Sleep Duration Modifies the Association of Overtime Work With Risk of Developing Type 2 Diabetes: Japan Epidemiology Collaboration on Occupational Health Study

Relationship of personal, situational, and environmental factors to injury experience in commercial fishing

INTRODUCTION

Commercial fishing work involves a variety of activities and is hazardous. While much is understood to mitigate fatalities in this industry, research must further explore nonfatal injury characteristics, factors related to injury, and potential injury prevention strategies. This paper determines if fishing experience is associated with injury risk and explores common work activities associated with injury.

METHOD

Key informant interviews and a survey of fishermen were conducted to refine work activity codes and collect injury experiences. Independent sample t-tests compared the means of the years fishing by injury incident for all crab fishermen then stratified by position. Descriptive statistics explored the nature of injury in relation to work activity.

RESULTS

The level of experience was significantly lower for injured fishermen compared to fishermen who reported no injuries, but when stratified by position at the time of the injury, the association of injury to experience was only significant for owners. This stratified result demonstrates that the work activity, rather than experience, drives the apparent relationship of experience to injury. Being tired (24%) and weather (26%) were indicated as contributing factors at the time of injury.

CONCLUSION

Modifying the work environment to better control hazards would benefit all fishermen, regardless of their experience, age, or position. Further work into effective interventions that fishermen would adopt is needed to reduce injury risk. Any formal or informal training of new fishermen should focus on the most hazardous activities, but more experienced fishermen would also benefit. Additionally, effective training or interventions for fatigue management, and decision support tools for weather- and navigation-related decisions would further reduce risk of at sea injuries.

PRACTICAL APPLICATIONS

Injury prevention training, for all fishermen, regardless of their position and years of experience, should cover the most hazardous tasks, fatigue risk management strategies, and weather decisions.

Assessment of sex differences in associations between sleep duration and lipid/glucose metabolism in urban Japan: a cross-sectional study

Inadequate sleep durations (short or long) are related to worsening of lipid/glucose metabolism, leading to atherosclerotic cardiovascular diseases (ASCVD). Few data exist on sex differences in this relationship that, to date, has been scarcely reported. This cross-sectional study included 6678 men and 4700 women at the Health Planning Center of Nihon University Hospital, located in the center of Tokyo, between September 2015 and October 2016. The prevalence of diabetes and dyslipidemia in the participants was 3.3% and 6.5%, respectively. Sleep duration was divided into five categories: < 5 h, 5-6 h, 6-7 h, 7-8 h, and ≥ 8 h. We examined the odds ratio (OR) and 95% confidence interval (CI) of lipid/glucose metabolism-related markers for the reference value defined in each guideline with 6-7 h as the reference of comparison. In men, a sleep duration of < 5 h was associated with ORs of 1.32 and 1.33 (95% CI, 1.01-1.73 and 1.02-1.74) for LDL-C level ≥ 120 mg/dL and non-HDL-C level of ≥ 150 mg/dL (defined as "borderline hyper" by the Japan Atherosclerosis Society Guidelines for Prevention of ASCVD 2017), respectively. Moreover, a sleep duration of < 5 h was associated with an OR of 1.77 (1.33-2.35) for fasting blood glucose of ≥ 100 mg/dL (defined as "high" by a specialized lifestyle checkup program in Japan). In women, sleep duration of < 5 h was associated with an OR of 1.70 (1.24-2.33) for HbA1c level of ≥ 5.6% (defined as "high" by a specialized life style checkup program in Japan). However, there was no association between sleep duration and serum lipid profile. Inadequate short sleep duration was as a potential risk factor of adverse lipid and/or glucose metabolism in both sexes. However, there were sex differences in associations between sleep duration and lipid/glucose metabolism in urban Japan. To further reduce risks of ASCVD, it is of particular importance to emphasize adequate sleep duration in both sexes.Trial registration UMIN ( http://www.umin.ac.jp/ ) Study ID: UMIN000037643 retrospectively registered on August 9, 2019.

Overtime Work and the Incidence of Long-term Sickness Absence Due to Mental Disorders: A Prospective Cohort Study

Background

Methods

Results

Conclusion

Association Between Psychological Distress and Stress-Related Symptoms and Increased Risk of Type 2 Diabetes in Male Individuals: An Observational Study

Background

This study evaluated the association between psychological distress and development of type 2 diabetes (T2D) among male individuals in the workplace.

Methods

This observational cohort study enrolled 6,326 male participants aged 18 - 65 years (mean age 47.4 ± 9.5 years, body mass index 23.4 ± 3.4 kg/m², hemoglobin A1c 5.5±0.3%), who received annual health checkups from April 2016 to March 2017. Those who had a hemoglobin A1c level ≥ 6.5%, previous history of diabetes, or used diabetes medication were excluded from the analysis. Psychological distress was measured using the Brief Job Stress Questionnaire. Multivariate Cox proportional hazard regression models were used to estimate the development of T2D in relation to psychological distress and stress-related symptoms. The calculated hazard ratio (aHR) was adjusted for age, body mass index, and hemoglobin A1c level.

Results

During a mean follow-up period of 1.9 years, the incidence rate of new-onset T2D was 2.0%. Baseline psychological parameters did not differ between participants with or without new-onset T2D. Depression was associated with an increased risk of T2D (aHR = 1.54, 95% confidence interval (CI): 1.07 - 2.22), whereas vigor, irritation, fatigue, and anxiety were not. Moreover, inability to handle work (aHR = 2.18, 95% CI: 1.14 - 4.19), sadness (aHR = 1.93, 95% CI: 1.14 - 3.26), headache (aHR = 1.98, 95% CI: 1.18 - 3.34), shoulder stiffness (aHR = 1.56, 95% CI: 1.10 - 2.23), and constipation/diarrhea (aHR = 1.71, 95% CI: 1.04 - 2.80) were associated with T2D incidence.

Conclusions

Depression and stress-related symptoms were associated with an increased risk of T2D. Industrial physicians and health care providers should evaluate these factors during health checkups to lower the T2D incidence in this population

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

OBJECTIVE

To 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.

DESIGN

A cross-sectional observational study.

SETTING

A healthcare examination centre in Japan.

PARTICIPANTS

Between 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/m² and full-time workers.

EXPOSURE

Night and shift (night/shift) workers were compared with daytime workers in terms of motivation for behavioural change.

PRIMARY AND SECONDARY OUTCOME MEASURES

The 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.

RESULTS

Overall, 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).

CONCLUSIONS

In 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.

Patterns of changes in overtime working hours over 3 years and the risk for progression to type 2 diabetes in adults with pre-diabetes

No information exists regarding the effects of working hours on glucose metabolism in adults with pre-diabetes, a high-risk group for developing diabetes. Further, longitudinal patterns in working hours and their effects on glucose metabolism have not been described previously. We investigated the association between changes in overtime working hours over 3 years and the risk for progression to type 2 diabetes among adults with pre-diabetes. We analyzed patterns of overtime working hours from 2008 to 2011 among 18,172 workers in Japan (16,474 men, aged 30 to 64 years) with pre-diabetes in 2011 (baseline) using the sub-cohort data from the Japan Epidemiology Collaboration on Occupational Health Study. Participants were followed up to March 2016. Overtime working hours per month were self-reported annually in 2008-2011 and trajectory patterns were identified using group-based trajectory modeling. Type 2 diabetes was diagnosed by fasting or random plasma glucose test, hemoglobin A1c, and history of diabetes. Multivariable-adjusted hazard ratios of incident diabetes were calculated using Cox regression. We identified 3 distinct trajectories of overtime work: persistently short, long-to-short, and persistently long. During a mean follow-up of 3.5 years, 1613 participants (8.9%) developed diabetes. Compared with persistently short overtime working hours, no material increase in diabetes risk was observed for either long-to-short working hours or persistently long working hours. After adjustment for potential confounders, this association was materially unchanged. The results suggest that among individuals with pre-diabetes, persistently long working hours over 3 years were not associated with an increased risk of developing type 2 diabetes.