Sleep duration and quality in permanent night work: an observational field study.

Purpose: Permanent night workers conceivably show better adaptation of circadian rhythms to night work than shift workers and therefore better possibilities of obtaining sufficient sleep of good quality after night shifts. We investigated the effect of night shifts including number of consecutive shifts on sleep among self-selected permanent night workers, and studied if the effect of night shifts differed between morning and evening types and compared with 3-shift workers.

Methods: The study population included 90 permanent night workers followed for 14 days (warehouse workers, 1228 observation days, 80% males).

Validity of self-reported night shift work among women with and without breast cancer.

Objectives: This study aimed to estimate the validity of self-reported information on ever-night shift work among women with and without breast cancer and illustrate the consequences for breast cancer risk estimates.

Methods: During 2015-2016, 225 women diagnosed with breast cancer and 1800 matched controls without breast cancer employed within the Danish hospital regions during 2007-2016 participated in a questionnaire-based survey. Their reported night shift work status was linked with objective payroll register day-by-day working hour data from the Danish Working Hour Database and the Danish Cancer Registry.

Night and evening shifts and risk of calling in sick within the next two days - a case-crossover study design based on day-to-day payroll data.

Objective: Night and evening work is associated with risk of sickness absence, but little is known about the acute effects of these types of shifts on sickness absence. The aim of the current study is therefore to examine the risk of calling in sick within two days after a night or an evening shift.

Methods: By use of a case-crossover design, odds of calling in sick within two days after a night or an evening shift compared to day shifts were analyzed within the same person.

Hair cortisol, glucocorticoid gene receptor polymorphisms, stress, and testicular function.

Objective: Self-reported psychological stress has been associated with decreased semen quality. Cortisol levels in scalp hair (hair cortisol concentration, HCC) has emerged as a potential objective marker of psychological stress. Thus, we investigated if HCC was associated with markers of testicular function.

Self-Reported Sleepiness after 2, 4, and 7 Consecutive Night Shifts and Recovery Days in Danish Police Officers.

Background: Night shift work often implies shorter sleep duration and this can lead to sleepiness, which has been associated with an increased risk of accidents and injuries. The aim is to study how the number of consecutive night shifts affects self-reported sleepiness.

Participants And Methods: The study was a quasi-experimental, within-subject crossover study with 73 police officers.

Heart rate variability during sleep after two, four and seven consecutive night shifts and recovery days: a cross-over intervention study.

Objective: Recovery after shift work is an important part reducing the health problems related to shift work. Heart rate variability (HRV) is an indicator of the balance between sympathetic and parasympathetic activity in the autonomic nervous system and can be used as a measure of recovery after night shifts. The aim of the study is to investigate autonomic recovery during sleep in response to night work in a crossover intervention study.

Educational attainment in young adulthood and self-rated health in midlife - Does allostatic load mediate the association?

This study aimed to examine the extent to which allostatic load (AL), measured in midlife, mediates the association between educational attainment in young adulthood and self-rated health (SRH) in midlife among women and men. The study used data from the Copenhagen Aging and Midlife Biobank (CAMB; n = 5467 participants, aged 48-62 years, 31.5% women).

A longitudinal study of morning, evening, and night light intensities and nocturnal sleep quality in a working population.

We aimed to investigate whether higher light intensity in the morning is associated with better nocturnal sleep quality and whether higher light intensities in the evening or night have the opposite effect. Light intensity was recorded for 7 consecutive days across the year among 317 indoor and outdoor daytime workers in Denmark (55-56° N) equipped with a personal light recorder. Participants reported sleep quality after each nocturnal sleep.

Work-unit measures of psychosocial job stressors and onset of bullying: a 2-year follow-up study.

Objectives: Numerous studies have examined the health consequences of workplace bullying, but little is known about workplace antecedents of workplace bullying. This study examines whether high psychological demands, low levels of justice at work, and low decision latitude increase the occurrence of being bullied or witnessing bullying.

Methods: In 2007, 4489 Danish public employees answered a questionnaire with follow-ups in 2009 (72%) and 2011 (73% of 2009 respondents).

Exposure to workplace violence and threats and risk of depression: a prospective study.

Objectives: Several studies have examined the health consequences of workplace threats and violence, however, due to methodological issues the epidemiological evidence is limited. The purpose of this study was to examine the prospective association between self-labelled exposure to work-related threats and violence and the risk of depression, measured by a standardized psychiatric interview and new prescriptions of anti-depressive medication.

Methods: Employees were recruited from the Danish PRISME cohort established in 2007 where 4489 Danish public employees answered a postal questionnaire with follow-ups in 2009 and 2011.

Socioeconomic Position and Late-Onset Dementia: A Nationwide Register-Based Study.

Objectives: Previous research on the association between socioeconomic position (SEP) and dementia has not sufficiently accounted for the complex relationship between education and occupation. We investigated the independent and joint effects of educational attainment and occupation-based SEP on dementia.

Methods: We used register-based information about educational attainment, occupation-based SEP, and dementia from 1,210,720 individuals.

Labour market affiliation among non-bullied colleagues at work units with reported bullying.

Aim: This study investigates if non-bullied employees in Work units (WUs) where bullying occur, are more prone to leave the WUs than employees in WUs with no bullying, and if the prevalence of workplace bullying had an impact on leaving the WUs. Leaving the workplace was defined by unemployment or change of workplace at follow-up.

Methods: We had data from 8326 Danish public health invited employees from 302 WUs.

COVID-19 risk management at the workplace, fear of infection and fear of transmission of infection among frontline employees.

Objectives: We compared COVID-19 risk management, fear of infection and fear of transmission of infection among frontline employees working within eldercare, hospital/rehabilitation, psychiatry, childcare and ambulance service and explored if group differences in fear of infection and transmission could be explained by differences in risk management. We also investigated the association of risk management with fear of infection and fear of transmission of infection among eldercare personnel.

Methods: We used cross-sectional questionnaire data collected by the Danish labour union, FOA .

The effect of occupational physical activity on dementia: Results from the Copenhagen Male Study.

Leisure-time physical activity (LTPA) reduces the risk of dementia, while the effect of occupational physical activity (OPA) on dementia is uncertain. Therefore, the aim of this study was to investigate the effect of OPA on dementia. For comparison, also the association between LTPA and dementia was analyzed.

Acute effects of night work and meals on blood glucose levels.

Employees working at night are at increased risk of diabetes. A possible mechanism is related to differences in glucose regulation at night. Laboratory simulated night work studies show regulation of blood glucose is impaired at night.

The Effect of Psychosocial Work Factors on Headache: Results From the PRISME Cohort Study.

Objective: To investigate the cross-sectional and longitudinal association between psychosocial work factors, assessed as work-unit averages, and headache. For comparison, we also applied individual exposure measures.

Methods: We used questionnaire-data on headache and psychosocial work factors (PWF).

How to schedule night shift work in order to reduce health and safety risks.

Objectives This discussion paper aims to provide scientifically based recommendations on night shift schedules, including consecutive shifts, shift intervals and duration of shifts, which may reduce health and safety risks. Short-term physiological effects in terms of circadian disruption, inadequate sleep duration and quality, and fatigue were considered as possible links between night shift work and selected health and safety risks, namely, cancer, cardio-metabolic disease, injuries, and pregnancy-related outcomes. Method In early 2020, 15 experienced shift work researchers participated in a workshop where they identified relevant scientific literature within their main research area.

Does Midlife Forgetfulness Influence Positive and Negative Aspects of Social Relations at Work?: Results From the Danish Working Environment Cohort Study.

Objectives: We investigated whether midlife forgetfulness was prospectively associated with changes in social relations at work (SRW) among occupationally active individuals in Denmark.

Methods: We analyzed data of 2339 men and women participating in the first (1990) and second (1995) survey of the Danish Work Environment Cohort Study, responding to questions on working environment, SRW, and forgetfulness. We used multiple linear regression analysis while adjusting for potential confounders.

The urinary 6-sulfatoxymelatonin level after three different work schedules with 2, 4 and 7 consecutive night shifts among Danish police officers.

Night shift work suppresses excretion of melatonin, but little is known about the needed time for recovery. We aimed to compare levels of 6-sulfatoxy melatonin after three different night shift schedules, including recovery days. In a quasi-experimental, within-subject crossover study, 73 male police officers in Denmark collected morning urine after the last recovery day in three different work schedules with two, four, and seven consecutive night shifts followed by a corresponding number of days for recovery.

Mid- to late-life migraine diagnoses and risk of dementia: a national register-based follow-up study.

Background: Previous studies found an association between migraine and dementia, which are two leading causes of disability. However, these studies did not differentiate between migraine types and did not investigate all prevalent dementia subtypes. The main objective of this national register-based study was to investigate whether migraine was a risk factor for dementia.

Impact of psychological stress measured in three different scales on testis function: A cross-sectional study of 1362 young men.

Background: Studies have reported associations between psychological stress and semen quality, but most have been performed on selected populations using different stress measures. Thus, it is uncertain which stress scale best quantifies the effects of stress on testicular function.

Objective: To study the association between three different measures of stress and testicular function in young men.

Working time characteristics and long-term sickness absence among Danish and Finnish nurses: A register-based study.

Background: Working time regimes in Denmark and Finland share many similarities such as nursing personnel working in highly irregular shift systems. Yet, there are also differences for example in policy on when and how the employers are compensated for sickness absence.

Objective: We aimed to investigate the association between different working hour characteristics and long-term sickness absence and whether these associations differed within various age groups in two large datasets of nursing personnel from Denmark and Finland.