Project description:The immune system potentially plays an important mechanistic role in the relation between shift work and adverse health effects. To better understand the immunological effects of shift work, we compared numbers and functionality of immune cells between night-shift and non-shift workers. Blood samples were collected from 254 night-shift and 57 non-shift workers employed in hospitals. Absolute numbers of monocytes, granulocytes, lymphocytes, and T cell subsets were assessed. As read out of immune function, monocyte cytokine production and proliferative capacity of CD4 and CD8 T cells in response to various stimuli were analysed. The mean number of monocytes was 1.15 (95%-CI = 1.05-1.26) times higher in night-shift than in non-shift workers. Furthermore, night-shift workers who worked night shifts in the past three days had a higher mean number of lymphocytes (B = 1.12 (95%-CI = 1.01-1.26)), T cells (B = 1.16 (95%-CI = 1.03-1.31)), and CD8 T cells (B = 1.23 (95%-CI = 1.05-1.45)) compared to non-shift workers. No differences in functional parameters of monocytes and lymphocytes were observed. The differences in numbers of monocytes and T cells suggest that chronic exposure to night-shift work as well as recent night-shift work may influence the immune status of healthcare workers. This knowledge could be relevant for preventive initiatives in night-shift workers, such as timing of vaccination.
Project description:Aims/hypothesisShift-work is associated with circadian rhythm disruption and an increased risk of obesity and type 2 diabetes. We sought to determine the effect of rotational shift-work on glucose metabolism in humans.MethodsWe studied 12 otherwise healthy nurses performing rotational shift-work using a randomised crossover study design. On each occasion, participants underwent an isotope-labelled mixed meal test during a simulated day shift and a simulated night shift, enabling simultaneous measurement of glucose flux and beta cell function using the oral minimal model. We sought to determine differences in fasting and postprandial glucose metabolism during the day shift vs the night shift.ResultsPostprandial glycaemic excursion was higher during the night shift (381±33 vs 580±48 mmol/l per 5 h, p<0.01). The time to peak insulin and C-peptide and nadir glucagon suppression in response to meal ingestion was also delayed during the night shift. While insulin action did not differ between study days, the beta cell responsivity to glucose (59±5 vs 44±4 × 10-9 min-1; p<0.001) and disposition index were decreased during the night shift.Conclusions/interpretationImpaired beta cell function during the night shift may result from normal circadian variation, the effect of rotational shift-work or a combination of both. As a consequence, higher postprandial glucose concentrations are observed during the night shift.
Project description:ImportanceRotating night shift work is associated with higher mortality. Whether it is also associated with overall health among those who survive to older ages remains unclear.ObjectiveTo examine whether rotating night shift work is associated with healthy aging after 24 years of follow-up in the Nurses' Health Study, a cohort study among registered female nurses.Design, setting, and participantsFor this cohort study, a composite healthy aging phenotype was ascertained among 46 318 participants who were aged 46 to 68 years and free of major chronic diseases in 1988 when the history of night shift work was assessed. In a secondary analysis in which cognitive function decline was considered in the healthy aging definition, 14 273 nurses were involved. Data were analyzed from March 1 to September 30, 2021.ExposuresDuration of rotating night shift work.Main outcomes and measuresHealthy aging was defined as reaching at least 70 years of age and being free of 11 major chronic diseases, memory impairment, physical limitation, or deteriorated mental health.ResultsOf 46 318 female nurses (mean [SD] age at baseline, 55.4 [6.1] years), 3695 (8.0%) achieved healthy aging after 24 years of follow-up. After adjusting for established and potential confounders, compared with women who never worked rotating night shifts, the odds of achieving healthy aging decreased significantly with increasing duration of night shift work. The odds ratios were 0.96 (95% CI, 0.89-1.03) for 1 to 5 years, 0.92 (95% CI, 0.79-1.07) for 6 to 9 years, and 0.79 (95% CI, 0.69-0.91) for 10 or more years of night shift work (P = .001 for trend). This association did not differ substantially by age and lifestyles and was consistent for 4 individual dimensions of healthy aging. Results were similar in a secondary analysis, with an odds ratio of 0.73 (95% CI, 0.60-0.89; P < .001 for trend) comparing 10 or more years of night shift work vs no night shift work.Conclusions and relevanceIn this cohort study, rotating night shift work was associated with decreased probability of healthy aging among US female nurses. These data support the notion that excess night shift work is a significant health concern that may also lead to deteriorated overall health among older individuals.
Project description:Shift work is associated with impaired alertness and performance due to sleep loss and circadian misalignment. This study examined sleep between shift types (day, evening, night), and alertness and performance during day and night shifts in 52 intensive care workers. Sleep and wake duration between shifts were evaluated using wrist actigraphs and diaries. Subjective sleepiness (Karolinska Sleepiness Scale, KSS) and Psychomotor Vigilance Test (PVT) performance were examined during day shift, and on the first and subsequent night shifts (3rd, 4th or 5th). Circadian phase was assessed using urinary 6-sulphatoxymelatonin rhythms. Sleep was most restricted between consecutive night shifts (5.74 ± 1.30 h), consecutive day shifts (5.83 ± 0.92 h) and between evening and day shifts (5.20 ± 0.90 h). KSS and PVT mean reaction times were higher at the end of the first and subsequent night shift compared to day shift, with KSS highest at the end of the first night. On nights, working during the circadian acrophase of the urinary melatonin rhythm led to poorer outcomes on the KSS and PVT. In rotating shift workers, early day shifts can be associated with similar sleep restriction to night shifts, particularly when scheduled immediately following an evening shift. Alertness and performance remain most impaired during night shifts given the lack of circadian adaptation to night work. Although healthcare workers perceive themselves to be less alert on the first night shift compared to subsequent night shifts, objective performance is equally impaired on subsequent nights.
Project description:The occurrence of the shift work disorder (SWD) in health-care workers (HCWs) employed in 24/7 hospital wards is a major concern through the world. In accordance with literature, SWD is the most frequent work-related disturb in HCWs working on shift schedules including night shift. In agreement with the Luxembourg Declaration on workplace health promotion (WHP) in the European Union, a WHP program has been developed in a large Hospital, involving both individual-oriented and organizational-oriented measures, with the aim to prevent the occurrence of SWD in nurses working on shifts including night shift. The objective assessment of rotating shift work risk and the excessive sleepiness were detected before and after the implementation of the WHP program, by using the Rotating Shiftwork-questionnaire and the Epworth Sleepiness Scale. The findings of this study showed the effectiveness of the implemented WHP program in minimizing the impact of shift work on workers' health and in preventing the misalignment between sleep-wake rhythm and shift working.
Project description:Objective This study aimed to investigate a prospective association between shift work and use of psychotropic medicine. Methods Survey data from random samples of the general working population of Denmark (N=19 259) were linked to data from national registers. Poisson regression was used for analyses of prospective associations between shift work and redeemed prescriptions of psychotropic medicine. Prevalent cases were excluded at baseline. In secondary analyses, we tested differential effects on subsets of psychotropic medicine and, cross-sectionally, we studied correspondence between estimates based on psychotropic medicine and self-reported mental health. According to the protocol we interpret results from the secondary analyses following the principles for nested hypothesis testing, if the primary analyses reject the null-hypothesis, and otherwise we regard it as hypothesis generating exploratory analyses. Results In the primary analysis, the rate ratio for incidence of psychotropic medicine among shift workers was 1.09 (95% confidence interval 0.99-1.21). Results from the secondary analyses suggested increased incidence of use of hypnotics, sedatives and antidepressants and decreased incidence of use of anxiolytics. Cross-sectional analysis suggested increased risk for use of psychotropic medicine (all kinds), but not for poor self-rated mental health. Conclusions Results did not support that working in shifts to the extent that is currently practiced in Denmark is associated with an increased incidence of overall psychotropic medicine use. Future studies should test, whether there is a differential incidence for different drugs among shift workers as suggested by the secondary analyses and how psychotropic medicine use and mental health are related.
Project description:ObjectiveShift work and Shift Work Sleep Disorder (SWSD) are known to affect the secretion of several neurotransmitters and hormones associated with premature ejaculation (PE). However, their specific influence on the regulation of male ejaculation remains unclear. This study explores the relationship between shift work, SWSD, and PE.MethodsFrom April to October 2023, a cross-sectional survey was conducted across five regions of China to explore the work schedules, sleep quality, and sexual function of male workers. Participants' sleep quality was evaluated using a validated SWSD questionnaire, and their erectile function and ejaculatory control were assessed with the International Inventory of Erectile Function (IIEF-5) scores and Premature Ejaculation Diagnostic Tool (PEDT) scores, respectively. Univariate and multivariate linear regression analyses were employed to identify risk factors associated with PE. Confounders were controlled using multiple regression models, and clinical prediction models were developed to predict PE onset and assess the contribution of risk factors.ResultsThe study included 1239 eligible participants, comprising 840 non-shift workers and 399 shift workers (148 with SWSD and 251 without SWSD). Compared to non-shift working males, those involved in shift work (β 1.58, 95% CI 0.75 - 2.42, p < 0.001) and those suffering from SWSD (β 2.86, 95% CI 1.86 - 3.85, p < 0.001) they had significantly higher PEDT scores. Additionally, we identified daily sleep of less than six hours, depression, anxiety, diabetes, hyperlipidemia, frequent alcohol consumption (more than twice a week), and erectile dysfunction as risk factors for PE. The predictive model for PE demonstrated commendable efficacy.ConclusionBoth shift work and SWSD significantly increase the risk of premature ejaculation, with the risk magnifying in tandem with the duration of shift work. This study reveals the potential impact of shift work and SWSD on PE and provides new theoretical foundations for the risk assessment and prevention of this condition.
Project description:Shift work, defined as work occurring outside typical daytime working hours, is associated with an increased risk for metabolic syndrome (MetS) due to several biological and environmental changes. The MetS refers to the clustering of several known cardiovascular risk factors, including insulin resistance, obesity, dyslipidemia, and hypertension. This systematic review aims to evaluate the literature on the association between shift work and the risk of MetS in employees of the health sector. A systematic search was conducted in PubMed, Web of Science, and Scopus databases using appropriate keywords for studies published before September 1, 2021. Eligible studies were those that compared the prevalence of MetS between day and shift healthcare workers; had a cross-sectional, case-control, or cohort study design; provided sufficient data for calculating odds ratios or relative risks with 95% confidence intervals; and articles in English. The Joanna Briggs Institute prevalence critical appraisal tool was used for quality analysis. Risk for MetS and related measures of effect size were retrieved from studies for meta-analysis. Twelve studies met the criteria for inclusion in the review and meta-analysis. Sample sizes ranged from 42 to 738, and the age range of subjects was between 18 and 65 years. Ten studies demonstrated high methodological quality, while two studies were of average quality. Ten out of 12 studies in the review demonstrated a higher risk in shift workers for developing MetS than day workers. The pooled OR of MetS in shift workers based on 12 studies was 2.17 (95% CI = 1.31-3.60, P = 0.003; I2 = 82%, P < 0.001). Shift workers exhibited more than a twofold increase in the chance of developing MetS in comparison with day workers.
Project description:We evaluated the eating pattern, physical activity, and daytime sleepiness level in Chilean shift workers. Fifty, middle-aged adult health workers from a public hospital in Santiago, Chile, were included: a group undergoing shift work (shift workers, including at least one "night shift" and one "long day", n = 33), and day workers under traditional schedule (from 8:00 to 17:00h, n = 17). Body composition, physical activity, and daytime sleepiness levels, and diet characteristics (diet composition, meals' timing, and diet quality) were assessed. Despite similar total energy intake, shift worker showed lower carbohydrate (% of energy) and higher protein intake (both P < 0.01), decreased diet quality, an irregular eating pattern, and delayed meal timing (all P < 0.05). Physical activity and daytime sleepiness levels did not differ between groups. Findings from this first Chilean study in healthcare shift workers support the fact that meal timing and diet quality appear as critical factors for upcoming intervention studies in this group.
Project description:Recently, there has been interest in whether shift work may enhance susceptibility to infection. Our aim was to determine whether shift workers in the health-care field have a higher incidence, duration, and/or severity of influenza-like illness (ILI) and acute respiratory infection (ARI) than non-shift workers. From September 2016 to June 2017, 501 rotating and/or night-shift workers and 88 non-shift workers from the Klokwerk+ Study (the Netherlands, 2016-2017) registered the occurrence of ILI/ARI symptoms daily using a smartphone application. The incidence rate of ILI/ARI (defined as ≥2 symptoms on the same day/≥1 symptom on 2 consecutive days), the mean duration of each episode, and the incidence rate of severe episodes were compared between shift workers and non-shift workers using negative binomial regression and linear mixed-model analysis. In total, participants completed 110,347 diaries. Shift workers' incidence rate of ILI/ARI was 1.20 (95% confidence interval (CI): 1.01, 1.43) times higher than that of non-shift workers, and for severe ILI/ARI episodes, shift workers' incidence rate was 1.22 (95% CI: 1.01, 1.49) times higher. The mean duration of an ILI/ARI episode did not differ (ratio between means = 1.02, 95% CI: 0.87, 1.19). In conclusion, shift workers in health care had more ILI/ARI episodes and more severe ILI/ARI episodes than non-shift workers, but with a similar duration. Insight into underlying mechanisms connecting shift work and infection susceptibility will contribute to the design of preventive initiatives.