Associations of night shift work with weight gain among female nurses in The Netherlands: results of a prospective cohort study.

OBJECTIVE: This study aimed to prospectively investigate associations of working night shifts with weight gain in the Nightingale Study, a large cohort of female nurses. METHODS: This study included 36 273 registered nurses, who completed questionnaires in 2011 and 2017. Cumulative number of nights, mean number of nights/month and consecutive number of nights/month in 2007-2011 were assessed. We used Poisson regression to estimate multivariable-adjusted incidence rate ratios (IRR) of >5% weight gain from 2011 to 2017 among all participants and assess risk of development of overweight/obesity (BMI≥25 kg/m2) among women with healthy baseline body mass index. The reference group consisted of women who never worked nights. RESULTS: Overall, working night shifts in 2007-2011 was associated with >5% weight gain [IRR 1.07, 95% confidence interval (CI) 1.01-1.13]. Associations differed by menopausal status in 2011, with an increased risk of gaining >5% weight limited to postmenopausal women who worked nights (IRR 1.23, 95% CI 1.10-1.38). Postmenopausal women had an increased risk of >5% weight gain when they worked on average ≥4 nights/month (4-5: IRR 1.29, 95% CI 1.09-1.52, ≥6: IRR 1.27, 95% CI 1.11-1.47) or ≥4 consecutive nights/month (IRR 1.37, 95% CI 1.19-1.58), compared to postmenopausal women who never worked nights. For postmenopausal women with healthy weight at baseline, night shift work was associated with an increased risk of overweight/obesity at follow-up (IRR 1.24, 95% CI 1.03-1.50). CONCLUSIONS: Working night shifts was associated with a slightly increased risk of weight gain and overweight/obesity development among women who were postmenopausal at study inclusion. Our findings emphasize the importance of health promotion to maintain a healthy weight among (postmenopausal) night workers.

Influence of chronotype on sleep quality and menstrual regularity in nurses on monthly shift rotations.

OBJECTIVES: This study aimed to investigate factors that influence the sleep quality and menstrual cycles of female rotating-shift nurses. METHODS: A cross-sectional study was conducted in which 213 female rotating-shift nurses between the ages of 20 and 45 were recruited from a medical center in Taiwan from November 1, 2023, to December 31, 2023. Binary logistic regression analysis was performed with regard to sleep quality or menstrual cycle. RESULTS: Female rotating-shift nurses who perceived a higher level of stress (P < .001), were late chronotypes (P = .020), or were working the night shift (P = .006) were more likely to have poor sleep quality. Late-type nurses working the day shift were more likely to have poor sleep quality than were early- and intermediate-type nurses (P < .001). With regard to menstrual cycles, female rotating-shift nurses who perceived a higher level of stress (P = .008), were working the night shift (P < .001), or had poor sleep quality (P = .001) were more likely to have irregular menstrual cycles. Late-type nurses working the day shift were more likely to have irregular menstrual cycles than were early- and intermediate-type nurses (P = .013). CONCLUSIONS: A higher likelihood of poor sleep quality was found in female rotating-shift nurses when they perceived high levels of stress, and the interactions between chronotype and shift type could influence sleep quality. Shift type and the interactions between chronotype and shift type could also influence menstrual regularity.

Melatonin hormone level in nurses and factors affecting it; Investigation according to shift working pattern.

This study aimed to determine the relationship between melatonin hormone levels, sleep, and factors affecting sleep, psychological resilience, and depression in nurses working with a shift work system. Conducted between February 5-12, 2021, at the Training and Research Hospital in Agri province, the descriptive study included 41 night shift nurses and 35 day shift nurses, totaling 76 participants. Blood samples for melatonin analysis were collected and data were gathered using the Sociodemographic Information Form, Epworth Sleepiness Scale, Sleep Disorder Scale Short Form, Brief Psychological Resilience Scale, and Beck Depression Scale Short Form. Melatonin analysis was performed using the ELISA method. Statistical significance was set at p < 0.05. Results showed that sleep disorders were present in all nurses with <7 h of daily sleep. Factors such as the use of sleeping pills, marital status, age, and gender affected sleep disorders. Mean scores for melatonin levels were 67.82 ± 40.20 for night shift nurses and 68.08 ± 39.62 for day shift nurses, with no significant difference between shifts. Similarly, no significant differences were found in daytime sleepiness (7.49 ± 4.47 vs. 7.51 ± 4.65), sleep disturbance (24.71 ± 7.33 vs. 25.23 ± 6.64), psychological resilience (18.42 ± 4.19 vs. 17.89 ± 4.74), or depression (3.22 ± 2.60 vs. 3.49 ± 3.35). Nurses exhibited mild sleep disturbances, low depression tendencies, and moderate psychological resilience. Increased daytime sleepiness and sleep disorders correlated with higher depression tendencies and lower psychological resilience. Hospital management and education units are recommended to conduct interventions on sleep quality, depression, and psychological resilience to raise awareness among nurses.

Personalized sleep and nutritional strategies to combat adverse effects of night shift work: a controlled intervention protocol.

BACKGROUND: Working during the night interferes with the timing of normal daily activities and is associated with an increased risk of chronic diseases. Under controlled experimental conditions, interventions focusing on sleep and nutrition can mitigate the short-term adverse effects of shift work. However, it is unclear how these results translate to real-life, how they can be targeted to individual conditions, and how they relate to long-term health. Therefore, the current study aims to implement a personalized sleep and nutritional intervention among night shift workers in the field. METHODS: A non-blinded controlled intervention study is used, consisting of a run-in period, an intervention of 3 months, post-intervention measurements, and a follow-up after 12 months. Three study arms are included: sleep intervention, nutritional intervention, and control group (n = 25 each). Participants are healthy 18-60-year male night shift workers, with at least one year of experience in night shift work. Information from the run-in period will be used to personalize the interventions. The main outcomes are sleep measurements and continuous interstitial glucose levels. Furthermore, general health biomarkers and parameters will be determined to further evaluate effects on long-term health. DISCUSSION: This study aims to mitigate negative health consequences associated with night shift work by introducing two personalized preventive interventions. If proven effective, the personalized interventions may serve as practical solutions that can have a meaningful impact on the sustainable health and employability of night shift workers. This study will thereby contribute to the current need for high-quality data on preventative strategies for night shift work in a real-life context. TRIAL REGISTRATION: This trial has been registered under ClinicalTrials.gov Identifier NCT06147089. Registered 27 November 2023.

Exploring sleepiness and stress among London bus drivers: An on-road observational study.

Bus driver sleepiness is commonplace but often goes unreported within the industry. Whilst past research has begun to shed a light on the prevalence, potential causes, and consequences of bus driver sleepiness, this is often done using self-report methods. This is the first study to investigate sleepiness amongst city bus drivers on-road using a live bus route with drivers' regular schedules. A total of 16 participants completed two drives of their regular bus route once during an early morning shift and once during a daytime shift whilst physiological and self-report measures of sleep and stress were taken. Prior to these drives, drivers recorded their sleep in a diary and wore an actigraph to obtain objective sleep measures. Results showed that most drivers did not obtain sufficient sleep prior to early morning shifts, and often did not obtain as much sleep as they would need in order to feel rested before work. Sleepiness and stress were observed in both shifts. During early morning shifts sleepiness was likely a result of working during circadian lows and not obtaining enough sleep prior to the shift. In contrast, sleepiness during the daytime shift was likely a result of completing a highly demanding task in complex traffic which not only contributed to fatigue, but also led to increased levels of stress. As well as demonstrating the prevalence of sleepiness amongst bus drivers, these findings show that the causes of sleepiness can be multifaceted and often come about due to a combination of work and personal factors. In addition, the experience of sleepiness is not the same for all drivers, with individual differences in the experience of sleepiness playing a large role. These differences highlight the need for individualised interventions which should be considered by policymakers alongside the combination of causal factors within a larger systems approach.

Shift work and non-alcoholic fatty liver disease in young, healthy workers.

Non-alcoholic fatty liver disease (NAFLD) is a relatively common disease, and preventing its occurrence is important for both individual health and reducing social costs. Shift work is reported to have several negative effects on health. An association has been observed between NAFLD and both sleep time and quality; however, this association remains unclear in night shift workers. We aimed to evaluate the relationship between shift work and the incidence of NAFLD. Overall, 45,149 Korean workers without NAFLD were included at baseline. NAFLD was defined as the presence of a fatty liver observed on ultrasonography without excessive alcohol use. incidence rate ratios for incident NAFLD were estimated using negative binomial regression according to age groups (20s, 30s, 40s, and 50s). In the 20s age group, shift work showed a significant incidence rate ratio (IRR) for NAFLD in all models. After adjusting for all variables, the IRR (95% confidence interval) was 1.24 (1.08-1.43) in the 20s age group. In their 20s, a significant association between shift work and incident NAFLD was consistently observed among women and workers with poor sleep quality. In this large-scale cohort study, shift work was significantly associated with the development of NAFLD among young workers in their 20s.

Sleep Behavior in Royal Australian Navy Shift Workers by Shift and Exposure to the SleepTank App.

INTRODUCTION: Rotating shiftwork schedules are known to disrupt sleep in a manner that can negatively impact safety. Consumer sleep technologies (CSTs) may be a useful tool for sleep tracking, but the standard feedback provided by CSTs may not be salient to shift-working populations. SleepTank is an app that uses the total sleep time data scored by a CST to compute a percentage that equates hours of sleep to the fuel in a car and warns the user to sleep when the "tank" is low. Royal Australian Navy aircraft maintenance workers operating on a novel rotational shift schedule were given Fitbit Versa 2s to assess sleep timing, duration, and efficiency across a 10-week period. Half of the participants had access to just the Fitbit app while the other half had access to Fitbit and the SleepTank app. The goal of this study was to evaluate differences in sleep behavior between shifts using an off-the-shelf CST and to investigate the potential of the SleepTank app to increase sleep duration during the 10-week rotational shift work schedule. MATERIALS AND METHODS: Royal Australian Navy volunteers agreed to wear a Fitbit Versa 2 with the SleepTank app (SleepTank condition), or without the SleepTank app (Controls), for up to 10 weeks from May to July 2023 during the trial of a novel shift rotation schedule. Participants from across 6 units worked a combination of early (6:00 AM to 2:00 PM), day (7:30 AM to 4:30 PM), late (4:00 PM to 12:00 AM), and night shifts (12:00 AM to 6:00 AM) or stable day shifts (6:00 AM to 4:00 PM). Differences in sleep behavior (time in bed, total sleep time, bedtime, wake time, sleep efficiency [SE]) between conditions and shift types were tested using Analysis of Variance. This study was approved by the Australian Departments of Defence and Veterans' Affairs Human Research Ethics Committee. RESULTS: Thirty-four participants completed the full study (n = 17 Controls; n = 17 SleepTank). There was a significant effect of shift type on 24-hour time in bed (TIB24; F(4,9) = 8.15, P < .001, η2 = 0.15) and total sleep time (TST24; F(4,9) = 8.54, P < .001, η2 = 0.18); both were shorter in early shifts and night shifts compared to other shift types. TIB24 and TST24 were not significantly different between conditions, but there was a trend for greater SE in the SleepTank condition relative to Controls (F(1,9) = 2.99, P = .08, η2 = 0.11). CONCLUSIONS: Sleep data collected by Fitbit Versa 2s indicated shorter sleep duration (TIB24, TST24) for Royal Australian Navy workers during early and late shifts relative to stable day shifts. Access to the SleepTank app did not greatly influence measures of sleep duration but may be protective against fatigue by affecting SE. Further research is needed to evaluate the utility of the SleepTank app as a means of improving sleep hygiene in real-world, shift-working environments.

A latent profile analysis of shift work tolerance among Chinese male sailors during a prolonged non-24-h rotating shift schedule at sea.

Shift work tolerance (SWT) refers to the ability to adapt to shift work without significant adverse consequences. The present study aimed to examine the individual differences in SWT and their predictors and outcomes. Latent profile analyses were conducted using cross-sectional data collected form 448 Chinese male sailors who experienced a prolonged (>30 d) non-24-h rotating shift schedule at sea. Depression, anxiety, sleep disturbance, fatigue, domestic disruption, job satisfaction, work engagement, digestive and cardiovascular symptoms were included as indicators of SWT. The results showed that there existed 2 latent profiles of SWT named as High SWT group and Low SWT group. High SWT group was characterized by low levels on all negative bio-psycho-social outcomes but high levels of work engagement and job satisfaction, while Low SWT group exhibited completely opposite characteristics compared to High SWT group. The level of hardiness could predict profile membership that those with higher level of hardiness were more likely to belong to High SWT group. However, there were no significant differences observed in job performance between two groups. In conclusion, hardiness can serve as a predictor of personnel selection for shift work and hardiness-based intervention programs should be encouraged among the shift workers.

Shift Work, Shifted Diets: An Observational Follow-Up Study on Diet Quality and Sustainability among Healthcare Workers on Night Shifts.

This study aimed to investigate the change in diet quality in addition to dietary adherence to the planetary health diet during night shifts in healthcare workers. This observational follow-up study involved 450 healthcare workers working night shifts (327 females, 123 males). A survey form requesting sociodemographic information (gender, age, marital status), job title, sleeping duration during the night shift, 24 h dietary records for pre-night-shift, during night shift, and post-night-shift, and anthropometric measurements (body weight and height) was applied. The scores of the Planetary Health Diet Index (PHDI) and the Healthy Eating Index 2020 (HEI-2020) were calculated according to the dietary records. The total HEI-2020 and PHDI scores decreased significantly (p < 0.05) during the night shift (44.0 ± 8.8 and 48.3 ± 13.2, respectively) compared to pre-night-shift (46.1 ± 9.2 and 51.9 ± 13.4, respectively) and increased post-night-shift (44.7 ± 9.9 and 50.6 ± 14.9, respectively), with no statistically significant difference between pre- and post-night-shift. There was a significant main effect of night shift working on total PHDI (F(896, 2) = 8.208, p < 0.001, ηp2 = 0.018) and HEI-2020 scores (F(894, 2) = 6.277, p = 0.002, ηp2 = 0.014). Despite healthcare workers' knowledge of health factors, night shifts lead to poor dietary choices. To improve diet quality and sustainability, it is crucial to enhance access to healthy food options in their work environment.

A longitudinal study of rotating shift type and attention performance of acute and critical care nurses with chronotype as moderator variable.

OBJECTIVES: To investigate whether chronotype is a moderator variable that also interacts with shift type and whether they jointly influence the attention performance of nurses working in acute and critical care units. METHODS: We adopted a longitudinal research design focusing on nurses working rotating shifts in the emergency room and intensive care units at a medical center. A total of 40 complete samples were obtained. Data analysis was conducted using the generalized estimating equations in SAS 9.4. RESULTS: The mean (SD) age of the participants was 26.35 (2.12) years. After controlling for age, gender, and sleep duration, an interaction effect was discovered between a specific chronotype and shift type; that is, the interaction effect between chronotype and shift type was only significant when comparing late-types working the night shift with early- and intermediate-types working the night shift (B = -18.81, P = .011). The least squares means of the mean reaction time of the interaction effects between the 2 chronotype groups and the 3 shift types found that the mean reaction time of late-types working the night shift was 11.31 ms (P = .044) slower compared with working the day shift. CONCLUSIONS: The chronotype is a moderator variable between shift type and mean reaction time, such that matching the chronotype of nurses in acute and critical care units with the appropriate shift type improved their mean reaction time. It is hoped that the results of this study could serve as a reference for acute and critical care nurses when scheduling their shifts.

Effects of night-float shifts on cognitive function among radiology residents.

BACKGROUND: Many radiology programs utilize a night-float system to mitigate the effects of fatigue, improve patient care, and provide faster report turnaround times. Prior studies have demonstrated an increase in discrepancy rates during night-float shifts. OBJECTIVES: This study was performed to examine the effects of night-float shift work on radiology resident cognition. We hypothesized that there would be diminished cognitive function on testing following night-float shifts when compared to testing following day shifts. METHODS: Diagnostic radiology residents in their second to fifth years of residency at a single institution were recruited to participate in this pilot study. Cognitive function was evaluated using the Lumosity Neurocognitive Performance Tests (NCPT), standardized performance tests that provide real-time, objective measurements of cognitive function. Study participants completed the NCPT in 5 sessions following 5 consecutive day shifts to evaluate their baseline cognitive function. The tests were re-administered at the end of consecutive night-float shifts to assess for any changes. Sleep was objectively monitored using actigraphy devices worn around the wrist during all study weeks. Descriptive and summary statistics were performed. RESULTS: 23 prospectively recruited diagnostic radiology residents working night-float shifts took a mean 13.6 (± 5.1) neurocognitive performance tests during the study period. There was a statistically significant decline in 2 of the 6 cognitive tests administered, signifying a decrease in attention, speed, and complex reasoning ability. Night-float shifts were significantly longer than the day shifts and associated with a significantly higher study volume and cross-sectional study volume. Fitbit data demonstrated that there were no significant differences in level of activity while awake. However, participants slept significantly longer during day shifts. CONCLUSIONS: A sample of 23 radiology residents working night-float shifts demonstrated declines in attention, speed, and complex reasoning ability following sequential administration of standardized neurocognitive performance tests. While the sample size is small, these findings demonstrate the potential deleterious effects of night-float shift work and provide evidence to support further inquiry into this phenomenon.

Sex and race disparities in the association between work characteristics and vitamin D deficiency: findings from the National Health and Nutrition Examination Survey, 2005-2010.

OBJECTIVES: Vitamin D deficiency is highly prevalent worldwide; however, few large population-based studies have examined occupational risk factors. We examined associations between shift work, work schedule, hours worked, outdoor work, occupation and serum 25-hydroxyvitamin D (25(OH)D) levels in the US working population. METHODS: This cross-sectional study included 8601 workers from the 2005-2010 National Health and Nutrition Examination Survey (NHANES) cycles. NHANES occupational data were supplemented with measures of outdoor work from the Occupational Information Network. Serum 25(OH)D concentration in nanomoles per litre (nmol/L) was categorised as sufficient (≥75), insufficient (50-<75), moderately deficient (30-<50) and severely deficient (<30). Age-adjusted weighted multinomial and binary logistic regression were used to examine associations between work-related factors and vitamin D status with sex-race/ethnicity stratification. RESULTS: Shift workers had higher odds of severe vitamin D deficiency compared with day workers (OR: 1.64, 95% CI 1.22 to 2.19). Compared with those in white-collar occupations, those in natural resources were less likely to be deficient (OR: 0.31, 95% CI 0.19 to 0.52), while those in production were more likely to be deficient (OR: 2.25, 95% CI 1.48 to 3.43). Women working ≥40 hours/week compared with <40 hours/week were more likely to be moderately deficient (OR: 1.30, 95% CI 1.06 to 1.59). Black women working in sales were more likely to be deficient than those in management (OR: 1.53, 95% CI 1.03 to 2.27). Mexican American men working nights had the highest odds of deficiency (OR: 2.64, 95% CI 1.38 to 5.06). CONCLUSIONS: Work-related factors were associated with vitamin D status and there were race/ethnicity and sex differences. Targeted vitamin D screening and supplementation interventions may reduce these disparities.

The relationship between night shift work, sleep patterns, psychological well-being, and mental health among Jordanian healthcare workers.

This study examines the associations between working night shifts and various outcomes, including sleep patterns, healthcare workers' sleep quality, and physical, mental, and social well-being. A descriptive cross-sectional study was conducted, where the findings revealed that night shift healthcare workers experienced poor sleep quality and pattern. In addition, night shift healthcare workers were more likely to express their intent to leave, the impact of work on their social lives, and a low level of job satisfaction. Healthcare workers showed moderate anxiety and mild depression levels. Lower job satisfaction correlated with higher anxiety and depression levels among healthcare workers, while the negative impact of working hours on social life was associated with increased anxiety and depression. Organizations should consider establishing comprehensive wellness initiatives covering work-life balance, stress management strategies, and mental health resources.

Pre-pregnancy shift work's influence on postpartum weight retention: Body mass index's role.

Shift work is a prevalent workplace exposure, which increases the possibility of unhealthy behaviours and circadian rhythm disruptions and elevates the risk of metabolic diseases and adverse reproductive outcomes. But its potential of increasing the risk of postpartum weight retention remains uncertain. This study aimed to investigate the association between maternal shift work prior to conception and postpartum weight retention, and to identify modifiable factors during pregnancy for prevention. We analysed data from the Taiwan Birth Cohort Study, a prospective cohort of Taiwanese women who gave birth in 2005. We examined the pre-conceptional shift work status of 13,575 mothers and their body weight before pregnancy, before delivery, six and eighteen months after delivery. We used multivariable linear models to examine associations and effect modifications. Maternal shift work before pregnancy was significantly associated with increased postpartum weight retention at six and eighteen months (ß-estimate for six months: 0.19-kilogram, 95% CI: 0.03-0.34; eighteen months: 0.23-kilogram, 95% CI: 0.04-0.40). The association between shift work and weight retention at six months postpartum was stronger among mothers who were overweight or obese before pregnancy than mothers with normal weight. This study showed the impact of shift work on postpartum weight retention and suggested a stronger association among mothers with overweight or obesity before pregnancy.

Acute effects of a simulated quick return on subjective sleepiness, mood, and cognitive performance: A laboratory crossover controlled trial.

Sleep loss due to short time off between shifts has been proposed as a mechanism contributing to impaired functioning in occupational settings. This laboratory crossover trial (ClinicalTrials.gov identifier: NCT05162105, N = 66) compared subjective sleepiness, mood, and cognitive performance on a day shift after an evening shift with only 8 h off between shifts (quick return, QR) to a day shift after another day shift with 16 h off between shifts (control). Results indicated higher subjective sleepiness (Karolinska Sleepiness Scale) during the QR condition compared to the control condition (p < 0.001). No significant differences were found on mood (Positive and Negative Affect Schedule) and cognitive performance (Psychomotor Vigilance- and Digit Symbol Substitution Test) between the conditions. Findings of increased subjective sleepiness corroborate previous field studies. This trial is to our knowledge the first to compare mood and cognitive performance after a QR to a longer shift transition using an experimental design. Future research should explore the effects of accumulated sleep loss associated with QRs (e.g. having several QRs within a short time period) on behavioral outcomes.

Investigating the relationship between shift work schedule and blood and metabolic parameters: a 10-years retrospective cohort study.

Shift work has become increasingly common in modern society. Shift work has been associated with a range of negative health outcomes. Therefore, this 10-years retrospective cohort study, aimed to investigate the relationship between shift work and blood and metabolic parameters. This retrospective cohort study was conducted in a metal parts manufacturing industry in 2023. In this study, 204 shift workers and 204 day workers were examined. All the studied blood and metabolic parameters were collected by reviewing the medical records of all participants during a 10-years period (2013-2022). Moreover, the amounts of physical, chemical, and ergonomics harmful agents in the work environment were investigated. All the collected data were analyzed using SPSS version 25.0. The values of Body Mass Index (BMI), Red Blood Cell Count (RBC), Platelets Count (PLT), Thyroid-Stimulating Hormone Level (TSH), Fasting Blood Sugar Level (FBS), Creatinine, Triglyceride (TG), Liver Enzymes level (SGOT and SGPT), and Systolic Blood Pressure (SBP) were higher among the shift work employees, and a significant difference was observed between the values of these parameters between the two groups. The results of logistic regression showed that the highest effect of shift work was observed on the parameters of FBS, TG, SGPT, TSH, Physical activity, BMI, Sleep duration, PLT, and Sleep quality with beta coefficient values of 0.49, 0.33, 0.29, 0.29, 0.20, 0.18, 0.14, 0.13 and, 0.11, respectively (p-value < 0.01). The present study contributes to a growing body of evidence that blood and metabolic factors are likely to be influenced by shift work. These findings have important implications for policy makers, highlighting the need for interventions to mitigate the negative health effects of shift work on workers.

Relationship between social jetlag and body mass index in nurses working shift schedules: a cross-sectional study.

This study aimed to explore the relationship between shift-working nurses' social jetlag and body mass index (BMI) and provide a theoretical basis for nursing managers to develop appropriate health interventions. Shift work is unavoidable in nursing and is associated with circadian rhythm disorders. Social jetlag is prevalent in shift-working nurses and is associated with adverse health outcomes (particularly metabolism-related indicators). BMI is a significant metabolic indicator, and research has demonstrated its effectiveness in predicting the formation of metabolic syndrome. The relationship between social jetlag and BMI can be explained by considering physiological, psychological, and behavioral factors. However, most studies on social jetlag and health status are focused on non-shift nurse populations, with fewer studies on shift workers. Five tertiary hospitals located at similar latitudes in Southwest China were selected for the study. We surveyed 429 shift-working nurses using sociodemographic data, the Munich Chronotype Questionnaire for Shift Workers, and BMI. The restricted cubic spline model was used to analyze the relationship between social jetlag and BMI among shift-working nurses, and segmented linear regression was performed around the inflection point using multiple linear regression analysis. The results revealed that social jetlag (82.0 [85.0] min) was experienced by 64.6% of the shift-working nurses. After controlling for confounding variables, the model with seven knots had the lowest accepted Akaike information criterion value, and there was a U-shaped relationship between shift-working nurses' BMI and social jetlag in this model; its inflection (lowest) point of 20.7 was considered the cut-off point. Segmented regression showed that for BMI < 20.7, BMI was significantly negative with standardized social jetlag; whereas with BMI > 20.7, BMI was significantly positive with standardized social jetlag. BMI has a U-shaped relationship with social jetlag, and attention should be paid to overweight or underweight shift-working nurses to detect early circadian rhythm disorder. Shift-working nurses with high social jetlag tended to have higher/lower BMI, which should be further investigated in the future, to minimize metabolic diseases among them.

The influence of night shift work and associated factors on serum uric acid in aircraft maintenance workers.

BACKGROUND AND OBJECTIVE: The prevalence of 12-hour shift work is increasing in various occupations. Shift work has been linked to circadian rhythm disruption, which may lead to hormonal changes and metabolic disorders, including alterations in glucose, lipid, and purine metabolism. Despite this, there is limited research on the potential connection between work shifts and abnormal serum uric acid (SUA) levels. Furthermore, the factors that contribute to abnormal SUA levels in shift workers are not well-understood. Therefore, this study aimed to analyze the SUA levels of shift workers employed in an aircraft maintenance company, investigate the potential association between shift work and SUA levels, and explore the factors that may influence abnormal SUA levels in shift workers. METHODS: A total of 2263 male workers from an aircraft maintenance company were included in this study using the cluster sampling method. The workers were divided into two groups based on their working shifts: night shift (N = 1047, 46.27%) and day working (N = 1216, 53.73%). A survey was conducted between April 1st and June 30th, 2022 to gather information on work, lifestyle, physical examination results, and other relevant factors. The survey included a self-designed demographic information questionnaire to collect data on workers' characteristics, medical history, years of employment, smoking and drinking habits, and main lifestyle behaviors. The workers' SUA levels were measured using uricase colorimetry. One-way ANOVA was used to compare the difference in the abnormal detection rate of SUA between the two groups, and multi-factor logistic regression analysis was used to identify the factors that influence abnormal SUA levels. RESULTS: The study indicated that 48.9% of night shift workers and 43.8% in the regular day workers had abnormal SUA levels, with a significant difference between the two groups (χ2 = 6.125, P = 0.013). Factors such as circadian rhythm type, shift work, age, the taste of diet, type of diet, smoking, overweight or obesity based on body mass index (BMI), concentration of urine creatinine (CREA), total cholesterol, triglyceride, and low-density lipoprotein cholesterol were found to be correlated with SUA abnormalities (P < 0.05). The risk of developing SUA abnormalities was found to be higher in individuals with an intermittent (OR = 1.34, 95% CI: 0.83-2.12, P < 0.05) or evening circadian rhythm type (OR = 1.45, 95% CI: 0.86-2.43, P > 0.05) compared to those with a morning type. Additionally, factors such as night shift work, a high-sodium diet, smoking, a diet high in meat and low in vegetables, being overweight or obese, and higher levels of CREA were also found to increase the risk of developing SUA abnormalities. The study also revealed a significant dose-response relationship between BMI and abnormal uric acid levels. After controlling for other factors, the risk of developing SUA abnormalities was found to be 1.18 times higher in the night shift work group than in the day work group (OR = 1.18, 95% CI:1.02-1.34, P = 0.01). CONCLUSION: Shift work has been linked to a higher risk of developing SUA abnormalities, and there are several factors that may contribute to this risk. To prevent diseases, it is recommended that enterprises implement better health monitoring and management practices for shift workers.

Shift work effects on incident neuropsychiatric disorders and shift work tolerance.

BACKGROUND: Shift work is associated with susceptibility to several neuropsychiatric disorders. This study aims to investigate the effect of shift work on the incidence of neuropsychiatric disorders, and highlighting how individual variability may influence the association. METHODS: UK Biobank participants with employment information were included. Cox survival was conducted in main and subgroup analyses. Correlation analyses explored the impact of shift work on brain structures, and mediation analyses were performed to elucidate the shared underlying mechanisms. Shift work tolerance was evaluated through survival analyses contrasting the risks associated with five neuropsychiatric disorders in shift versus non-shift workers across different demographic or occupational strata. RESULTS: The analysis encompassed 254,646 participants. Shift work was associated with higher risk of dementia (HR 1.29, 95 % CI 1.10-1.52), anxiety (1.08, 1.01-1.15), depression (1.29, 1.22-1.36), and sleep disorders (1.18, 1.09-1.28), but not stroke (p = 0.20). Shift work was correlated with decreasing volume of various brain regions, particularly in thalamus, lateral orbitofrontal, and middle temporal. Mediation analysis revealed that increased immune response and glucose levels are common pathways linking shift work to these disorders. We observed diversity in shift work tolerance across different individual characteristics, among which socioeconomic status and length of working hours were the most essential. LIMITATIONS: Self-reported employment information may cause misclassification and recall bias. And since we focused on the middle-aged population, the conclusions may not be representative of younger or older populations. CONCLUSIONS: Our findings indicated the need to monitor shift worker health and provide personalized management to help adapt to shift work.

Dietary Rhythmicity and Mental Health Among Airline Personnel.

Importance: Misaligned dietary rhythmicity has been associated with metabolic diseases; however, its association with mental health remains largely unexplored. Objective: To examine the association between dietary rhythms and the mental health condition of shift workers, specifically airline crew members. Design, Setting, and Participants: This cross-sectional study analyzed data collected from the Civil Aviation Health Cohort of China, an ongoing large-scale health survey of pilots, flight attendants, and air security officers employed by major airline companies in China. Participants aged 18 to 60 years were invited through text messages to complete a web-based survey. The data collection period was December 2022 to March 2023. Statistical analysis was performed from July 24, 2023, to April 12, 2024. Exposure: Data on timing of breakfast and dinner on workdays and rest days, daily time windows for food intake, and meal and eating jet lags were collected and calculated. Main Outcomes and Measures: Anxiety and depressive symptoms were measured using the 7-item Generalized Anxiety Disorder Assessment and the 9-item Patient Health Questionnaire. Multivariate logistic regressions were performed to evaluate the associations of anxiety and depression with meal timing, eating window time, meal jet lag (ie, delayed meals), and eating jet lag (ie, delayed eating). All models were adjusted for individual socioeconomic, demographic, and lifestyle characteristics. Results: Of the 22 617 participants (median [IQR] age, 29.1 [26.3-33.7] years; 13 712 males [60.6%]), 1755 (7.8%) had anxiety and 2768 (12.2%) had depression. After controlling for confounding factors, having dinner after 8 pm on morning-shift days was associated with increased odds of anxiety (adjusted odds ratio [AOR], 1.78; 95% CI, 1.53-2.05) and depression (AOR, 2.01; 95% CI, 1.78-2.27), compared with consuming dinner before 8 pm. Similar results were observed on night-shift days and rest days. An eating window of less than 12 hours was associated with reduced odds of anxiety (AOR, 0.84; 95% CI, 0.75-0.93) and depression (AOR, 0.81; 95% CI, 0.75-0.89) on morning-shift days; the results remained significant on rest days. Delayed dinner on morning-shift days was associated with increased odds of anxiety (AOR, 1.32; 95% CI, 1.13-1.54) and depression (AOR, 1.39; 95% CI, 1.22-1.58). On night-shift days, delayed dinner was associated with higher odds of anxiety (AOR, 1.22; 95% CI, 1.06-1.39) and depression (AOR, 1.21; 95% CI, 1.08-1.36). On morning-shift days, delayed eating rhythms were associated with higher odds of depression (AOR, 1.35; 95% CI, 1.13-1.61), whereas advanced eating rhythms were associated with lower odds of anxiety (AOR, 0.78; 95% CI, 0.70-0.87). Conclusions and Relevance: This cross-sectional study found that meal timing, long eating window, and meal jet lags were associated with increased odds of depression and anxiety. These findings underscore the need for interventions and supportive policies that help mitigate the adverse implications of shift work and irregular working hours for the mental health of shift workers.