementia: a longitudinal study of the Danish Work Environment Cohort Study

BMJ Open ◽

10.1136/bmjopen-2018-027027 ◽

2019 ◽

Vol 9 (5) ◽

pp. e027027 ◽

Cited By ~ 5

Author(s):

Kirsten Nabe-Nielsen ◽

Åse Marie Hansen ◽

Kazi Ishtiak-Ahmed ◽

Matias Brødsgaard Grynderup ◽

Finn Gyntelberg ◽

...

Keyword(s):

Risk Factors ◽

Longitudinal Study ◽

Shift Work ◽

Night Shift ◽

Working Hours ◽

Long Working Hours ◽

Night Shift Work ◽

Dementia Risk ◽

Potential Risk Factors ◽

Rate Ratios

ObjectiveShift work and long working hours are potential risk factors for dementia, but previous studies on shift work, long working hours and dementia are sparse and their findings are conflicting. Therefore, we investigated the effect of night shift work and long working hours on dementia.DesignA longitudinal study.SettingDenmark.Participants3435 occupationally active men and women from the general working population.MethodsWork schedule covered day work (reference) and shift schedules without/with night work. Working hours covered <27, 28–36, 37 (reference), 38–44, and ≥45 hours/week. As the primary outcome, we used register-based information about dementia, and estimated incidence rate ratios (IRR) and 95% CI. Estimates were adjusted for gender, age, psychosocial work factors and cardiovascular risk factors.ResultsWe identified 85 dementia cases during a mean of 9.8 years of follow-up. We found a positive, but statistically insignificant association between night shift work and dementia (IRR=2.01; 95% CI: 0.87-4.65). Post hoc analyses indicated that this was only due to a higher risk in permanent night workers (IRR=3.25; 95% CI: 1.35-7.83). The dementia risk was also significantly higher among participants working 38–44 hours/week (IRR=2.08; 95% CI: 1.11-3.90) compared with those working 37 hours/week. We found no indications of a higher risk of dementia in participants working <37 hours/week or ≥45 hours/week.ConclusionWe did not find arguments that night shift work or long working hours increased dementia risk in general. However, we found a higher risk of dementia in specific subgroups, that is, permanent night workers and employees with moderately longer weekly working hours than the standard.

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Klokwerk + study protocol: An observational study to the effects of night–shift work on body weight and infection susceptibility and the mechanisms underlying these health effects

BMC Public Health ◽

10.1186/s12889-016-3317-1 ◽

2016 ◽

Vol 16 (1) ◽

Cited By ~ 8

Author(s):

Bette Loef ◽

Debbie van Baarle ◽

Allard J. van der Beek ◽

Linda W. van Kerkhof ◽

Daniëlla van de Langenberg ◽

...

Keyword(s):

Body Weight ◽

Observational Study ◽

Health Effects ◽

Shift Work ◽

Study Protocol ◽

Night Shift ◽

Night Shift Work ◽

Infection Susceptibility

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Intraindividual association between shift work and risk of drinking problems: data from the Finnish Public Sector Cohort

Occupational and Environmental Medicine ◽

10.1136/oemed-2020-107057 ◽

2021 ◽

pp. oemed-2020-107057

Author(s):

Wan-Ju Cheng ◽

Mikko Härmä ◽

Aki Koskinen ◽

Mika Kivimäki ◽

Tuula Oksanen ◽

...

Keyword(s):

At Risk ◽

Public Sector ◽

Shift Work ◽

High Intensity ◽

Lower Risk ◽

Night Shift ◽

Drinking Behaviour ◽

Night Shift Work ◽

Drinking Problems ◽

Increased Risk

ObjectivesStudies concerning the association between shift work and drinking problems showed inconsistent results. We used data from a large occupational cohort to examine the association between shift work and different types of drinking behaviour.MethodsA total of 93 121 non-abstinent workers from the Finnish Public Sector Study were enrolled in the study. Six waves of survey data were collected between 2000 and 2017. Work schedules were categorised as regular day, non-night shift and night shift work, and shift intensities were calculated from registered working hour data. Two indicators of adverse drinking behaviour were measured: at-risk drinking (>7 and >14 drinks per week in women and men, respectively) and high-intensity drinking (measured as pass-out experience). Intraindividual analysis was conducted using fixed-effects regression to examine the association between shift work and drinking behaviours.ResultsCompared with regular day work, night shift work was associated with an increased risk of high-intensity drinking (OR 1.28, 95% CI 1.07 to 1.52) but a lower risk of at-risk drinking (OR 0.85, 95% CI 0.74 to 0.99). Shift workers who worked long shifts had a lower risk of at-risk drinking compared with those who rarely worked long shifts (OR 0.58, 95% CI 0.37 to 0.93).ConclusionsAssociations between shift work and alcohol use vary according to drinking patterns. Workers engaged in high-intensity drinking more often during night shift schedules compared with day work, but did not drink averagely higher volume.

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The Impact Of Fatigue And Night Shift-work On Police Officer Use Of Force, Social Interaction, And Post-shift Driving Performance

PsycEXTRA Dataset ◽

10.1037/e505972017-001 ◽

2017 ◽

Author(s):

Stephen James ◽

Lois James ◽

Bryan Vila

Keyword(s):

Social Interaction ◽

Police Officer ◽

Shift Work ◽

Night Shift ◽

Use Of Force ◽

Driving Performance ◽

Night Shift Work ◽

The Impact ◽

Post Shift

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Nighttime Blue Light Exposure and Breast Cancer

Osteopathic Family Physician ◽

10.33181/13013 ◽

2021 ◽

pp. 30-33

Author(s):

David Jaynes ◽

Paul Switzer

Keyword(s):

Breast Cancer ◽

Risk Factor ◽

Blue Light ◽

Shift Work ◽

Light Exposure ◽

Night Shift ◽

Background Information ◽

Common Disease ◽

Essential Information ◽

Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

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