Long working hours directly and indirectly (via short sleep duration) induce headache even in healthy white-collar men: cross-sectional and 1-year follow-up analyses

Changes in work schedule affect headache frequency among Norwegian nurses: a 3-year-follow-up study

OBJECTIVES

To explore whether changes in work schedule, number of night shifts and number of quick returns were related to changes in headache frequencies.

METHODS

A longitudinal study with questionnaire data from 2014 (baseline) and 2017 (follow-up) on work schedule (day only, shift work without nights and shift work with nights), number of night shifts, number of quick returns (less than 11 hours in-between shifts) and validated headache diagnoses among 1104 Norwegian nurses. Associations were explored by adjusted multivariate regression analyses.

RESULTS

The median age at baseline was 37 years (IQR 31-43) and 90.5% were women. In the adjusted logistic regression analysis of changed work schedule between baseline and follow-up, changing from night work was associated with increased odds for reversion from headache >1 days/month to no headache at all last year (OR 2.77 (1.29; 5.95)). Changes towards less night shifts (>10) or quick returns (>10) during the last year were associated with increased odds of reversion of headache to no headache (OR 2.23 (1.20; 4.17) and OR 1.90 (1.04; 3.49)). Only decrease in number of night shifts (>10) during the last year reduced risk of onset of any new headache between baseline and follow-up (OR of 0.39 (0.18; 0.84)).

CONCLUSION

Changing from night work and reducing the number of night shifts and quick returns were associated with less headache in this 3-year-follow-up of Norwegian nurses. This adds to the growing body of evidence that night work may have direct negative health consequences.

Inter-rater reliability, discriminatory and predictive validity of neck movement control tests in office workers with headache and/or neck pain

BACKGROUND

Movement control tests (MCTs) are clinical tests to evaluate impairment of movement and associated neuromuscular control and are commonly used to evaluate people with neck pain or headache conditions. The aim of this study was to establish inter-rater reliability as well as discriminatory and predictive validity for seven MCTs of the upper (UCS) and lower cervical spine (LCS) in office workers with headache or neck pain.

METHODS

Seven MCTs of the UCS (3) and LCS (4) were performed at baseline on 140 office workers which were included in a cluster randomized controlled trial. The occurrences of headache and neck pain were established at baseline (discriminatory validity) and at a 15-month follow-up (predictive validity). Inter-rater-reliability was established in a separate cross-sectional study.

RESULTS

MCTs showed slight to almost perfect inter-rater reliability but limited discriminatory (baseline) and limited to small predictive validity (15-month follow up) for different subgroups of office workers with headache and/or neck pain. MCTs of the UCS showed limited discriminatory validity, especially for rotation in participants with headache and neck pain compared to those with headache only (Negative Likelihood-ratio: 0.82, 95% CI: 0.69-0.98). Participants with neck pain only and ≥1/4 positive MCTs for the sagittal plane had an increased risk for future neck pain (Relative risk: 3.33, 95% CI: 1.05-10.56).

DISCUSSION

MCTs of the UCS and LCS are reliable but have only limited to small validity to predict future headache events in office workers. Insufficient sagittal plane movement control may predict neck pain relapses in the future.

Extended Work Shifts Increase Subjective Pain Complaints Among Cabin Crewmembers, but Not Among Airline Pilots or Healthcare Workers: A Repeated-Measures Study

OBJECTIVE

To determine whether four consecutive extended work shifts are associated with an increased risk of subjective pain complaints, sleep duration, and sleep disturbances.

METHODS

Forty-three healthcare workers, 41 cabin crewmembers, and 18 airline pilots working 4 consecutive extended workdays reported subjective pain complaints and sleep after the 1st and 4th workday.

RESULTS

The risk of headache (odds ratio [OR] 21.4, 95% confidence interval [CI] 1.85 to 246.5) and pain in the hands, arms, or wrists (OR 3.78, 95% CI 1.84 to 7.76) increased after workday 4 versus workday 1 in cabin crewmembers. Sleep duration was longer (0.6 to 1.1 hours), and sleep disturbances fewer, the night before the fourth extended workday, compared with before the first workday, in all occupations.

CONCLUSIONS

We found no general support for an association between extended work shifts and subjective pain, whereas sleep duration was improved, and sleep disturbances reduced after 4 consecutive extended workdays.

The Relationship Between Long Working Hours and Stress Responses in Junior High School Teachers: A Nationwide Survey in Japan

Background: Long working hours and mental health problems among teachers are a concern in Japan. More specifically, it has been reported that junior high school teachers tend to work overtime. In this study, examined the working hours of junior high school teachers in public schools and investigated the association between overtime work and stress responses across job titles.

Methods: From June to December 2018, 54,772 teachers in public junior high schools completed a web-based nationwide survey regarding occupational stress and submitted self-evaluated working hours per day of the previous month. Psychological and physical stress responses were assessed using the Brief Job Stress Questionnaire.

Results: Results showed that 59.6% of the participants worked 11 h or more per day. Additionally, the length of working hours significantly differed across job titles (χ² (30) = 5295.8, p < 0.001, Cramér’s V = 0.14). With respect to tenured teachers, sex (female), age, taking charge of the class, number of working years in the same school, working hours of 10 to 11 h, 11 to 12 h, 12 to 13 h, and 13 h or more were significantly associated with high stress, compared to those who worked less than 9 h per day. Moreover, for fixed-term teachers, sex (female), age, working hours of 9 to 10 h, 10 to 11 h, 11 to 12 h, 12 to 13 h, and 13 h or more were related with more stress as compared to those who worked less than 9 h per day. On the other hand, there was no significant relationship between long working hours and stress response among vice-principals, even though they tended to work the longest hours.

Conclusion: We verified that Japanese junior high school teachers work long hours. Long working hours were associated with stress responses in both tenured and fixed-term teachers, but not in vice-principals. However, vice-principals work the longest hours among teachers, and we suggest that these long working hours may be a hidden problem that is often overlooked.

Long working hours and risk of 50 health conditions and mortality outcomes: a multicohort study in four European countries

BACKGROUND

Studies on the association between long working hours and health have captured only a narrow range of outcomes (mainly cardiometabolic diseases and depression) and no outcome-wide studies on this topic are available. To achieve wider scope of potential harm, we examined long working hours as a risk factor for a wide range of disease and mortality endpoints.

METHODS

The data of this multicohort study were from two population cohorts from Finland (primary analysis, n=59 599) and nine cohorts (replication analysis, n=44 262) from Sweden, Denmark, and the UK, all part of the Individual-participant Meta-analysis in Working Populations (IPD-Work) consortium. Baseline-assessed long working hours (≥55 hours per week) were compared to standard working hours (35-40 h). Outcome measures with follow-up until age 65 years were 46 diseases that required hospital treatment or continuous pharmacotherapy, all-cause, and three cause-specific mortality endpoints, ascertained via linkage to national health and mortality registers.

FINDINGS

2747 (4·6%) participants in the primary cohorts and 3027 (6·8%) in the replication cohorts worked long hours. After adjustment for age, sex, and socioeconomic status, working long hours was associated with increased risk of cardiovascular death (hazard ratio 1·68; 95% confidence interval 1·08-2·61 in primary analysis and 1·52; 0·90-2·58 in replication analysis), infections (1·37; 1·13-1·67 and 1·45; 1·13-1·87), diabetes (1·18; 1·01-1·38 and 1·41; 0·98-2·02), injuries (1·22; 1·00-1·50 and 1·18; 0·98-1·18) and musculoskeletal disorders (1·15; 1·06-1·26 and 1·13; 1·00-1·27). Working long hours was not associated with all-cause mortality.

INTERPRETATION

Follow-up of 50 health outcomes in four European countries suggests that working long hours is associated with an elevated risk of early cardiovascular death and hospital-treated infections before age 65. Associations, albeit weak, were also observed with diabetes, musculoskeletal disorders and injuries. In these data working long hours was not related to elevated overall mortality.

FUNDING

NordForsk, the Medical Research Council, the National Institute on Aging, the Wellcome Trust, Academy of Finland, and Finnish Work Environment Fund.

The interplay of sleep duration, working hours, and obesity in Korean male workers: The 2010-2015 Korea National Health and Nutrition Examination Survey

The purpose of this study was to clarify the odds ratio for association between working hours and obesity in Korean male wage workers and investigate the role of sleep duration. This study is a cross-sectional one using large-scale national data from the Korea National Health and Nutrition Examination Survey collected between 2010 and 2015 to evaluate 2,592 male wage workers (between the ages of 19 and 60 years). Obesity was defined as 25kg/m² or more and working hours per week were categorized into <40, 40–49, 50–59, and ≥60 hours. Multiple regression analysis was performed to examine the odds ratio for association between working hours and obesity, after controlling for age, education, income, marital status, smoking, drinking, physical activity, daily energy intake, sleep duration, hypertension, diabetes, dyslipidemia, work schedule, and job category. Next, to study the mediating effect of sleep duration on the association between working hours and obesity, an analysis was performed using the Baron and Kenny method and the Sobel test. Results showed that workers with 50 to 59 hours had 1.4 times higher odds (odds ratio [OR] = 1.4, confidence interval [CI]: 1.11–1.85) of obesity and workers with 60 hours or more had 1.4 times higher odds (OR = 1.4, CI: 1.06–1.90) of obesity than workers with less than 40 hours. Sleep was found to have a mediating effect on the association between working time and body mass index. Therefore, the results of this analysis suggest that practitioners should identify potential factors such as working time and sleeping time when preventing work-related obesity.

Associations among working hours, sleep duration, self-rated health, and health-related quality of life in Korean men

BACKGROUND

This study aimed to examine the relationship between working hours and health-related quality of life (HRQOL) in men and to determine whether this relationship was mediated by sleep duration and self-rated health (SRH).

MATERIALS AND METHODS

Our study population included 2141 working men aged 20 to 49 years old from the Korea National Health and Nutrition Examination Survey 2016-2017. Working hours, SRH, and HRQOL were measured by a structured questionnaire survey. Sleep duration was calculated based on self-reported data. We investigated the association between working hours and HRQOL and performed a mediation analysis to evaluate the contributions of sleep duration and poor SRH to this relationship.

RESULTS

This study identified a significant association between working hours and HRQOL. Long working hours directly and indirectly affected HRQOL through poor SRH. Men who overworked were more likely to report poor HRQOL due to worsened SRH. Poor SRH was responsible for 26.3% of this relationship. But sleep duration did not explain the relationship between working hours and HRQOL.

CONCLUSIONS

Working hours were directly associated with HRQOL in men. Furthermore, there was an indirect effect of working hours on HRQOL mediated by poorer SRH. An improved work-life balance is necessary to promote men's health and quality of life.

Relationships between insomnia, long working hours, and long commuting time among public school teachers in Japan: a nationwide cross-sectional diary study

OBJECTIVES

The present study aimed to clarify the prevalence and risk factors of insomnia among public school teachers in Japan by examining the relationships between working hours, commuting time, and insomnia. Time spent on work activities among teachers with insomnia was also investigated.

METHODS

This study was a secondary analysis of data obtained in a 2016 survey of working conditions among public elementary/junior high school teachers in Japan. A total of 11,390 teachers (women: 47.4%, average age: 42.2 ± 11.3 years) were selected for analysis. The relationships between working hours, commuting time, and insomnia were evaluated using a binomial logistic regression model. The primary outcome was insomnia, defined by a score of ≥6 on the Athens Insomnia Scale. Explanatory factors were working hours/week, commuting time/day, six subscales of occupational stress, age group, presence of children, type of job, type of the school, and the urbanicity of the school.

RESULTS

In total, 41.7% of men and 44.0% of women were classified into the insomnia group. The insomnia group spent more time preparing for lectures, and a significant association was observed between insomnia and long working hours and commuting time. Results of multivariate logistic regression analysis showed that long working hours, long commuting time, and urbanicity of the school were statistically significantly associated with insomnia.

CONCLUSIONS

Insomnia is common among public school teachers in Japan. Our findings suggest the importance of reducing the time spent on working to prevent insomnia.