Register-based data of psychosocial working conditions and occupational groups as predictors of disability pension due to musculoskeletal diagnoses: a prospective cohort study of 24,543 Swedish twins

Sequences of sickness absence, disability pension and unemployment four years before and five years after musculoskeletal diagnosis among Swedish twins

AIMS

To investigate sustainable working life via identification of time-related sequences of sickness absence (SA), disability pension (DP) and unemployment four years before and five years after the first musculoskeletal diagnosis in a Swedish twin cohort. Other aims were to account for familial confounding and to examine the associations between sequences and sociodemographic characteristics.

METHODS

Among 28,474 Swedish twins, the patterns of interruptions of working life four years before the first M00-M99 diagnosis (MSD) and five years after MSD diagnosis were investigated with a sequence analysis in a seven-element state space consisting of sustainable working life, unemployment >90 days, moderate SA/DP (30-179 days), almost full year of SA/DP (180-365 days), full year of SA/DP (⩾ 365 days), death, and old-age pension.

RESULTS

The six-cluster solution had the best fit to the data. Five clusters had varying patterns of interruptions of sustainable working life (Clusters 2-6, n = 537-1949 with SA/DP, unemployment, but also accounting death and old-age pension) compared with the largest cluster with primarily sustainable working life (n = 23,316). Age, sex and familial factors affected the likelihood of belonging to the clusters with SA/DP.

CONCLUSIONS

Most Swedish twins with or without MSD diagnosis have a sustainable working life, although MSD was both prevalent and a strong risk factor for belonging to the clusters with SA/DP. Thus, early prevention of MSD and prevention of recurrent or long sickness absences due to any cause would be merited while paying special attention to women also.

Contribution of age, gender and occupational group to the higher risk of disability retirement among Finnish public sector employees

BACKGROUND

The aim of this study was to examine the differences in disability retirement between public and private sector employees and to examine the contribution of age, gender and occupational group to the differences between the sectors.

METHODS

Our Finnish register data consisted of about two million non-retired men and women aged 30-62 years. Cox proportional hazard models were used to calculate hazard ratios for any, full and partial disability retirement in the public sector compared with the private sector.

RESULTS

The risk of any disability retirement was higher in the public sector than in the private sector in all occupational groups. The unadjusted hazard ratio ranged from 1.29 (95% CI 1.16-1.44) among teaching professionals to 2.25 (95% CI 1.95-2.58) among skilled agricultural, forestry and fishery workers. Adjustment for age and gender attenuated the differences between the sectors. After adjusting for age, gender and occupational group, the hazard ratio was 1.29 (95% CI 1.27-1.32) for any disability retirement and 2.02 (95% CI 1.96-2.08) for partial disability retirement, but there was no difference between the public sector and private sector employees for full disability retirement.

CONCLUSIONS

Adjustment of age and gender attenuated the higher risk of disability retirement in the public sector, while adjustment for occupational group widened the sector differences in any and full disability retirement. The risk of partial disability retirement was higher in all occupational groups in the public sector than in the private sector. For full disability retirement, the differences between the sectors were small or non-existent.

Job demands and job control and their associations with disability pension-a register-based cohort study of middle-aged and older Swedish workers

OBJECTIVES

Job demands and control at work and their combination, job strain, have been studied in relation to risk of disability pension (DP) previously. In the present study, based on registry data, we aimed to deepen the knowledge by analyzing major disease groups among the DPs, dose-response shape of the associations, and potential confounding effects of physical workload.

METHODS

Approximately 1.8 million workers aged 44 or older and living in Sweden in 2005 were followed up for 16 years, up to a maximum of 65 years of age. We linked mean values of job demands and job control, estimated in a job-exposure matrice (JEM) by gender, to individuals through their occupational titles in 2005. These values were categorized by rank order, and, for the construction of job-strain quadrants, we used a median cut-off. Associations with DP were estimated in Cox proportional-hazards models.

RESULTS

In models accounting for covariates including physical workload, low levels of job control were associated with higher risk of DP among both men and women. This association was most clear for DP with a psychiatric diagnosis, although a dose-response shape was found only among the men. High levels of job demands were associated with decreased risk of DP across diagnoses among men, but the same association varied from weak to non-existing among women. The high- and passive job-strain quadrants both showed increased risk of DP with a psychiatric diagnosis.

CONCLUSION

The results suggest that, at the occupational level, low job control, but not high job demands, contributes to an increased incidence of DP, particularly regarding DP with a psychiatric diagnosis.

Psychosocial Working Conditions and Subsequent Sickness Absence-Effects of Pain and Common Mental Disorders in a Population-Based Swedish Twin Sample

OBJECTIVE

To investigate pain and/or common mental disorders (CMDs) in the associations between psychosocial working conditions and sickness absence (SA) while controlling familial confounding.

METHODS

Prospective Prospective twin cohort study included survey data for pain and CMD, register data for SA and psychosocial working conditions. The follow-up from 2005 to 2016 of 28,916 twin individuals for first incident SA spell measured as the main International Classification of Diseases version 10 (ICD-10) diagnosis groups (F00-F99, I00-I99, and M00-M99), or the duration. We used regression models to obtain odds ratio (OR), incidence rate ratio (IRR), or relative risk ratio (RRR) with 95% confidence intervals (CI).

RESULTS

The covariate adjusted models of 9156 SA spells indicated almost no statistically significant associations between psychosocial working conditions and SA.

CONCLUSIONS

Psychosocial working conditions were not associated with SA while familial confounding could not be ruled out.

Effects of age on psychosocial working conditions and future labour market marginalisation: a cohort study of 56,867 Swedish twins

PURPOSE

Previous studies have reported an elevated risk of sickness absence (SA) and disability pension (DP) due to adverse psychosocial working conditions, yet the influence of age and familial factors on the associations have not been examined. We aimed to investigate associations between psychosocial working conditions and labour market marginalisation (LMM) in terms of unemployment, SA and DP adjusting for familial confounding and possible differences in these associations with different age groups and different unemployment and sick leave days.

METHODS

All twins living in Sweden in 2001, aged 16-64 years and not on old-age pension or DP were included (n = 56,867). The twins were followed from 2002 to 2016 regarding unemployment, SA and DP. Cox proportional hazards regression models were performed for the whole sample, and for discordant twin pairs, in five age groups.

RESULTS

Each one-unit increase in job demands and job control was associated with a lower risk of unemployment, SA and DP in all age groups. Moreover, each one-unit increase in social support was associated with an increased risk of 1-30 days unemployment in individuals older than 45 years and SA and DP. Social support decreased the risk of unemployment longer than 365 days in age groups 16-25 and 36-45 years. In the discordant twin pair analyses, the estimates attenuated towards statistical non-significance.

CONCLUSION

Even though familial factors seem to influence the associations between psychosocial working conditions and LMM, improving psychosocial working conditions by for example promoting high job control and social support at workplace may reduce the risk of future short- and long-term LMM in all age groups.

Disability pensions related to heavy physical workload: a cohort study of middle-aged and older workers in Sweden

OBJECTIVES

The aim of the study was to examine the associations between heavy physical workload among middle-aged and older workers and disability pension due to any diagnosis, as well as musculoskeletal, psychiatric, cardiovascular or respiratory diagnoses. The population-based design made it possible to examine dose-response and potential gender differences in the associations.

METHODS

About 1.8 million men and women aged 44-63 years and registered as living in Sweden in 2005 were followed regarding disability pension during 2006-2016, until ages 55-65 years. Mean values of physical workload and job control, estimated through gender-specific job-exposure matrices (JEMs), were assigned to individuals through their occupational titles in 2005. Exposure values were ranked separately for women and men and divided into quintiles. Associations were analyzed with Cox proportional-hazards regression.

RESULTS

The analyses showed robust, dose-response associations between physical workload and disability pension with a musculoskeletal diagnosis in both genders: the adjusted hazard ratio and 95% confidence interval for those with the heaviest exposure was 2.58 (2.37-2.81) in women and 3.34 (2.83-3.94) in men. Dose-response associations were also seen in relation to disability pension with a cardiovascular or a respiratory diagnosis, though the hazard ratios were smaller. Physical workload was not associated with disability pension with a psychiatric diagnosis after adjustment for job control.

CONCLUSION

This study of the entire Swedish population of middle-aged and older workers suggests that higher degrees of physical workload may increase the risk of disability pension overall, and specifically with musculoskeletal, cardiovascular or respiratory diagnosis, in both women and men.

Disability pension among persons with chronic disease: Differential impact of a Danish policy reform

BACKGROUND

In 2013, Denmark implemented a reform that tightened the criteria for disability pension, expanded a subsidized job scheme ('flexi-job') and introduced a new vocational rehabilitation scheme. The overall aim of the reform was to keep more persons attached to the labour market. This study investigates the impact of the reform among persons with chronic disease and whether this impact differed across groups defined by labour market affiliation and chronic disease type.

METHODS

The study was conducted as a register-based, nationwide cohort study. The study population included 480 809 persons between 40 and 64 years of age, who suffered from at least one of six chronic diseases. Hazard ratios (HR) and 95% confidence intervals (CI) of being awarded disability pension or flexi-job in the 5 years after vs. the 5 years prior to the reform were estimated.

RESULTS

Overall, the probability of being awarded disability pension was halved after the reform (HR = 0.49, CI: 0.47-0.50). The impact was largest for persons receiving sickness absence benefits (HR = 0.31, CI: 0.24-0.39) and for persons with functional disorders (HR = 0.38, CI: 0.32-0.44). Also, the impact was larger for persons working in manual jobs than for persons working in non-manual jobs. The probability of being awarded a flexi-job was decreased by one-fourth (HR = 0.76, CI: 0.74-0.79) with the largest impact for high-skilled persons working in non-manual jobs.

CONCLUSION

Access to disability pension and flexi-job decreased after the reform. This impact varied according to labour market affiliation and chronic disease type.

Cumulated and most recent job control and risk of disability pension in the Danish Work Life Course Cohort (DaWCo)

BACKGROUND

Previous studies have found low job control to be associated with a higher risk of disability pension (DP). Most studies have measured job control only at one time-point, and there is a lack of knowledge regarding the role of exposure duration. This study examines the prospective association between job control and DP measuring exposure both cumulated throughout work life and most recent.

METHODS

We included 712 519 individuals (about 4.5 million person-years) from The Danish Work Life Course Cohort which follows young employees in Denmark from their entry into the labour market. Job control was assessed with a job exposure matrix and DP with register data on public transfer payments. We adjusted for several potential life course confounders, including physical demands at work and parental socioeconomic position and psychiatric and somatic diagnoses.

RESULTS

Employees in occupations with low job control had a higher risk of DP. There were effects of both cumulated and most recent job control when mutually adjusted. Fully adjusted hazard ratios (HRs) were 1.14 [95% confidence intervals (CIs) 1.11-1.17] and 1.15 (95% CI 1.02-1.29) for cumulated and most recent job control, respectively. Without mutual adjustment, estimates were 1.15 (95% CI 1.13-1.18) and 1.55 (95% CI 1.39-1.72) for cumulated and most recent low job control, respectively.

CONCLUSIONS

Low job control predicts a higher risk of DP, even after adjustment for physical demands at work. The results indicate both gradual and short-term effects of low job control on DP risk.

Health behaviours and psychosocial working conditions as predictors of disability pension due to different diagnoses: a population-based study

BACKGROUND

To investigate whether the clustering of different health behaviours (i.e. physical activity, tobacco use and alcohol consumption) influences the associations between psychosocial working conditions and disability pension due to different diagnoses.

METHODS

A population-based sample of 24,987 Swedish twins born before 1958 were followed from national registers for disability pension until 2013. Baseline survey data in 1998-2003 were used to assess health behaviours and psychosocial Job Exposure Matrix for job control, job demands and social support. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

During follow-up, 1252 disability pensions due to musculoskeletal disorders (5%), 601 due to mental diagnoses (2%) and 1162 due to other diagnoses (5%) occurred. In the models controlling for covariates, each one-unit increase in job demands was associated with higher (HR 1.16, 95%CI 1.01-1.33) and in job control with lower (HR 0.87, 95%CI 0.80-0.94) risk of disability pension due to musculoskeletal disorders among those with unhealthy behaviours. Among those with healthy behaviours, one-unit increase of social support was associated with a higher risk of disability pension due to mental and due to other diagnoses (HRs 1.29-1.30, 95%CI 1.04-1.63).

CONCLUSIONS

Job control and job demands were associated with the risk of disability pension due to musculoskeletal disorders only among those with unhealthy behaviours. Social support was a risk factor for disability pension due to mental or other diagnoses among those with healthy behaviours. Workplaces and occupational health care should acknowledge these simultaneous circumstances in order to prevent disability pension.

Psychosocial working conditions, pain, mental disorders, and disability pension

We aimed to investigate associations between psychosocial working conditions and disability pension (DP), and the role of co-existing pain or common mental disorders (CMDs). Survey data collected 1998-2003 on 25,135 Swedish twins born 1935-1958 were linked with national DP register data until 2013. Psychosocial working conditions, pain and CMDs were analyzed by Cox proportional hazards regression models (hazard ratios with 95% confidence intervals). One unit increase in job demands or control was associated with a higher risk for DP due to musculoskeletal disorders. One unit decrease in job demands predicted lower risk of DP due to mental diagnoses. Co-existing pain or CMD played no role for associations of job demands with DP, but pain influenced the associations with DP due to mental diagnoses. To conclude, psychosocial working conditions play different roles for DP depending on the diagnoses.

Working conditions as risk factors for early exit from work-in a cohort of 2351 employees in Germany

Objectives

We would assess the possible impact of a range of physical and psychosocial working conditions on early exit from paid employment (i.e., before retirement age) in a representative employee population in Germany.

Methods

We analysed a cohort from the German Study on Mental Health at Work (S-MGA) with a baseline of 2351 employees in 2011/12, sampled randomly from the register of integrated employment biographies (IEB) at the Institute for Employment Research (IAB). Follow-up ended mid-2015. Early Exit comprised episodes of either pensioning, long-term sickness absence or unemployment ≥ 18 months. Total follow-up years were 8.422. Working conditions were partly assessed by the Copenhagen Psychosocial Questionnaire (COPSOQ). Through Cox regressions, associations of baseline working conditions with time to event of exit were estimated—adjusting for baseline age, gender, poverty, fixed-term contract and socioeconomic position.

Results

In multiple regressions, awkward body postures (HR = 1.24; 95% CI = 1.07–1.44), heavy lifting (1.17; 1.00–1.37) and high work pace (1.41; 1.16–1.72) were associated with exit. The estimated attributable fraction of exit for being exposed to less than optimal work environment was 25%. Regarding specific exit routes, repetitive movements (1.25; 1.03–1.53) increased the risk for the long-term sickness absence; work pace (1.86; 1.22–2.86) and role clarity (0.55; 0.31–1.00) were associated to unemployment; and control over working time (0.72; 0.56–0.95) decreased the risk of the early retirement.

Conclusions

Work environment seems to be important for subsequent early exit from work. Physical and psychosocial demands seem to be associated to exit to a stronger extent than resources at work.

Combinations of Job Demands and Job Control and Future Trajectories of Sickness Absence and Disability Pension An 11-year Follow-up of Two Million Employees in Sweden

OBJECTIVE

The aim of this study was to examine the association between combinations of job demands/control and future sickness absence (SA) and disability pension (DP) trajectories over 11 years.

METHODS

A population-based prospective cohort study of female (n = 1,079,631) and male (n = 1,107,999) employees in 2001. With group-based trajectory analysis, we modeled the trajectories of annual mean SA/DP days in 2002 to 2012. We predicted trajectory memberships for job demands/control using multinomial regression.

RESULTS

We found three SA/DP trajectories for women (low stable, medium stable, and high increasing) and two for men (low stable and high increasing). Low demands/low control in women [odds ratio (OR) 1.42; 95% confidence interval (95% CI) 1.38 to 1.45], and low demands and medium/high control in men (equal OR of 1.23; 95% CI 1.18 to 1.28) were strongly associated with high increasing trajectory.

CONCLUSION

The associations between job demands/control varied between SA/DP trajectories and between sexes.

Company-level determinants of disability retirement: a multilevel study of Finnish private sector workplaces

BACKGROUND

We examined whether the risk for disability retirement varies between companies over and above the individual-level characteristics of their employees and which company-level characteristics are associated with the risk for any, full or partial disability retirement.

METHODS

A 30% random sample of Finnish private sector companies with at least 10 employees was used (5567 companies and 301 313 employees). The risk for disability retirement over 6 years was analyzed using multilevel logistic regression. Company size and industry, as well as gender, age, education and social class measured both at the individual- and the company-level were used as explanatory variables.

RESULTS

3.8% of the variance in the risk for disability retirement was attributed to the company level after controlling for individual-level characteristics of the employees. Company-level variance was much larger in partial (11.7%) than in full (4.2%) disability retirement. After controlling for all individual- and company-level characteristics, those working in health and social work activities had increased risk for both full and partial disability retirement. The risk for full disability retirement increased by decreasing educational level of the company. The risk for partial disability retirement increased by increasing company size and was elevated in companies with the highest proportion of women.

CONCLUSIONS

After controlling for the individual-level characteristics, variation in the risk for disability retirement between companies was modest. The more substantial variation in partial disability pension suggests that companies have a marked role in advancing working with partial disabilities.

Job demands and control and sickness absence, disability pension and unemployment among 2,194,692 individuals in Sweden

Background: Knowledge is needed on associations between job demands and job control and long-term sickness absence (SA) and unemployment. We explored associations of job demands and job control with SA/disability pension (DP) and unemployment among women and men in paid work. Methods: We included all 2,194,694 individuals living in Sweden in 2001, aged 30–54 years, and in paid work. The Swedish Job Exposure Matrix (JEM) was used to ascertain levels of job demands and job control. Individuals were categorized into nine groups based on combinations of high, medium, or low values on both demands and control. Using multinomial logistic regression, we estimated odds ratios (OR) with 95% confidence intervals (CI) for the association of job demands and job control with risk of long-term SA/DP (>183 net days) and long-term unemployment (>183 days). Results: Regarding SA/DP, among women the risk was highest for those in occupations with low demands and low control (OR=1.32; 95% CI: 1.28–1.36), whereas among men the risk was highest among those in occupations with high demands and low control (OR=1.22; 1.11–1.34). Regarding unemployment, among women the risk was highest among those in occupations with low demands and medium control (OR=1.30; 1.24–1.37), whereas among men the risk was highest for those in occupations with low demands and high control (OR=1.54; 1.46–1.62). Conclusions: Using a JEM among all in a population rather than for specific occupations gives a more comprehensive view of the associations between job demands/job control and long-term SA/DP and unemployment, respectively.

The longitudinal integrated database for health insurance and labour market studies (LISA) and its use in medical research

Education, income, and occupation are factors known to affect health and disease. In this review we describe the Swedish Longitudinal Integrated Database for Health Insurance and Labour Market Studies (LISA, Longitudinell Integrationsdatabas för Sjukförsäkrings- och Arbetsmarknadsstudier). LISA covers the adult Swedish population aged ≥ 16 years registered on December 31 each year since 1990 (since 2010 individuals aged ≥ 15 years). The database was launched in response to rising levels of sick leave in the country. Participation in Swedish government-administered registers such as LISA is compulsory, and hence selection bias is minimized. The LISA database allows researchers to identify individuals who do not work because of injury, disease, or rehabilitation. It contains data on sick leave and disability pension based on calendar year. LISA also includes information on unemployment benefits, disposable income, social welfare payments, civil status, and migration. During 2000–2017, an average of 97,000 individuals immigrated to Sweden each year. This corresponds to about 1% of the Swedish population (10 million people in 2017). Data on occupation have a completeness of 95%. Income data consist primarily of income from employment, capital, and allowances, including parental allowance. In Sweden, work force participation is around 80% (2017: overall: 79.1%; men 80.3% and women 77.9%). Education data are available in > 98% of all individuals aged 25–64 years, with an estimated accuracy for highest attained level of education of 85%. Some information on civil status, income, education, and employment before 1990 can be obtained through the Population and Housing Census data (FoB, Folk- och bostadsräkningen).

Work-Related Biomechanical Exposure and Job Strain as Separate and Joint Predictors of Musculoskeletal Diseases: A 28-Year Prospective Follow-up Study

We investigated how work-related biomechanical exposure and job strain in midlife separately and jointly predicted back and degenerative musculoskeletal diseases (MSDs). A total of 6,257 employees participated in the Finnish Longitudinal Study on Aging Municipal Employees (FLAME) in 1981 and were followed up for 28 years. Risk ratios and the relative excessive risk due to interaction and 95% confidence intervals were modeled for separate and joint prediction estimates, respectively. After adjustment for confounders, job strain predicted degenerative MSDs among women after 4 and 11 years of follow-up. After 11 years, both exposures predicted both types of MSDs among men. Joint exposure predicted both types of MSDs after 4 years among women (for back MSDs, risk ratio (RR) = 1.58, 95% confidence interval (CI): 1.15, 2.18; for degenerative MSDs, RR = 1.59, 95% CI: 1.21, 2.07) and men (for back MSDs, RR = 1.50, 95% CI: 1.05, 2.15; for degenerative MSDs, RR = 1.61, 95% CI: 1.16, 2.22) and both types of MSDs after 11 years (for back MSDs, RR = 1.72, 95% CI: 1.21, 2.43; for degenerative MSDs, RR = 1.68, 95% CI: 1.25, 2.46) among men only, but the relative excessive risk due to interaction was not significant throughout. However, after 28 years, the separate and joint exposures did not predict MSDs. Workplace interventions should be focused on reducing job strain along with biomechanical exposure for possible prevention of MSDs in working life and around the time of retirement, but there may be other pathways of onset of MSDs in old age.

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.

The contribution from psychological, social, and organizational work factors to risk of disability retirement: a systematic review with meta-analyses

BACKGROUND

Previous studies indicate that psychological, social, and organizational factors at work contribute to health, motivation, absence from work, and functional ability. The objective of the study was to assess the current state of knowledge of the contribution of psychological, social, and organizational factors to disability retirement by a systematic review and meta-analyses.

METHODS

Data sources: A systematic literature search for studies of retirement due to disability in Medline, Embase, and PsychINFO was performed. Reference lists of relevant articles were hand-searched for additional studies.

DATA EXTRACTION

Internal validity was assessed independently by two referees with a detailed checklist for sources of bias. Conclusions were drawn based on studies with acceptable quality.

DATA SYNTHESIS

We calculated combined effect estimates by means of averaged associations (Risk ratios) across samples, weighting observed associations by the study's sample size. Thirty-nine studies of accepted quality were found, 37 of which from the Nordic countries.

RESULTS

There was moderate evidence for the role of low control (supported by weighted average RR = 1.40; 95% CI = 1.21-1.61) and moderate evidence for the combination of high demands and low control (although weighted average was RR = 1.45; 95% CI = 0.96-2.19) as predictors of disability retirement. There were no major systematic differences in findings between the highest rated and the lowest rated studies that passed the criterion for adequate quality. There was limited evidence for downsizing, organizational change, lack of employee development and supplementary training, repetitive work tasks, effort-reward imbalance to increase risk of disability pension. Very limited evidence was found for job demands, evening or night work, and low social support from ones superior.

CONCLUSIONS

Psychological and organizational factors at work contribute to disability retirement with the most robust evidence for the role of work control. We recommend the measurement of specific exposure factors in future studies.

Socioeconomic status and sick leave granted for mental and somatic disorders: a prospective study of young adult twins

Background

Low socioeconomic status (SES), indicated by low income and education, has consistently been found to be a strong predictor of sick leave. Several possible pathways from SES to sick leave have been described in previous literature, but there are also evidence indicating that the association can be confounded by common underlying factors. This study utilizes a population-based sample of employed young adult twins to estimate (i) the degree to which education and income are prospectively related to sick leave granted for mental, somatic, and any disorder, and (ii) whether these associations are confounded by familial factors.

Methods

Registry data on educational attainment and income at age 30 and subsequent sick leave were available for 6,103 employed young adult twins, among which there were 2,024 complete twin pairs. The average follow-up time was 6.57 years. Individual-level associations and fixed effects within twin pairs were estimated.

Results

Low education and income were associated with sick leave granted for both mental and somatic disorders, and with sick leave granted for any disorder. Associations were attenuated within dizygotic twin pairs and reduced to non-significance within monozygotic twin pairs, suggesting influence of familial factors on the associations between SES and sick leave.

Conclusions

Low SES is associated with a higher level of sick leave granted for both mental and somatic disorders among young adults, but these associations are confounded by factors that are common to co-twins. Education and income are therefore not likely to strongly affect sick leave in young adulthood.

Socioeconomic inequalities in cause-specific mortality after disability retirement due to different diseases

Aims: Socioeconomic inequalities in both disability retirement and mortality are large. The aim of this study was to examine socioeconomic differences in cause-specific mortality after disability retirement due to different diseases. Methods: We used administrative register data from various sources linked together by Statistics Finland and included an 11% sample of the Finnish population between the years 1987 and 2007. The data also include an 80% oversample of the deceased during the follow-up. The study included men and women aged 30-64 years at baseline and those who turned 30 during the follow-up. We used Cox regression analysis to examine socioeconomic differences in mortality after disability retirement. Results: Socioeconomic differences in mortality after disability retirement were smaller than in the population in general. However, manual workers had a higher risk of mortality than upper non-manual employees after disability retirement due to mental disorders and cardiovascular diseases, and among men also diseases of the nervous system. After all-cause disability retirement, manual workers ran a higher risk of cardiovascular and alcohol-related death. However, among men who retired due to mental disorders or cardiovascular diseases, differences in social class were found for all causes of death examined. For women, an opposite socioeconomic gradient in mortality after disability retirement from neoplasms was found. Conclusions: The disability retirement process leads to smaller socioeconomic differences in mortality compared with those generally found in the population. This suggests that the disability retirement system is likely to accurately identify chronic health problems with regard to socioeconomic status.

Upper body and lower limbs musculoskeletal symptoms and health inequalities in Europe: an analysis of cross-sectional data

BACKGROUND

Musculoskeletal disorders are the most frequent occupational diseases in Europe. However, their multifactorial aetiology poses several challenges concerning not only the estimation of relative prevalence rates across occupational groups but also how the co-occurrence of known risk factors might differ between disorders of the upper and lower limbs. Against this background, the following objectives are pursued: (1) to estimate the relative odds and prevalence rates of self-reported disorders of the upper limbs and/or shoulders and neck (upper body) and the lower limbs for major ISCO-88 occupational groups, (2) to evaluate to what extent the associations between known risk factors differ for musculoskeletal disorders of the upper body and the lower limbs.

METHODS

Statistical analysis of cross-sectional data from the European Working Conditions Survey 1995-2010. The probability of reporting upper body and lower limbs pain in the survey sample 2010 is estimated by mixed logistic regression models using the Markov chain Monte Carlo Sampler. Independent variables include some known physical and psychosocial risk factors.

RESULTS

Concerning the first objective, an excess risk of reporting musculoskeketal disorders of the upper body was observed among craft workers (ISCO 7), machine operators (ISCO 8) and workers in elementary occupations (ISCO 9). Concerning musculoskeletal disorders of the lower limbs, service and sales workers (ISCO 5) and workers in ISCO groups 7, 8 and 9 reported symptoms more frequently. Regarding the second objective, similar association patterns were observed for upper body and lower limbs symptoms. Major physical risk factors associated with both symptom types were very frequent exposure to tiring positions, carrying heavy loads and performing repetitive tasks. Standing appears to be an important risk factor for lower limbs symptoms only.

CONCLUSIONS

Results suggest that the unequal burden of exposure has not changed substantially across occupational groups since 1995, and that there is urgent need of delivering and evaluating the effects of specific interventions targeting workers at high risk of developing musculoskeletal disorders.