Associations of occupation categories with cardiovascular diseases and all-cause mortality: an analysis of NHANES 2005-2014

BACKGROUND

Evidence on the effects of occupation categories on cardiovascular disease (CVD) progression and longevity has mostly come from cross-sectional studies, which limits our understanding of the pathogenesis of CVD. This study aimed to evaluate the associations of occupation categories with CVD and all-cause mortality in the American population.

METHODS

We analyzed data from the 2005-2014 U.S. National Health and Nutrition Examination Survey (NHANES), a large-scale public health survey representative of the U.S. population, linked to mortality data obtained in 2019. To evaluate the association between occupation categories and the risks of cardiovascular disease (CVD) and all-cause mortality, we estimated Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Among 11,102 participants (aged 20-85 years, 53.99% male), 132 died from CVD among the total 478 deaths during a median follow-up of 9.9 years. In multivariable-adjusted models, the occupation categories were significantly associated with CVD mortality, with the hazard ratios (HRs) and 95% confidence intervals (95% CIs) of 3.95(1.94-8.04) for construction and clean-up industry, 2.51(1.15-5.52) for sales and service industry, 2.49(1.04-5.95) for business and management, and 2.98(1.56,5.71) for others. For all-cause mortality, only construction and clean-up industry and sales and service industry were positively associated with all-cause mortality, and HRs (95% CIs) were 2.05(1.33-3.16) and 1.64(1.12-2.41). Both working hours in the previous week and the number of months worked exhibited varying degrees of dose-response relationships with CVD and all-cause mortality.

CONCLUSIONS

Occupation categories were found to be significantly associated with the risk of CVD and all-cause mortality. Future research could incorporate different work properties into specific prevention strategies for these outcomes.

Trajectories of working hours in later careers and their association with social and health-related factors: a follow-up study

BACKGROUND

The aim was to identify working hours' trajectories in later work careers over a follow-up of 15-17 years and to examine their association with social factors and health.

METHODS

A subsample from the Helsinki Health Study was extracted comprising employees of the City of Helsinki, Finland. Growth mixture modelling was used to identify different working hour trajectories. Age, gender, occupational class, marital status, health behaviour, physical and mental functioning and current pain were associated with trajectory membership. Relative risks (RRs) and their 95% confidence intervals (CIs) were estimated.

RESULTS

A two-trajectory model was selected: 'Stable regular working hours' (90%) and 'Shorter and varying working hours' (10%). Women (RR 1.40, 95% CI 1.09-1.78), the oldest employees (RR 2.71, 95% CI 2.06-3.57), managers and professionals (RR 1.56, 95% CI 1.20-2.02), those reporting non-drinker (RR 1.66, 95% CI 1.32-2.10), those reporting sleeping more than 8 h per night (RR 1.74 95% CI 1.25-2.42) and those reporting poor mental functioning (RR 1.39 95% CI 1.15-1.68) had higher likelihood of belonging to the trajectory 'Shorter and varying working hours'. There were no differences between the trajectories in marital status, smoking, body mass index, current pain or physical functioning. However, routine non-manual workers (RR 0.74, 95% CI 0.55-0.98), and semi-professionals (RR 0.70, 95% CI 0.50-0.96) had lower likelihood of belonging to this trajectory.

CONCLUSIONS

Trajectories of working hours in later work career differ by age, gender and occupational class but also by health behaviours and mental health functioning.

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.

A meta-analysis of observational studies including dose-response relationship between long working hours and risk of obesity

We aimed to conduct a meta-analysis with stick reference and uniform cut-off of obesity to evaluate the relationship between long working hours and risk of obesity, using a quantitative dose-response method. The PubMed and Web of Science databases were searched through February 26, 2021, odds ratios (ORs) were pooled by using random-effects models and restricted cubic spline analysis with four knots was used to explore the dose-response relationship of working time and risk of obesity. Ten observational studies with 20 independent reports involving 189,590 participants were included in the present analysis. The summarized adjusted OR for the relationship between long working hours and obesity risk was 1.13 (95% CI: 1.01 to 1.26), when compared with weekly working hours less than and equal to 40 h using the random-effects model. A J-shaped association between long working hours and risk of obesity was observed (P < 0.001 for nonlinearity) for the dose-response relationship. Exclusion of any single study did not alter the combined relative risk. Individuals involved in long working hours are more likely to be obesity. Further studies are needed to confirm the results, and optimized and proper job arrangement should be established for improving the health of workers.

Lifetime high occupational physical activity and total and cause-specific mortality among 320 000 adults in the NIH-AARP study: a cohort study

OBJECTIVES

We examined the associations of history and duration in high occupational physical activity (OPA) with long-term total and cause-specific mortality.

METHODS

The sample included 322 126 participants (135 254 women) from the National Institutes of Health-AARP Diet and Health Study, established in 1995-1996. History and duration in high OPA were reported by participants. All-cause, cardiovascular, cancer and other cause mortality records available through 31 December 2011.

RESULTS

The prevalence of high OPA was 52.1% in men and 16.1% in women. During 13.6 years (SD, 3.3) of follow-up, 73 563 participants (25 219 women) died. In age-adjusted models, the risk of death was higher among men (HR 1.14, 95% CI 1.12 to 1.16) and women (HR 1.22, 95% CI 1.18 to 1.26) with a history of high OPA. However, these associations were substantially attenuated in women (HR 1.04, 95% CI 1.00 to 1.07, an 81.8% attenuation) and eliminated in men (HR 1.02, 95% CI 0.99 to 1.04, 85.7% attenuation) after multivariable adjustments. Similar important attenuation results were found when examining duration in high OPA, as well as using cause-specific deaths as the outcomes. Educational attainment and smoking patterns were the main contributors in the excess mortality among people working in highly physically active jobs in both men and women.

CONCLUSION

Participating in high OPA was not consistently associated with a higher mortality risk, after adjustments for education and smoking factors. Workers in high OPA should be aware that they might not be getting all well-known health benefits of being physically active if they are only very active at work.

Does an increase in working hours affect mortality risk? The relationship between working hours and mortality among the older population

BACKGROUND

Population aging, caused by an increase in life expectancy and decrease in fertility rates, has created changes and challenges in various spheres, including the labor market. Though health deteriorates with age, more and more older adults choose to stay in the labor force and work into late life.

OBJECTIVE

Understanding the effects of various work conditions on the health of older workers is crucial for designing policies and interventions to ensure healthy late life and maintain a productive workforce. To contribute to this endeavor, this study investigates the relationship between long working hours (LWH) and mortality among older populations.

METHODS

The study uses the Cox proportional hazards regression model to investigate data from the Health and Retirement Survey (HRS) between the years 1992-2016, a longitudinal nationally representative dataset from the United States.

RESULTS

The results indicate that working 50 hours or more per week is not associated with an increased risk of mortality, for the full sample (1.45 [95% CI: 0.86, 2.45]), for both genders (females 0.51 [95% CI: 0.06, 4.28], males 1.45 [95% CI: 0.81, 2.61]), and for immigrants (female immigrants 0.55 [95% CI: 0.06, 4.75], male immigrants 1.44 [95% CI: 0.79, 2.62]).

CONCLUSIONS

This analysis confirms and extends the findings of earlier studies by taking into consideration the potential impact of many demographic, socioeconomic, work-related and health-related factors.

Long working hours and psychiatric treatment: A Danish follow-up study

Objective:

This study aimed to estimate prospective associations between long working hours and (i) redeemed prescriptions for psychotropic drugs and (ii) psychiatric hospital treatment due to mood, anxiety or stress-related disease, among full-time employees in Denmark.

Methods:

Full-time employees who participated in the Danish Labor Force Survey sometime in the period 2000–2013 (N=131 321] were followed for up to five years in national registers for redeemed prescriptions for psychotropic drugs and psychiatric hospital treatment due to mood, anxiety or stress-related disease. Rate ratios (RR) were estimated for 41–48 versus 32–40 and >48 versus 32–40 working hours a week. The analyses were controlled for sex, age, night shift work, calendar time of the interview and socioeconomic status (SES). Prevalent cases were excluded in primary analyses.

Results:

The RR for psychotropic drugs were estimated at 0.94 [99% confidence interval (CI) 0.88–1.01] for 41–48 versus 32–40 working hours a week and 1.08 (99% CI 0.99–1.18) for >48 versus 32–40 working hours a week. The corresponding RR for psychiatric hospital treatments were estimated at 0.90 (95% CI 0.75–1.08) and 0.96 (95% CI 0.76–1.21). We did not find any statistically significant interaction between weekly working hours and age, sex, SES or night shift work.

Conclusion:

Long working hours as they occur in in the general working population of Denmark are not an important predictor of mental ill health.

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.

Lifestyle-Related Factors and Total Mortality in a Mediterranean Prospective Cohort

INTRODUCTION

Lifestyle-related habits have a strong influence on morbidity and mortality worldwide. This study investigates the association between a multidimensional healthy lifestyle score and all-cause mortality risk, including in the score some less-studied lifestyle-related factors.

METHODS

Participants (n=20,094) of the Seguimiento Universidad de Navarra cohort were followed up from 1999 to 2018. The analysis was conducted in 2019. A 10-point healthy lifestyle score previously associated with a lower risk of major cardiovascular events was applied, assigning 1 point to each of the following items: never smoking, moderate-to-high physical activity, moderate-to-high Mediterranean diet adherence, healthy BMI, moderate alcohol consumption, avoidance of binge drinking, low TV exposure, short afternoon nap, time spent with friends, and working ≥40 hours per week.

RESULTS

During a median follow-up of 10.8 years, 407 deaths were documented. In the multivariable adjusted analysis, the highest category of adherence to the score (7-10 points) showed a 60% lower risk of all-cause mortality than the lowest category (0-3 points) (hazard ratio=0.40, 95% CI=0.27, 0.60, p<0.001 for trend). In analyses of the healthy lifestyle score as a continuous variable, for each additional point in the score, a 18% relatively lower risk of all-cause mortality was observed (adjusted hazard ratio=0.82, 95% CI=0.76, 0.88).

CONCLUSIONS

Adherence to a healthy lifestyle score, including some less-studied lifestyle-related factors, was longitudinally associated with a substantially lower mortality rate in a Mediterranean cohort. Comprehensive health promotion should be a public health priority.

Prospective Associations Between Working Time Arrangements and Psychiatric Treatment in Denmark: Protocol for a Cohort Study

BACKGROUND

The burden of mental ill health in working-age populations has prompted research on possible links between work-related factors and mental ill health. Long working hours and night shift work are some of the factors that have been studied in relation to the risk of developing mental ill health. Yet, previous studies have not generated conclusive evidence, and further studies of high quality are needed.

OBJECTIVE

This study aims to investigate the prospective association between working time arrangements and mental health in terms of psychotropic drug usage or psychiatric hospital treatment in the general working population of Denmark.

METHODS

Data on total weekly working hours in any job and night shift work from the Danish Labor Force Survey 2000-2013 will be linked to data from the Psychiatric Central Research Register (expected 2400 cases during 700,000 person years at risk) and National Prescription Registry (expected 17,400 cases during 600,000 person years at risk). Participants will be followed for up to 5 years. We will use Poisson regression to separately analyze incidence rates of redeemed prescriptions for psychotropic medicine and incidence rates of psychiatric hospital treatment due to mood disorders, anxiety disorders, or stress-related disorders as a function of weekly working hours and night shift work. The analyses will be controlled for sex, age, calendar time of the interview, and socioeconomic status.

RESULTS

This is a study protocol. Power calculations indicate that the study has sufficient statistical power to detect relatively small differences in risks and minor interactions (eg, ~90% power to detect a rate ratio of 1.1 for psychoactive medication use). We expect the analyses to be completed by the end of 2020 and the results to be published in 2021.

CONCLUSIONS

In this study protocol, all hypotheses and statistical models of the project have been completely defined before we link the exposure data to the outcome data. The results of the project will indicate to what extent and in what direction the national burden of mental ill health in Denmark has been influenced by long working hours and night shift work.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18236.

Long working hours and cardiovascular mortality: a census-based cohort study

OBJECTIVES

Long working hours have been associated with cardiovascular disease (CVD) mortality. However, results are inconsistent and large cohort studies are needed to confirm these findings.

METHODS

We conducted a census-based cohort study including 11,903,540 Italian workers aged 20-64 years, registered in the 2011 census, with a 5-year follow-up (2012-2016). We estimated cause-specific hazard ratios (cHRs) through Cox regression models to quantify the association between long working hours and CVD mortality.

RESULTS

Over 5 years of follow-up, 17,206 individuals died from CVD (15,262 men and 1944 women). Men working 55 or more hours per week had a cHR of 0.95 (95% confidence interval, CI 0.89-1.02) for all CVDs, while women showed a cHR of 1.19 (95% CI 0.95-1.49). Professional women working more than 55 h per week had a cHR of 1.98 (95% CI 0.87-4.52).

CONCLUSIONS

This study does not support an association between long working hours and CVD mortality among active Italian men, while it suggests a possible excess risk among women, although based on limited number of events.

Working hour characteristics and schedules among nurses in three Nordic countries - a comparative study using payroll data

Background

Organisation of working hour schedules in the Northern European countries are rather similar. EU countries are obliged to adopt national legislation regarding duration of weekly working hours and rest periods. Yet, working hour characteristics and schedules are likely to differ with respect to starting times and duration depending e.g. on culture and tradition. Yet, very little is known about potential differences between shifts and schedules across countries among nursing personel. This knowledge is relevant, since the potential differences in working hour characteristics may influence and possibly explain some of the differences observed in studies of health and safety.The aim of the study was to compare characteristics of working hours and work schedules among nursing personel in three Nordic countries: Denmark, Finland and Norway.

Methods

The study populations included nursing personnel holding a ≥ 50% position at public hospitals in Denmark (n = 63,678), Finland (n = 18,257) or Norway (n = 1538) in 2013. Objective payroll based registry data with information on daily starting and ending times were used to compare working hour characteristics e.g. starting time, duration of shift, and quick returns (< 11 h between two shifts), as well as work schedules e.g. permanent or 3-shift work between the three countries.

Results

Night shifts generally started earlier and lasted longer in Finland (10-11 h starting at 20:00-22:59) than in Norway (10 h starting at 21:00-21:59) and in Denmark (8 h starting at 23:00-23:59). Very long shifts (≥12 h) were more common in Denmark (12%) compared to Finland (8%) and Norway (3%). More employees had many (> 13/year) quick returns in Norway (64%) and Finland (47%) compared to Denmark (16%). The frequency of 3-shift rotation workers was highest in Norway (41%) and lower in Denmark (22%) and Finland (22%). There were few differences across the countries in terms of early morning shifts and (very) long weekly working hours.

Conclusion

Despite similar distribution of operational hours among nurses in the three countries, there were differences in working hour characteristics and the use of different types of work schedules. The observed differences may affect health and safety.

Night-time work and all-cause mortality in the general working population of Denmark

PURPOSE

A recent study among female nurses in Denmark found an increased mortality among night-time workers, which has raised concerns about the sufficiency of the EU Working Time Directive. The aim of the present study was to examine the relationship between night-time work and all-cause mortality among full-time employees in the general workforce of Denmark.

METHODS

Interview data from the Danish Labour Force Surveys, 1999-2013, were linked to national registers with individual-level data on occupation, industry, socioeconomic status (SES), emigrations and deaths. The participants (N = 159,933) were followed from the end of the calendar year of the interview until the end of 2014. Poisson regression was used to estimate rate ratios for all-cause mortality, with and without stratification by sex and socioeconomic status. A likelihood ratio test was used to test the overall null-hypothesis, which stated that the mortality rates were independent of night-time work, SES × night-time work and sex × night-time work.

RESULTS

The likelihood ratio test did not reject the null hypothesis (p = 0.14). The rate ratio for all-cause mortality among employees with vs. without night-time work was estimated at 1.07 (95% CI 0.97-1.19) after adjustment for age, sex, SES, calendar time, weekly working hours and time passed since the start of follow-up.

CONCLUSIONS

The present study did not find any statistically significant associations between night-time work and all-cause mortality among employees in the general workforce of Denmark.