Annual risk of long-term sickness absence due to musculoskeletal disorders across the lifespan and the role of physical activity and insomnia symptoms: the HUNT Study

BACKGROUND

The risk of long-term sickness absence due to musculoskeletal (MSK) disorders could be driven by sleep problems and physical inactivity. However, it is not well explored if these associations differ across the lifespan. The aim of this study was to describe the annual risk of long-term sickness absence due to MSK disorders throughout working life, according to insomnia symptoms and physical activity, in people with and without MSK pain.

METHODS

A total of 38,253 working-age individuals (20-62 years) with information on self-reported chronic MSK pain, physical activity, and insomnia symptoms in the third (2006-08) and/or fourth (2017-19) survey of the Norwegian HUNT Study were included. Annual sickness absence up to 5 years after participation was obtained from national registry data. Annual risk of long-term sickness absence due to MSK disorders were estimated as the proportion receiving medical benefits for ≥ 31 consecutive days each calendar year using a Poisson regression model. The model was fitted via generalized estimating equations to account for dependencies in observations and presented according to categories of chronic MSK pain combined with insomnia symptoms (yes, no) or physical activity level (inactive/low, moderate, high).

RESULTS

The average annual proportion with long-term sickness absence due to MSK disorders increased from 3.7% in women < 30 years to 11.3% in women ≥ 50 years, and from 2.7 to 7.1% among men in the same age groups. Annual risk of long-term sickness absence due to MSK disorders was greater among those reporting chronic MSK pain and who also suffered from insomnia symptoms compared to those without any of these conditions. This was particularly evident in age 30-39 and 40-49 years, where the co-occurrence of chronic MSK pain and insomnia symptoms was associated with a 4-fold increased risk of long-term sickness absence due to MSK disorders in women, and an almost 5-fold increased risk in men. The risk of sickness absence did not differ according to physical activity levels.

CONCLUSION

The annual risk of long-term sickness absence due to MSK disorders in working-age individuals was related to insomnia symptoms, especially among those aged 40 to 60 years, but not to physical activity.

The effect of parental pain, disability benefits and education on risk of long-term sick leave due to musculoskeletal disorders and the modifying effect of sleep and physical activity: the HUNT study

BACKGROUND

Family factors, sleep, and physical activity have previously been associated with risk of sick leave and disability benefits due to musculoskeletal disorders. However, how these factors act during adolescence and young adulthood is unclear. The aim of this study was to (i) examine if chronic pain, disability benefits and education in parents influence the risk of long-term sick leave due to musculoskeletal disorders in young adulthood, and (ii) to explore if offspring sleep problems and physical activity modify these effects.

METHODS

A population-based prospective study of 18,552 adolescents and young adults (≤ 30 years) in the Norwegian HUNT Study. Survey data was linked to national registry data on sick leave, disability benefits, family relations and educational attainment. We used Cox regression to estimate hazard ratio (HR) with 95% confidence interval (CI) for long-term (≥ 31 days) sick leave due to a musculoskeletal disorder in offspring associated with parental factors and the joint effect of parental factors and offspring lifestyle factors.

RESULTS

Parental chronic pain (HR 1.36, 95% CI 1.27-1.45), disability benefits (HR 1.41, 95% CI 1.33-1.48) and low educational attainment (HR 1.78, 95% CI 1.67-1.90) increased the risk of long-term sick leave due to musculoskeletal disorders among offspring. There was no strong evidence that sleep and physical activity modified these effects.

CONCLUSION

Chronic pain, disability benefit and low education in parents increased the risk of long-term sick leave due to musculoskeletal disorders among offspring, but these effects were not modified by offspring sleep problems or physical activity level. The findings suggest that efforts beyond individual lifestyle factors might be important as preventive measures.

Night Work and Sustainable Working Life-A Prospective Trajectory Analysis of Swedish Twins

The aim was to investigate the changes in sustainable working life over 10-13 years of follow-up and the effect of baseline night work. Data from the Swedish national registers were used to define sustainable working life. Survey data in the 1998-2003 "SALT" with 34,680 twins or in the 2004-2006 "STAGE" with 19,637 twins were utilized to assess night work at baseline. Group-based trajectory and multinomial regression models were applied. The results of the SALT cohort yielded five trajectory solutions: stable sustainable working life (40%), stable lack of sustainable working life (25%), later decreasingly sustainable working life (15%), increasingly sustainable working life (14%), and early decreasingly sustainable working life (7%). In the STAGE cohort, four trajectories were detected: stable sustainable working life (83%), decreasingly sustainable working life (7%), stable lack of sustainable working life (5%), and increasing sustainable working life (5%). Night work was associated with the decreasing or increasing sustainable working life in the trajectory groups. To conclude, the largest parts of both cohorts followed trajectories of stable sustainable working lives. Night work was associated with both the trajectories of decreasing and increasing sustainable working lives.

Association of Sleep Duration, Napping, and Sleep Patterns With Risk of Cardiovascular Diseases: A Nationwide Twin Study

Background

Although sleep disorders have been linked to cardiovascular diseases (CVDs), the association between sleep characteristics and CVDs remains inconclusive. We aimed to examine the association of nighttime sleep duration, daytime napping, and sleep patterns with CVDs and explore whether genetic and early‐life environmental factors account for this association.

Methods and Results

In the Swedish Twin Registry, 12 268 CVD‐free twin individuals (mean age=70.3 years) at baseline were followed up to 18 years to detect incident CVDs. Sleep duration, napping, and sleep patterns (assessed by sleep duration, chronotype, insomnia, snoring, and daytime sleepiness) were self‐reported at baseline. CVDs were ascertained through the Swedish National Patient Registry and the Cause of Death Register. Data were analyzed using a Cox model. In the multiadjusted Cox model, compared with 7 to 9 hours/night, the hazard ratios (HRs) of CVDs were 1.14 (95% CI, 1.01–1.28) for <7 hours/night and 1.10 (95% CI, 1.00–1.21) for ≥10 hours/night, respectively. Compared with no napping, napping 1 to 30 minutes (HR, 1.11 [95% CI, 1.03–1.18]) and >30 minutes (HR, 1.23 [95% CI, 1.14–1.33]) were related to CVDs. Furthermore, a poor sleep pattern was associated with CVDs (HR, 1.22 [95% CI, 1.05–1.41]). The co‐twin matched control analyses showed similar results as the unmatched analyses, and there was no significant interaction between sleep characteristics and zygosity (P values >0.05).

Conclusions

Short or long sleep (<7 or ≥10 hours/night), napping, and poor sleep patterns are associated with an increased CVD risk. Genetic and early‐life environmental factors may not account for the sleep–CVD association.

Impact of Decreased Night Work on Workers' Musculoskeletal Symptoms: A Quasi-Experimental Intervention Study

A possible association between night shift work and musculoskeletal disorder has been suggested. This study aimed to evaluate the impact of decreased night work on musculoskeletal pain. Difference-in-difference estimation was used to compare changes in musculoskeletal pain between shift workers (N = 122) and non-shift workers (N = 170) in a manufacturing company before and after the introduction of a new shift system eliminating overnight work. Musculoskeletal pain was measured by a questionnaire asking if workers had symptoms in specific body parts, including the neck, shoulder, arm/elbow, wrist/hand, back, and leg/foot, over the past year. Generalized estimating equation models were used to estimate changes in pre- versus post-intervention musculoskeletal pain rates between the treated and control group. In the difference-in-difference (DID) models, prevalence of musculoskeletal pain for shoulder (−10.3%), arm (−12.9%), all sites combined (−9.2%), and upper extremity combined (−14.8%) showed significant decreases from pre- to post-intervention among the treated group (shift workers) compared to the control group (non-shift workers) after controlling for age and weekly working hours. Decreasing night work was related to improvement in musculoskeletal pain in shift workers.

Night work for hospital nurses and sickness absence: a retrospective study using electronic rostering systems

There is conflicting evidence on the effect of night work on sickness absence. Most previous studies used self-reporting to identify shift patterns and measure levels of sickness absence. In contrast, this study used objective data from electronic rosters to explore the association of nurses' patterns of night work and sickness absence. This was a retrospective longitudinal study of nurse roster data from 32 general medical and surgical wards in a large acute hospital in England. We used data from 3 years and included both registered nurses and unregistered nursing assistants. We used generalized linear-mixed models to explore the association between night work and the subsequent occurrence of sickness absence. Of 601,282 shifts worked by 1944 nursing staff, 38,051 shifts were lost due to sickness absence. After controlling for potential confounders including proportion of long (≥12 h) shifts worked, proportion of overtime shifts, proportion of shifts worked in the past 7 days, and staff grade, we found that staff working more than 75% of their shifts in the past 7 days as night shifts were more likely to experience sickness absence (aOR = 1.12; 95% CI: 1.03-1.21), compared to staff working on day only schedules. Sub-group analysis found that an association between a high proportion of night shifts worked and long-term sickness (aOR = 1.31; 95% CI: 1.15-1.50), but not short-term sickness. Working high proportions of night shifts, likely representing permanent night work schedules, is associated with a higher risk of long-term sickness absence for nurses working in inpatient adult wards in acute hospitals. The higher sickness absence rates associated with permanent night shifts could result in additional costs or loss of productivity for hospitals. This study challenges the assumption that permanent night schedules maximize circadian adjustment and, therefore, reduce health problems.

Working time characteristics and long-term sickness absence among Danish and Finnish nurses: A register-based study

BACKGROUND

Working time regimes in Denmark and Finland share many similarities such as nursing personnel working in highly irregular shift systems. Yet, there are also differences for example in policy on when and how the employers are compensated for sickness absence.

OBJECTIVE

We aimed to investigate the association between different working hour characteristics and long-term sickness absence and whether these associations differed within various age groups in two large datasets of nursing personnel from Denmark and Finland.

DESIGN

Based on objective payroll data we used Poisson regression models to calculate incidence rate ratios with 95% confidence intervals to prospectively assess the risk of long-term sickness absence in relation to annual working hour characteristics. The analyses were adjusted for age, sex, short-term sickness absence, and weekly working hours.

SETTING(S)

Danish and Finnish nursing personnel.

PARTICIPANTS

31,729 Danish and 6970 Finnish nursing personnel with ≥ 0.5 Whole-Time Equivalent, registered in the database ≥ 1 year, 18-67 years of age with less than 30 days sickness absence in baseline year 2008.

METHODS

Working hour characteristics were assessed for 2008: time of day; day; evening; night. Duration of shift; long shifts (9-12 h); very long shifts (12-24 h); quick returns (< 11 h between two shifts); long weeks (> 40 h/week); very long weeks (> 48 h/week); and consecutive night shifts (≥ 5 night shifts). Long-term sickness absence was assessed as first incidence of 30 or more consecutive days off in 2009-2015.

RESULTS

The Danish data showed having evening work or five or more consecutive night shifts were associated with higher risk of long-term sickness absence. When excluding pregnant women, night work was also associated to higher risk of sickness absence. When stratifying on age groups, we observed a lower risk of sickness absence in the youngest age groups and a higher risk among the oldest. The Finnish results showed a higher risk of sickness absence when working nights, longs shifts, quick returns, and long work weeks. When stratifying on age groups, the results showed similar tendencies as the Danish.

CONCLUSIONS

The results show that the scheduling of working hours is likely to affect the risk of long-term sickness absence and that the risk differs in different age groups. No consistent picture was found for the results from Denmark and Finland. Differences may be due to contextual differences thus comparison of risk of sickness absence in relation to working hours between countries should be performed with caution. Tweetable abstract: A recent study from Denmark and Finland shows higher risk for long sickness absence among nurses with five or more consecutive night shifts.

Physical working conditions and subsequent disability retirement due to any cause, mental disorders and musculoskeletal diseases: does the risk vary by common mental disorders?

PURPOSE

Physical work exposures and common mental disorders (CMD) have been linked to increased risk of work disability, but their joint associations with disability retirement due to any cause, mental disorders or musculoskeletal diseases have not been examined.

METHODS

The data for exposures and covariates were from the Finnish Helsinki Health Study occupational cohort surveys in 2000-2002, 2007 and 2012. We used 12,458 observations from 6159 employees, who were 40-60 years old at baseline. CMD were measured by the General Health Questionnaire (GHQ-12, cut-off point 3+). Four self-reported work exposures (hazardous exposures, physical workload, computer and shift work) were combined with CMD and categorized as "neither", "work exposure only", "CMD only", and "both". Associations with register-based disability retirement were assessed with Cox proportional hazards models for sample survey data adjusting for confounders over 5-year follow-up. Additionally, synergy indices were calculated for the combined effects.

RESULTS

Those reporting CMD and high physical workload had a greater risk of disability retirement due to any cause (HR 4.26, 95% CI 3.60-5.03), mental disorders (HR 5.41, 95% CI 3.87-7.56), and musculoskeletal diseases (HR 4.46, 95% CI 3.49-5.71) when compared to those with neither. Synergy indices indicated that these associations were synergistic. Similar associations were observed for CMD and hazardous exposures, but not for combined exposures to CMD and computer or shift work.

CONCLUSIONS

Identification of mental health problems among employees in physically demanding jobs is important to support work ability and reduce the risk of premature exit from work due to disability.

Trajectories of mobility limitations over 24 years and their characterization by shift work and leisure-time physical activity in midlife

BACKGROUND

We aimed to investigate trajectories of mobility limitations (MLs) over a period of 24 years. In addition, we aimed to study how shift work and leisure-time physical activity (LTPA) in midlife predict assignment to MLs trajectories separately for those retired on statutory pensions (SPs) and on disability pensions (DPs).

METHODS

Subjects who responded MLs questionnaires (1985-2009, N = 3048) in Finnish Longitudinal Study on Aging Municipal Employees were included in this prospective cohort study. LTPA and shift work were measured during baseline. International Classification of Functioning was used to code MLs. Growth mixture modeling was used to identify the trajectories of MLs. Odds ratio (OR) and their 95% Confidence interval (CI) were assessed by using multinomial logistic regression.

RESULTS

We identified four trajectories of MLs, namely low persistent, low increasing, high decreasing and high persistent. Among the SP recipients, shift work with night shifts was associated with an increased risk (adjusted OR 1.49; 95% CI 1.03-2.14) of belonging to the high persistent MLs trajectory. The inactive LTPA (SP: OR 5.99, 95% CI 3.39-10.58, DP: OR 6.81, 95% CI 2.52-18.43) was similarly associated with high persistent MLs trajectory.

CONCLUSION

Nearly two-thirds of the people retired due to disability belonged to high MLs trajectory. High persistent MLs trajectory was associated with physical inactivity in midlife among those retired on SP and on DP. Shift work with night shift predicted high persistent MLs in SP strata. Active involvement in LTPA during midlife could be beneficial to spend MLs free later life.

Night work as a risk factor for future cause-specific disability pension: A prospective twin cohort study in Sweden

The objectives of the study were to investigate the associations between night work and disability pension (DP) due to all causes, cardiovascular (CVD), mental, and other diagnoses, adjusting for familial confounding. The material of the study included comprehensive survey data on 27 165 Swedish twins born in 1935-1958 that were linked with DP data for the survey period (1998-2003) to 2013. Night work was assessed as years of working nights at least every now and then, and categorized into not at all, 1-10 years and over 10 years. For statistical analyses, Cox proportional hazards regressions were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). The results of the study indicated that over 10 years duration of night work had an age- and sex-adjusted HR of 1.48 (95% CI 1.11-1.98) for DP due to CVD and 1-10 years of night work an HR of 1.28 (95% CI 1.06-1.55) for DP due to mental diagnoses, but attenuated when covariates were adjusted for. Both 1-10 years (HR 1.27, 95% CI 1.17-1.39) and >10 years of night work (HR 1.20, 95% CI 1.08-1.34) were associated with DP due to all causes and other diagnoses. These risks remained after adjusting for covariates. To conclude, even modest exposure in terms of duration of night work is a risk factor for all-cause DP, but also for DP due to mental and other diagnoses. The risk of DP due to CVD seems to be associated with longer (>10 years) periods of night work. All the associations between night work and DP seem to be influenced by various covariates.