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OBJECTIVE: The Scandinavian Journal of Work, Environment & Health (SJWEH) was established half a century ago. This paper provides an overview of research on musculoskeletal disorders (MSD) published over these 50 years. Three themes are described: risk assessment, interventions to prevent work-related MSD, and interventions to support work participation. Finally, implications for future research are highlighted. METHODS: A systematic literature search was performed for all papers on MSD published in SJWEH. Each paper was coded on several criteria including research topic, type of MSD, risk factor(s), and number of citations. Findings were tabulated, and discussions within the author team defined the main results and future research directions. RESULTS: The search resulted in 1056 papers, of which 474 were included. The most reported-on MSD was low-back pain (LBP, 18%) and the most reported-on work-related risk factors were physically demanding work (14%) and psychosocial factors (12%). Research has contributed to improving case definitions, refining work-related exposure criteria, and recognizing the varying importance of physical and psychosocial factors across different MSD. Research on the association between work-related risk factors and LBP continues to emerge. Effective interventions for prevention of MSD are characterised by sufficient exposure reduction, while supporting work participation requires integrating health care, with multidisciplinary actions directed at factors involving the worker, employer, and workplace. CONCLUSION: Research has provided valuable insights into risk assessment, interventions for preventing work-related MSD, and supporting work participation. Intervention studies remain warranted and new areas include adopting whole-system approaches to prevent work-related MSD and promoting the concept of musculoskeletal health.

OBJECTIVES: The aim was to conduct a systematic review and meta-analysis investigating the association between occupational mechanical exposures and hip osteoarthritis. METHODS: The study was registered in PROSPERO. A systematic literature search was conducted in six databases to identify relevant articles. Two authors independently excluded articles, extracted data, assessed the risk of bias of each included article, and graded the level of evidence. We conducted a meta-analysis using random-effects model and performed a sensitivity analysis stratifying articles based on the risk of bias assessment, study design, and the outcome measurement. RESULTS: Twenty-four articles were eligible for inclusion. The highest pooled odds ratio (OR) was found for combined mechanical exposures [OR 1.7, 95% confidence interval (CI) 1.4–2.0], non-neutral postures (OR 1.7, 95% CI 1.4–2.1), lifting/carrying loads (OR 1.6, 95% CI 1.3–1.9), and climbing stairs (OR 1.6, 95% CI 1.1–2.2). The range of pooled OR for the remaining mechanical exposures (eg, standing, walking, kneeling, squatting, and sitting) was 0.6–1.6. Grading the quality of evidence, a moderate level of evidence was found for the combined mechanical exposures and for lifting/carrying loads. The remaining exposure categories were graded as having either low or very low levels of evidence. CONCLUSIONS: Considerable heterogeneity was observed across the included studies, and high-quality literature using objective exposure measurements is warranted. Despite various limitations affecting the comparability, occupational mechanical exposures seem to influence the likelihood of developing hip osteoarthritis.

OBJECTIVES: Limited knowledge exists about the association of lifting loads on a daily basis with physical and mental symptoms among warehouse workers. This study investigated associations between objectively measured lifting load and low-back pain (LBP), mental stress, and bodily fatigue after work and the following morning. METHODS: Warehouse workers (N=85) from the retail industry replied to daily questionnaires before and after work for 21 days about LBP intensity, mental stress, and bodily fatigue (outcome, all scales 0–10). We assessed lifting exposure using company records from the warehouse logistic systems on total lifting load (kg) per workday. Associations between variables were tested using linear mixed models with repeated measures controlling for relevant confounders. RESULTS: Mean daily lifting load was 1667.2 kg (range: 0–9998.4 kg). Compared to lifting 0–499 kg during a workday, lifting 500–1999 kg was associated with 0.59 points [95% confidence interval (CI) 0.10–1.08] elevated LBP intensity after work, while lifting ≥5000 showed a higher LBP intensity of 1.26 points (95% CI 0.48–2.03). LBP intensity remained elevated the following morning. Lifting ≥5000 kg was associated with higher mental stress after work of 0.74 points (95% CI 0.10–1.37), while no association was observed for bodily fatigue. CONCLUSIONS: Higher daily lifting loads were associated with higher LBP intensity after work and the following morning. These findings suggest that warehouses should consider the daily lifting loads when organizing warehouse work to prevent development of LBP, eg, using company records to provide a more equal distribution of daily lifting loads between workers.

OBJECTIVE: This study aimed to evaluate the effectiveness of motivational interviewing (MI) – a counselling approach offered by caseworkers at the Norwegian Labor and Welfare Administration (NAV) – on return to work (RTW) for individuals sick-listed for ≥8 weeks due to any diagnoses. MI was compared to usual case management and an active control during 12 months of follow-up. METHODS: In a randomized clinical trial with three parallel arms, participants were randomized to MI (N=257), usual case management (N=266), or an active control group (N=252). MI consisted of two MI sessions while the active control involved two sessions without MI, both were offered in addition to usual case management. The primary outcome was number of sickness absence days based on registry data. Secondary outcomes included time to sustainable RTW, defined as four consecutive weeks without medical benefits. RESULTS: The median number of sickness absence days for the MI group was 73 days [interquartile range (IQR) 31–147], 76 days (35–134) for usual care, and 75 days (34–155) for active control. In total 89%, 88% and 86% of the participants, respectively, achieved sustainable RTW. The adjusted hazard ratio (HR) for time to sustainable RTW was 1.12 (95% CI 0.90–1.40) for MI compared to usual case management and HR 1.16 (95% CI 0.93–1.44) compared to the active control. CONCLUSIONS: This study did not provide evidence that MI offered by NAV caseworkers to sick-listed individuals was more effective on RTW than usual case management or an active control. Providing MI in this context could be challenging as only half of the MI group received the intervention.

OBJECTIVE: This study aimed to examine duration of sickness absence due to knee osteoarthritis (OA) and sustained return to work (RTW) among municipal employees, who had at least one compensated sickness absence period due to knee OA. The contribution of sociodemographic characteristics, diabetes and previous sickness absence were assessed. We differentiated between participants with and without total knee arthroplasty (TKA). METHODS: Data from 123 506 employees in the Finnish Public Sector Study were linked with national health and mortality register information. There were 3 231 sickness absence periods (2372 participants) due to knee OA in 2005−2011. Kaplan-Meier curves for sustained RTW were obtained and median time with inter-quartile range (IQR) calculated for those with and without TKA. Cox regression analyses were carried out in multivariable analyses. RESULTS: The median time to RTW from the beginning of sickness absence was 21–28 days when TKA was not related to sickness absence and 92–145 days when it was. Among participants with no TKA, age 60−64, non-sedentary work, diabetes, and previous sickness absences predicted longer time to RTW, while pain medication predicted a shorter time. Among participants with TKA, non-sedentary work and previous sickness absences predicted a longer time to RTW. CONCLUSIONS: The clinical relevance of the difference in time to RTW between employees with or without TKA was substantial. Employees with knee OA working in physically demanding jobs need work modifications after TKA, and this calls for a dialog between occupational health care professionals and workplaces.

OBJECTIVE: This study aimed to estimate the proportion and number of incident upper-extremity musculoskeletal disorders (UEMSD) cases attributable to occupational risk factors in a working population. METHODS: Between 2002−2005, occupational physicians randomly selected 3710 workers, aged 20–59, from the Pays de la Loire (PdL) region. All participants underwent a standardized clinical examination. Between 2007−2010, 1611 workers were re-examined. This study included 1246 workers who were free of six main clinically diagnosed UEMSD at baseline but were diagnosed with at least one of these UEMSD at follow-up [59% of men, mean age: 38 (standard deviation 8.6) years]. Relative risks and population-attributable fractions (PAF) were calculated using Cox multivariable models with equal follow-up time and robust variance. The total number of incident UEMSD in the PdL region was estimated after adjustment of the sample weights using 2007 census data. The estimated number of potentially avoidable UEMSD was calculated by multiplying PAF by the total number of incident UEMSD in PdL. RESULTS: At follow-up, 139 new cases of UEMSD (11% of the study sample) were diagnosed. This represented an estimated 129 320 incident cases in the PdL in 2007. Following adjustment for personal factors, 26 381 (20.4% of all incident UEMSD) were attributable to high physical exertion, 16 682 (12.9%) to low social support, and 8535 (6.6%) to working with arms above shoulder level. CONCLUSIONS: A large number and important proportion of incident UEMSD may be preventable by reducing work exposures to physical exertion and working with arms above shoulder level as well as improving social support from co-workers/supervisors.

OBJECTIVE: Many employees have high physical exertion at work and suffer from musculoskeletal pain (MSP) leading to sickness absence with large costs. Participatory ergonomics is a potentially effective intervention for reducing physical exertion, MSP and sickness absence. The main aim of this study was to investigate the effectiveness of a 20-week workplace participatory ergonomic intervention among childcare workers on physical exertion and MSP. METHODS: In a two-arm cluster-randomized trial, 190 workers were recruited from 16 childcare institutions and randomly assigned to either a 20-week participatory ergonomics intervention consisting of three training workshops or a control group receiving usual care. Primary outcomes were physical exertion during work, maximal pain intensity, number of pain regions, and pain-related work interference. Secondary outcomes were MSP-related sickness absence, need for recovery (NFR), employee involvement, and self-efficacy. We followed the intention-to-treat principle and adhered to the registered study protocol (ISRCTN10928313). RESULTS: After 20 weeks, half the workers noticed some positive changes in their work. However, there were no statistically discernible effects in physical exertion, maximum pain intensity, pain-related work interference, or number of pain regions. We found a significant reduction of MSP-related sickness absence in the intervention compared to the control group [-0.48 days per month (95% confidence interval (CI), -0.8– -0.1]. We found no significant effects in NRF or involvement of employees, but self-efficacy was reduced in the intervention compared to the control group [-0.2 (95% CI, -0.3– -0.0)]. CONCLUSION: This 20-week training for a participatory ergonomic intervention in childcare workers did not show effects on physical exertion and MSP, but was both feasible and effective in reducing MSP-related sickness absence.

OBJECTIVES: This study aimed to investigate whether inpatient multimodal occupational rehabilitation (I-MORE) reduces sickness absence (SA) more than outpatient acceptance and commitment therapy (O-ACT) among individuals with musculoskeletal and mental health disorders. METHODS: Individuals on sick leave (2-12 months) due to musculoskeletal or common mental health disorders were randomized to I-MORE (N=86) or O-ACT (N=80). I-MORE lasted 3.5 weeks in which participants stayed at the rehabilitation center. I-MORE included ACT, physical exercise, work-related problem solving and creating a return to work plan. O-ACT consisted mainly of 6 weekly 2.5 hour group-ACT sessions. We assessed the primary outcome cumulative SA within 6 and 12 months with national registry-data. Secondary outcomes were time to sustainable return to work and self-reported health outcomes assessed by questionnaires. RESULTS: SA did not differ between the interventions at 6 months, but after one year individuals in I-MORE had 32 fewer SA days compared to O-ACT (median 85 [interquartile range 33–149] versus 117 [interquartile range 59–189)], P=0.034). The hazard ratio for sustainable return to work was 1.9 (95% confidence interval 1.2–3.0) in favor of I-MORE. There were no clinically meaningful between-group differences in self-reported health outcomes. CONCLUSIONS: Among individuals on long-term SA due to musculoskeletal and common mental health disorders, a 3.5-week I-MORE program reduced SA compared with 6 weekly sessions of O-ACT in the year after inclusion. Studies with longer follow-up and economic evaluations should be performed.

OBJECTIVE: Research on the effectiveness of vocational rehabilitation has focused on small and selected groups, lacked proper controls, or not captured dynamic changes in work participation. Using rich nationwide data on vocational rehabilitees and matched controls, long-term changes in work participation before and after vocational rehabilitation were examined to assess its effectiveness. METHODS: Representative Finnish register data were used to examine 3199 recently employed individuals aged 30–55 years with histories of musculoskeletal- and mental-related work disability starting vocational rehabilitation in 2008–2010 (intervention group), and 3199 propensity score matched non-rehabilitees (control group). Sociodemographic and work-related factors and detailed 3-year work disability and other labor market history were used for matching. Generalized estimation equations were used to examine differences in the proportion of time spent at work between periods before and after rehabilitation among the intervention and control group and the difference in these differences (DID). RESULTS: Vocational rehabilitation resulted in gains in work participation, the total 1-, 2-, and 3-year DID being 11.8 [95% confidence interval (CI) 10.0–13.7], 8.9 (95% CI 7.6–10.2), and 7.2 (95% CI 6.1–8.3) percentage points, respectively. Contrary to this overall pattern, larger DID was observed over the long term for those whose rehabilitation lasted >10 months. The DID was lowest among women with musculoskeletal diseases. CONCLUSIONS: Vocational rehabilitation after musculoskeletal- or mental-related work disability showed modest effectiveness on work participation. To promote sustained work participation after shorter rehabilitation (likely comprising workplace interventions) and faster work resumption after longer rehabilitation (likely comprising training), enhanced and complementary interventions should be considered.

OBJECTIVES: We analyzed social security costs based on an earlier quasi-experiment that compared work participation between partial sickness beneficiaries and a matched group of full sickness beneficiaries. METHODS: Utilizing a population-based 70% representative sample, 1878 persons with part-time sick leave (intervention group) due to musculoskeletal diseases or mental disorders at an early stage of work disability and their propensity-score-matched controls with full-time sick leave were followed for two years. The outcome was the difference (absolute and relative) in social security costs between the intervention and control groups during follow-up. Costs of sickness absence, vocational rehabilitation, unemployment, and retirement days were calculated from national administrative registers. RESULTS: A cost reduction of €2395 per person per year [95% confidence interval (CI) -2890– -1899) was observed in the intervention compared with the control group. The cost ratio was 0.512 (95% CI 0.511–0.513). The largest savings were attributable to differences in the costs of retirement and vocational rehabilitation. The savings were higher for the second compared with the first follow-up year. Costs were saved across both genders and diagnostic groups, however, savings for women with musculoskeletal diseases were lowest. CONCLUSIONS: Part-time instead of full-time sick leave, at the early stage of work disability due to musculoskeletal diseases or mental disorders, leads to considerable social security cost savings during two years, in correspondence with increased work participation and in addition to earlier reported health benefits. Part-time sick leave can be recommended from an economic perspective; however more consideration should be given to women with musculoskeletal diseases.

OBJECTIVES: Using an employer’s perspective, this study aimed to compare the immediate and longer-term impact of workplace ergonomics and neck-specific exercise versus ergonomics and health promotion information on health-related productivity among a general population of office workers and those with neck pain. METHODS: A prospective one-year cluster randomized trial was conducted. Participants received an individualized workstation ergonomics intervention, combined with 12 weeks of either workplace neck-specific exercises or health promotion information. Health-related productivity at baseline, post-intervention and 12-months was measured with the Health and Work Performance Questionnaire. Intention-to-treat analysis was performed using multilevel mixed models. RESULTS: We recruited 763 office workers from 14 organizations and allocated them to 100 clusters. For the general population of office workers, monetized productivity loss at 12 months [AU$1464 (standard deviation [SD] 1318) versus AU$1563 (SD=1039); P=0.023]; and presenteeism at 12 months [2.0 (SD 1.2) versus 2.4 (SD 1.4); P=0.007] was lower in the exercise group compared to those in the health promotion information group. For office workers with neck pain, exercise participants had lower sickness absenteeism at 12 months compared to health promotion information participants [0.7 days (SD 1.0) versus 1.4 days (SD 3.1); P-=0.012], despite a short-term increase in sickness absenteeism post-intervention compared to baseline for the exercise group [1.2 days (SD 2.2) versus 0.6 days (SD 0.9); P

OBJECTIVES: We sought to determine whether interventions that target work organization or the psychosocial work environment are effective in preventing or reducing work-related musculoskeletal disorders (WMSD) compared to usual work. METHODS: We systematically reviewed the 2000–2015 English- and French-language scientific literature, including studies evaluating the effectiveness of an organizational or psychosocial work intervention on incidence, prevalence or intensity of work-related musculoskeletal pain or disorders in the neck, shoulders, upper limbs and/or back or of work absence due to such problems, among non-sick-listed workers. We excluded rehabilitation and individual-level behavioral interventions and studies with >50% attrition. We analyzed medium- and high-quality studies and synthesized the evidence using the Grading of Recommendations Assessment, Development & Evaluation (GRADE) approach. An analysis of key workplace intervention elements supplemented the interpretation of results. RESULTS: We identified 884 articles; 28 met selection criteria, yielding 2 high-quality, 10 medium-quality and 16 low-quality studies. There was moderate evidence that supplementary breaks, compared to conventional break schedules, are effective in reducing symptom intensity in various body regions. Evidence was low-to-very-low quality for other interventions, primarily due to risk of bias related to study design, high attrition rates, co-interventions, and insensitive indicators. Most interventions lacked key intervention elements, such as work activity analysis and ergonomist guidance during implementation, but the relation of these elements to intervention effectiveness or ineffectiveness remains to be demonstrated. CONCLUSIONS: Targeting work–rest cycles may reduce WMSD. Better quality studies are needed to allow definitive conclusions to be drawn on the effectiveness of other work organizational or psychosocial interventions to prevent or reduce WMSD.

OBJECTIVE: The aim of this study was to develop a prediction model based on variables measured in occupational health checks to identify non-sick listed workers at risk of sick leave due to non-specific low-back pain (LBP). METHODS: This cohort study comprised manual (N=22 648) and non-manual (N=9735) construction workers who participated in occupational health checks between 2010 and 2013. Occupational health check variables were used as potential predictors and LBP sick leave was recorded during 1-year follow-up. The prediction model was developed with logistic regression analysis among the manual construction workers and validated in non-manual construction workers. The performance of the prediction model was evaluated with explained variances (Nagelkerke’s R-square), calibration (Hosmer-Lemeshow test), and discrimination (area under the receiver operating curve, AUC) measures. RESULTS: During follow-up, 178 (0.79%) manual and 17 (0.17%) non-manual construction workers reported LBP sick leave. Backward selection resulted in a model with pain/stiffness in the back, physician-diagnosed musculoskeletal disorders/injuries, postural physical demands, feeling healthy, vitality, and organization of work as predictor variables. The Nagelkerke’s R-square was 3.6%; calibration was adequate, but discrimination was poor (AUC=0.692; 95% CI 0.568–0.815). CONCLUSIONS: A prediction model based on occupational health check variables does not identify non-sick listed workers at increased risk of LBP sick leave correctly. The model could be used to exclude the workers at the lowest risk on LBP sick leave from costly preventive interventions.

OBJECTIVES: This study aimed to identify return-to-work (RTW) trajectories among workers with work-related musculoskeletal disorders (MSD) and examine the associations between different MSD and these RTW trajectories. METHODS: We used administrative workers’ compensation data to identify accepted MSD lost-time claims with an injury date between 2010–2012 in British Columbia, Canada. Cox regression analyses were used to investigate differences in time to RTW between MSD. Validated day-to-day calendar measures of four RTW states (sickness absence, modified RTW, RTW, and non-RTW) were grouped into RTW trajectories spanning a one-year period using sequence analysis. RTW trajectories were clustered using decision rules that identified a shared trajectory structure. Poisson regression with robust standard errors was used to estimate relative risk ratios (RR) with 95% confidence intervals (CI) between MSD and RTW trajectory clusters. RESULTS: In a cohort of 81 062 claims, 2132 unique RTW trajectories were identified and clustered into nine RTW trajectory clusters. Half of the workers sustainably returned to work within one month. Workers with back strains were most likely to have trajectories characterized by early sustained RTW, while workers with fractures or dislocations were more likely to have prolonged sickness absence trajectories (RR 4.9–9.9) or non-RTW trajectories (RR 1.4–7.6). CONCLUSION: This is the first study that has characterized different types of RTW trajectories of workers with MSD using sequence analysis. The application of sequence analysis and the identification of RTW trajectories yielded a number of key insights not found using conventional cox regression analysis.

OBJECTIVES: This study evaluates the Danish national Job & Body campaign on beliefs about musculoskeletal pain and work. METHODS: Initiated in 2011, a national campaign in Denmark targeted public sector employees with a mixture of networking activities, workplace visits, and a mass media outreach with topics related to job and body (eg, musculoskeletal pain, movement and work) and creating balance between demands at work and physical capacity. At baseline (2011) and at four time points until the end of 2014, random cross-sectional samples of ≥≥1000 representative public sector employees (total N=5012) replied to eight questions concerning beliefs about musculoskeletal pain and work. Changes over time were modelled using general linear models (averaged for all questions, 0–100 points, where 0 is completely negative and 100 completely positive) and logistic regression analyses (for the single questions) controlling for age, gender and a number of work-related factors. RESULTS: At the last follow-up in 2014, 17.3% of public sector employees were familiar with the campaign. Beliefs about musculoskeletal pain and work were 3.4 points (95% CI 2.4–4.3) higher than at baseline. For the single questions, 4 out of 8 showed improved odds for more positive beliefs [odds ratios (OR) of 1.28–1.89]. CONCLUSION: During follow-up of the national campaign, beliefs about musculoskeletal pain and work were more positive among public sector employees in Denmark. Due to the time-wise mixture of several campaign activities, the isolated effect of each component could not be disentangled. Whether changes in health occurred remain unknown.

OBJECTIVE: This study aimed to develop and validate a risk screening tool using a points system to assess the risk of future disability retirement due to musculoskeletal disorders (MSD). METHODS: The development population, the Health 2000 Survey, consisted of a nationally representative sample of Finnish employees aged 30–60 years (N=3676) and the validation population, the Helsinki Health Study, consisted of employees of the City of Helsinki aged 40–60 years (N=6391). Both surveys were linked to data on disability retirement awards due to MSD from national register for an 11-year follow-up. RESULTS: The discriminative ability of the model with seven predictors was good (Gönen and Heller’s K concordance statistic=0.821). We gave points to seven predictors: sex-dependent age, level of education, pain limiting daily activities, multisite musculoskeletal pain, history of arthritis, and surgery for a spinal disorder or carpal tunnel syndrome. A score of 3 or higher out of 7 (top 30% of the index) had good sensitivity (83%) and specificity (70%). Individuals at the top 30% of the risk index were at 29 [95% confidence interval (CI) 15–55) times higher risk of disability retirement due to MSD than those at the bottom 40%. CONCLUSION: This easy-to-use screening tool based on self-reported risk factor profiles can help identify individuals at high risk for disability retirement due to MSD.

OBJECTIVES: Low-back pain (LBP) is a substantial health challenge due to the risk for long-term sickness absence and early retirement. Several biomechanical exposures at work, including sitting, have been suggested to increase the risk for LBP. The objectives of this study were to determine (i) the extent to which temporal patterns and total amount of objectively measured sitting is associated with LBP intensity and (ii) whether selected modifiers influence these associations. METHODS: This cross sectional study uses baseline data from the Danish PHysical ACTivity cohort with Objective measurements (DPhacto) of physical activities in the cleaning, transport and manufacturing sectors. Peak intensity of LBP was collected by questionnaire on a 0–10 scale and sitting was expressed in terms of total duration and temporal pattern, ie, time spent in brief bursts (≤5 minutes), moderate periods (>5–≤20 minutes), and prolonged periods of sitting (>20 minutes); both during work and whole day (waking hours only). Associations were determined using linear regression in models accounting for moderation and confounding. Factors evaluated as moderators or confounders were assessed by questionnaire. RESULTS: The population consisted of 704 participants. No significant associations were found between total duration or temporal patterns of sitting and LBP intensity, neither during work nor for the whole day. Body mass index (BMI) significantly moderated the association between sitting and LBP; participants with a high and low BMI showing a negative and positive association, respectively. CONCLUSION: Sitting was not independently associated with peak LBP intensity, suggesting other exposures are more powerful risk factors for LBP.

OBJECTIVES: Work-related musculoskeletal disorders (MSD) are highly prevalent and put a large burden on (working) society. Primary prevention of work-related MSD focuses often on physical risk factors (such as manual lifting and awkward postures) but has not been too successful in reducing the MSD burden. This may partly be caused by insufficient knowledge of etiological mechanisms and/or a lack of adequately feasible interventions (theory failure and program failure, respectively), possibly due to limited integration of research disciplines. A research framework could link research disciplines thereby strengthening the development and implementation of preventive interventions. Our objective was to define and describe such a framework for multi-disciplinary research on work-related MSD prevention. METHODS: We described a framework for MSD prevention research, partly based on frameworks from other research fields (ie, sports injury prevention and public health). RESULTS: The framework is composed of a repeated sequence of six steps comprising the assessment of (i) incidence and severity of MSD, (ii) risk factors for MSD, and (iii) underlying mechanisms; and the (iv) development, (v) evaluation, and (vi) implementation of preventive intervention(s). CONCLUSIONS: In the present framework for optimal work-related MSD prevention, research disciplines are linked. This framework can thereby help to improve theories and strengthen the development and implementation of prevention strategies for work-related MSD.

OBJECTIVES: The aim of this study was to investigate the association between the length of sickness absence and sustained return to work (SRTW) and the predictors of SRTW in depression, anxiety disorders, intervertebral disc disorders, and back pain in a population-based cohort of employees in the Finnish public sector. METHODS: We linked data from employers’ registers and four national population registers. Cox proportional hazards regression analysis with a cluster option was applied. SRTW was defined as the end of the sickness benefit period not followed by a recurrent sickness benefit period in 30 days. RESULTS: For depression, the median time to SRTW was 46 and 38 days among men and women, respectively. For anxiety disorders, the figures were 24 and 22 days, for intervertebral disc disorders, 42 and 41 days, and, for back pain, 21 and 22 days among men and women respectively. Higher age and the persistence of the health problem predicted longer time to SRTW throughout the diagnostic categories. Comorbid conditions predicted longer time to SRTW in depression and back pain among women. CONCLUSIONS: This large cohort study adds scientific evidence on the length of sickness absence and SRTW in four important diagnostic categories among public sector employees in Finland. Further research taking into account, eg, features of the work environment is suggested. Recommendations on the length of sickness absence at this point should be based on expert opinion and supplemented with research findings.

OBJECTIVES: Work-related stress has been linked to increased risk of disability pensioning, but the association between perceived justice of managerial behavior and decision-making processes at the workplace (ie, organizational justice) and risk of disability pensioning remains unknown. We examined the associations of organizational justice and its relational and procedural components with all-cause and diagnosis-specific disability pensions with repeated measures of justice. METHODS: Data from 24 895 employees responding to repeated surveys on organizational justice in 2000–2002 and 2004 were linked to the records of a national register for disability pensions from 2005–2011. Associations of long-term organizational justice (average score from two surveys) with disability pensions were studied with Cox proportional hazard regression adjusted for demographics, socioeconomic status, baseline health and health risk behavior, stratified by sex. RESULTS: During a mean follow-up of 6.4 years, 1658 (7%) employees were granted disability pension (282 due to depression; 816 due to musculoskeletal diseases). Higher organizational justice was associated with a lower risk of disability pensioning [hazard ratio (HR) per one-unit increase in 5-point justice scale 0.87 (95% CI 0.81–0.94)]. For disability pension due to depression and musculoskeletal diseases, the corresponding HR were 0.77 (95% CI 0.65–0.91) and 0.87 (95% CI 0.79–0.97), respectively. Adjustment for job strain and effort–reward imbalance attenuated the HR by 20–80%. CONCLUSIONS: Supervisors` fair treatment of employees and fair decision-making in the organizations are associated with a decreased risk of disability pensioning from all-causes, depression and musculoskeletal diseases. These associations may be attributable to a wider range of favorable work characteristics.

OBJECTIVES: The aim of this study was twofold: to investigate socioeconomic differences in disability retirement (DR) due to major diseases and find out which diseases contribute most to the overall socioeconomic differences in DR. METHODS: The data were longitudinal register-based (10% sample of Finns) from Statistics Finland. These data included 258 428 participants aged 35–64 years during the follow-up. The participants were employed or unemployed before the follow-up period 1997–2010. Of all participants, 14 303 men and 13 188 women ended up in DR during the follow-up. Socioeconomic status was categorized into upper- and lower-class non-manual employees, manual workers, and self-employed persons. Cox models were used to estimate hazard ratios for DR due to different diseases. RESULTS: Compared to upper-class non-manual employees, DR was especially high for manual workers whose retirement diagnoses included psychoactive substance use, musculoskeletal diseases (MSD), or cardiovascular diseases. Socioeconomic differences in DR were stronger for younger age groups and men versus women. For females and males, the largest part of the excess DR among manual workers compared to upper-class non-manual employees was due to MSD. In the age group 54–64 years, the contribution of MSD to the total excess was >50% among male manual workers and 75% among female manual workers. Excess DR due to mental disorders concerned only 35–54-year-old manual workers (among 23% men and 26% women). CONCLUSION: The contribution of MSD to the total excess DR among lower socioeconomic groups was large. Prevention of MSD among manual workers would likely reduce socioeconomic differences in DR.

OBJECTIVES: Job strain has previously been shown to predict disability pension, but it is unknown whether effort-reward imbalance (ERI), another major stress model, is also associated with disability pension. METHODS: We examined ERI as a risk factor for diagnosis-specific disability pension in a cohort of 51 874 public-sector employees in Finland. To control for reporting bias, work unit-level scores of ERI (based on the survey responses of 35 260 employees in 2000–2002) were constructed and linked to all eligible employees. A sub-cohort of the respondents was analyzed also with individual-level ERI. Disability pension data were derived from national pension registers with no loss to follow-up. The outcomes were all-cause disability pension and disability pension due to depression, musculoskeletal diseases, and ischemic heart diseases (IHD). Multivariate Cox proportional hazard models (adjusted for sociodemographic factors, baseline health, and work-related characteristics) were used for analyses. RESULTS: During a mean 8.9 years of follow-up, 4542 participants were granted disability pension. An increased risk for disability pension due to depression was detected for both high work unit- and individual-level ERI [hazard ratio (HR) 1.63, 95% confidence interval (95% CI) 1.31–2.04 and HR 1.90, 95% CI 1.51–2.40, respectively]. High individual-level ERI increased the risk of disability pension due to musculoskeletal diseases (HR 1.32, 95% CI 1.13–1.53), but no association was observed for work unit-level ERI (HR 1.02, 95% CI 0.88–1.19). ERI was not associated with disability pension due to IHD. CONCLUSION: The present study showed a consistent association between high ERI and an increased risk of disability pension due to depression.

OBJECTIVE: We studied predictors of sickness absences (SA) due to musculoskeletal pain over two years among 386 municipal female kitchen workers. METHODS: Pain and SA periods (no/yes) due to pain in seven sites during the past three months were assessed at 3-month intervals over two years by questionnaire. Age, musculoskeletal pain, multisite pain (pain in ≥3 sites), musculoskeletal and other somatic diseases, depressive symptoms, physical and psychosocial workload, body mass index, smoking, and leisure-time physical activity (LTPA) at baseline were considered as predictors. Trajectory analysis and multinomial logistic regression were used. RESULTS: Three trajectories of SA emerged, labelled as “none” (41% of the subjects), “intermediate” (48%), and “high” (11%). With the “none” trajectory (no SA) as reference, pain in all musculoskeletal sites excepting the low back predicted belonging to the “intermediate” [odds ratio (OR) 1.82–2.48] or “high” (OR 2.56–3.74) trajectory adjusted for age; multisite pain predicted membership of the “intermediate” [OR 2.15, 95% confidence interval (95% CI) 1.38–3.34] or “high” (OR 4.66, 95% CI 2.10–10.3) trajectories. In a mutually adjusted final model, smoking (OR 2.12, 95% CI 1.22–3.69), multisite pain (OR 1.87, 95% CI 1.15–3.02), and overweight/obesity (OR 1.71, 95% CI 1.08–2.72) predicted belonging to the “intermediate” trajectory, while depressive symptoms (OR 3.57, 95% CI 1.57–8.10), musculoskeletal diseases (OR 3.18, 95% CI 1.37–7.37), and multisite pain (OR 2.72, 95% CI 1.15–6.40) were associated with the “high” trajectory. CONCLUSION: Along with the number of pain sites and musculoskeletal diseases, attention to depressive symptoms, smoking, and overweight/obesity is needed to tackle SA related to musculoskeletal pain.

OBJECTIVES: The aim of this review was to assess what types of socioeconomic positions (SEP) are being considered in randomized controlled intervention studies and estimate the moderation of SEP in workplace intervention effects on body mass index (BMI), fruit and vegetable consumption, musculoskeletal symptoms, and job stress. METHODS: A meta-analysis of randomized controlled workplace interventions was undertaken. Studies were classified by participants’ SEP. The overall standardized mean difference (SMD) for each outcome was estimated with random-effects models. Additionally, a random-effects model with SEP as moderating variable was calculated in order to assess intervention effect modification (EM). RESULTS: This review covers 36 studies. Altogether 40 reports of intervention effects were considered. The overall mean differences in the models, without SEP as moderating variable, were significant for all outcomes. BMI, self-reported musculoskeletal symptoms, and self-reported job stress decreased [SMD -0.16, 95% confidence interval (95% CI) -0.29– -0.02, SMD -0.32, 95% CI -0.51– -0.14, and SMD -0.37, 95% CI -0.71– -0.04, respectively], whereas daily consumption of fruit and vegetables increased (SMD 0.12, 95% CI 0.01–0.22). There were no statistically significant differences between occupational classes for the health outcomes considered (SMD -0.102, 95% CI -0.264–0.060, EM -0.141, 95% CI -0.406–0.125; SMD 0.117, 95% CI -0.049–0.282, EM 0.000, 95% CI -0.230–0.231; SMD -0.301, 95% CI -0.494– -0.107, EM -0.369, 95% CI -1.169–0.430; and SMD -0.200, 95% CI -0.524–0.124, EM -0.598, 95% CI -1.208–0.012, respectively). CONCLUSIONS: Workplace interventions can achieve small positive effects on major health outcomes. We could not confirm whether these effects are moderated by occupational class.

OBJECTIVES: This study aims to examine the extent to which a greater prevalence of pre-existing chronic conditions among older workers explains why older age is associated with longer duration of sickness absence (SA) following a musculoskeletal work-related injury in British Columbia. METHODS: A secondary analysis of workers’ compensation claims in British Columbia over three time periods (1997–1998; 2001–2002, and 2005–2006), the study comprised 102 997 and 53 882 claims among men and women, respectively. Path models examined the relationships between age and days of absence and the relative contribution of eight different pre-existing chronic conditions (osteoarthritis, rheumatoid arthritis, hypertension, coronary heart disease, diabetes, thyroid conditions, hearing problems, and depression) to this relationship. Models were adjusted for individual, injury, occupational, and industrial covariates. RESULTS: The relationship between age and length of SA was stronger for men than women. A statistically significant indirect effect was present between older age, diabetes, and longer days of SA among both men and women. Indirect effects between age and days of SA were also present through osteoarthritis, among men but not women, and coronary heart disease, among women but not men. Depression was associated with longer duration of SA but was most prevalent among middle-aged claimants. Approximately 70–78% of the effect of age on days of SA remained unexplained after accounting for pre-existing conditions. CONCLUSIONS: Pre-existing chronic conditions, specifically diabetes, osteoarthritis and coronary heart disease, represent important factors that explain why older age is associated with more days of SA following a musculoskeletal injury. Given the increasing prevalence of chronic conditions among labor market participants (and subsequently injured workers) moderate reductions in age differences in SA could be gained by better understanding the mechanisms linking these conditions to longer durations of SA.

OBJECTIVES: This study aimed to examine the effect of an ergonomic hazard control (HC) initiative, undertaken as part of a company ergonomics standard, on worker injury risk. METHODS: Using the company’s ergonomic hazards database to identify jobs with and without ergonomic HC implementation and linking to individual job and injury histories, injury risk among person-jobs with HC implementation (the HC group) was compared to those without HC (NoHC group) using random coefficient models. Further analysis of the HC group was conducted to determine the effect of additional ergonomic hazards controlled on injury risk. RESULTS: Among 123 jobs at 17 plant locations, 347 ergonomic hazards were quantitatively identified during the study period. HC were implemented for 204 quantified ergonomic hazards in 84 jobs, impacting 10 385 persons (12 967 person-jobs). No HC were implemented for quantified ergonomic hazards in the remaining 39 jobs affecting 4155 persons (5046 person-jobs). Adjusting for age, sex, plant origin, and year to control for any temporal trend in injury risk, the relative risk (RR) for musculoskeletal disorder (MSD) was 0.85 and the RR for any injury or MSD was 0.92 in the HC compared to NoHC group. Among the HC group, each ergonomic hazard controlled was associated with risk reduction for MSD and acute injury outcomes (RR 0.93). CONCLUSION: Systematic ergonomic HC through participatory ergonomics, as part of a mandatory company ergonomics standard, is associated with MSD and injury risk reduction among workers in jobs with HC implemented.

OBJECTIVES: The prevalence of musculoskeletal pain in European countries varies considerably. We analyzed data from the fifth European Working Conditions Survey (EWCS) to explore the role of personal, occupational, and social risk factors in determining the national prevalence of musculoskeletal pain. METHODS: Over the course of 2010, 43 816 subjects from 34 countries were interviewed. We analyzed the one-year prevalence of back and neck/upper-limb pain. Individual-level risk factors studied included: sex; age; educational level; socioeconomic status; housework or cooking; gardening and repairs; somatizing tendency; job demand–control; six physical occupational exposures; and occupational group. Data on national socioeconomic variables were obtained from Eurostat and were available for 28 countries. We fitted Poisson regression models with random intercept by country. RESULTS: The main analysis comprised 35 550 workers. Among individual-level risk factors, somatizing tendency was the strongest predictor of the symptoms. Major differences were observed by country with back pain more than twice as common in Portugal (63.8%) than Ireland (25.7%), and prevalence rates of neck/upper-limb pain ranging from 26.6% in Ireland to 67.7% in Finland. Adjustment for individual-level risk factors slightly reduced the large variation in prevalence between countries. For back pain, the rates were more homogenous after adjustment for national socioeconomic variables. CONCLUSIONS: Our analysis indicates substantial variation between European countries in the prevalence of back and neck/upper-limb pain. This variation is unexplained by established individual risk factors. It may be attributable in part to socioeconomic differences between countries, with higher prevalence where there is less risk of poverty or social exclusion.

OBJECTIVES: This study aimed to examine between-county differences in disability retirement due to main diagnosis groups and explain these differences by individual-level demographic and work-related factors and municipality-level characteristics. METHODS: A 20% random sample of the Finnish social insured population aged 25-62 years at the end of 2006 was followed for disability retirement until the end of 2011. Individual-level demographic and work-related covariates were derived from the registers of the Finnish Centre for Pensions and complemented by municipality-level covariates from the national SotkaNet databank. Standardized disability retirement rates were calculated and logistic regression analysis was used to examine between-county differences during the 5-year follow-up. RESULTS: In the county with the highest incidence, disability retirement was nearly twice as common as in the county with the lowest incidence. The between-county differences were larger in disability retirement due to cardiovascular and musculoskeletal diseases than other causes. Adjusting for demographic and work-related characteristics explained a third of the differences. Further adjustment for municipal characteristics explained up to 60% of the differences. However, in regions of Northern and Eastern Finland with the highest incidence of disability retirement, 20–30% excess incidence remained even after all adjustments. CONCLUSIONS: Large differences exist in disability retirement between Finnish counties. Disability retirement due to musculoskeletal diseases has the highest impact on the overall differences. Demographic structure and work-related characteristics but also municipality-level characteristics contribute to these differences.

OBJECTIVE: Research and interventions targeting the relationship between work, its attendant occupational hazards, and obesity are evolving but merit further consideration in the public health arena. In this discussion paper, conceptual heuristic models are described examining the role of obesity as both a risk factor and health outcome in the occupational setting. METHODS: PubMed was searched using specific criteria from 2000 and onwards for evidence to support conceptual models in which obesity serves as a risk factor for occupational disease or an outcome of occupational exposures. Nine models are presented: four where obesity is a risk factor and five where it is an adverse effect. RESULTS: A broad range of work-related health effects are associated with obesity including musculoskeletal disorders, asthma, liver disease, and cardiovascular disease, among others. Obesity can be associated with occupational hazards such as shift work, sedentary work, job stress, and exposure to some chemicals. CONCLUSION: Identification of combinations of risk factors pertinent to obesity in the occupational environment will provide important guidance for research and prevention.

OBJECTIVE: The aim of this study was to examine the joint association of sleep duration and insomnia symptoms with subsequent disability retirement. METHODS: Baseline survey data were collected in 2000–2002 from 40–60-year-old employees of the City of Helsinki, all working at baseline. Baseline data were linked with disability retirement data until the end of 2010, obtained from the Finnish Centre for Pensions registers (N=6042). Sleep duration and self-reported insomnia symptoms (non-restorative sleep and difficulties in initiating and maintaining sleep) were derived from the baseline surveys. All-cause disability retirement (N=561) and the most prevalent diagnostic groups – musculoskeletal diseases (43%) and mental disorders (26%) – were examined. Cox regression analysis was used to yield hazard ratios (HR) with 95% confidence intervals (95% CI). RESULTS: A joint association of sleep duration and insomnia symptoms with disability retirement was found, implying a higher risk for those with frequent insomnia symptoms. HR for all-cause disability retirement ranged among those with frequent symptoms from 2.02 (95% CI 1.53–2.68, sleeping 7 hours) to 3.92 (95% CI 2.57–5.97, sleeping ≤5 hours). Adjusting for sociodemographic, work, and health-related factors attenuated the associations, which nevertheless remained. The associations were similar for the two diagnostic groups, although stronger for those with mental disorders. CONCLUSION: Frequent insomnia symptoms dominate the joint association of sleep duration and insomnia symptoms with subsequent disability retirement. Examining exclusively sleep duration would provide an incomplete understanding of the consequences of poor sleep.

OBJECTIVES: The aim of this study was to assess the effects of personal and work-related factors on the incidence of rotator cuff syndrome (RCS) in a large working population. METHODS: A total of 3710 French workers were included in a cross-sectional study in 2002–2005. All completed a self-administered questionnaire about personal factors and work exposure. Using a standardized physical examination, occupational physicians established a diagnosis of RCS. Between 2007–2010, 1611 workers were re-examined. Associations between RCS and risk factors at baseline were analyzed by logistic regression. RESULTS: A total of 839 men and 617 women without RCS at baseline were eligible for analysis. RCS was diagnosed in 51 men (6.1%) and 45 women (7.3%). The risk of RCS increased with age for both genders [odds ratio (OR) 4.7 (95% confidence interval [95% CI] 2.2–10.0) for men aged 45–49 years and 5.4 (95% CI 2.3–13.2) for women aged 50–59 years; reference

OBJECTIVES: The purpose of this study was to assess the effects of early part-time sick leave on return to work (RTW) and sickness absence among patients with musculoskeletal disorders. Methods A randomized controlled trial was conducted in six occupational health units of medium- and large-size enterprises. Patients aged 18–60 years with musculoskeletal disorders (N=63) unable to perform their regular work were randomly allocated to part- or full-time sick leave. In the former group, workload was reduced by restricting work time by about a half. Remaining work tasks were modified when necessary, as specified in a “fit note” from the physician. The main outcomes were time to return to regular work activities and sickness absence during 12-month follow-up. RESULTS: Time to RTW sustained for ≥4 weeks was shorter in the intervention group (median 12 versus 20 days, P=0.10). Hazard ratio of RTW adjusted for age was 1.60 [95% confidence interval (95% CI) 0.98–2.63] and 1.76 (95% CI 1.21–2.56) after further adjustment for pain interference with sleep and previous sickness absence at baseline. Total sickness absence during the 12-month follow-up was about 20% lower in the intervention than the control group. Compliance with the intervention was high with no discontinuations of part-time sick leave due to musculoskeletal reasons. CONCLUSIONS: Early part-time sick leave may provide a faster and more sustainable return to regular duties than full-time sick leave among patients with musculoskeletal disorders. This is the first study to show that work participation can be safely increased with early part-time sick leave.

OBJECTIVES: The mechanisms through which a low socioeconomic position leads to disability retirement are not yet established. We examined, on the one hand, the associations between occupational social class and disability retirement due to all causes, musculoskeletal diseases, and mental disorders and, on the other hand, the contribution of health behaviors and working conditions to these associations. METHODS: Middle-aged municipal employees from the Helsinki Health Study cohort baseline surveys in 2000–2002 (N=6516) were followed up until the end of 2010 for disability retirement. Retirement data were obtained from the registers of the Finnish Centre for Pensions and social class and covariates from the baseline surveys. Social class was categorized into managers and professionals, semi-professionals, routine non-manual employees, and manual workers. Cox regression analysis was used to calculate hazard ratios and their 95% confidence intervals. RESULTS: The risk of disability retirement was generally higher among those in lower social classes with a strong gradient for all causes, an even stronger gradient for musculoskeletal diseases, and a weaker non-linear association for mental disorders. These associations were largely mediated through physical workload among both women and men and hazardous exposures particularly among men. In mental disorders, job control also mediated the association. Strenuous desktop work and job demands widened the social class differences particularly among men and in mental disorders. The contribution of health behaviors was modest. CONCLUSIONS: Improvements particularly in the physical working conditions but also the job control of those in lower social classes are likely to reduce socioeconomic differences in disability retirement.

OBJECTIVE: Rotator cuff syndrome (RCS) is a major health problem among workers. The aim of the study was to examine the risk factors for RCS among workers exposed to various levels of shoulder constraints. METHODS: From 3710 workers, representative of a French region`s working population, trained occupational physicians diagnosed a total of 142 cases of RCS among men and 132 among women between 2002–2005. Diagnoses were established by standardized physical examination while personal factors and work exposure were assessed by self-administered questionnaires. Statistical associations between RCS and personal and work-related factors were analyzed for each gender using logistic regression modeling. RESULTS: The personal risk factors for RCS were age [odds ratio (OR) for 1-year increment 1.07, 95% confidence interval (95% CI) 1.05–1.09, among men and 1.08, 95% CI 1.06–1.10, among women] and diabetes mellitus (OR 2.9, 95% CI 1.0–8.6, among women). The work-related risk factors were (i) sustained or repeated arm abduction (≥2 hours/day) >90 degrees among men (OR 2.3, 95% CI 1.3–3.9) and >60 degrees among women (OR 1.8, 95% CI 1.0–3.2) or both conditions among men (OR 2.0, 95% CI 1.1–3.7) and women (OR 3.6, 95% CI 1.8–7.3); (ii) high repetitiveness of the task (≥4 hours/day) among men (OR 1.6, 95% CI 1.0–2.4) and women (OR 1.7, 95% CI 1.1–2.5); (iii) high perceived physical demand among men (OR 2.0, 95% CI 1.3–3.1); (iv) high psychological demand among men (OR 1.7, 95% CI 1.2–2.5); and (v) low decision authority among women (OR 1.5, 95% CI 1.0–2.3). CONCLUSION: Personal (ie, age) and work-related physical (ie, arm abduction) and psychosocial factors were associated with RCS for both genders in this working population.

In this issue of the Scandinavian Journal of Work, Environment & Health, Farioli et al (1) describe that wealthier populations report more back and neck pain than poorer populations, contradicting the well-established consensus on presence and nature of socioeconomic differences in health. Their evidence is based on an analysis of the variation in prevalence of musculoskeletal pain across 34 European countries. The authors suggest that back pain is related to affluence, on the one hand, and culturally determined health beliefs, on the other hand. When this ecological association reflects causality at the individual level, current primary prevention strategies for musculoskeletal disorders must be completely overhauled. What could explain these remarkable findings of Farioli and colleagues? Socioeconomic inequalities in health are well documented in all Western countries. Almost all important health problems and major causes of premature mortality are more common among persons with lower education, income, and occupational class. Typically, workers in manual jobs have 1.5 to 2-fold higher death rates than those in non-manual jobs and these inequalities are even larger when comparing unskilled workers with professionals (2). Similar differences are reported for self-assessed health, chronic conditions, and perceived disability. Most chronic diseases have a substantially higher prevalence in lower educational groups, but, interestingly for back disorders, only modest health inequalities have been reported (3). A recent study in the general working population in Oslo, Norway, reported marked socioeconomic gradients between lower occupational class and higher prevalence of musculoskeletal pain. Inequalities were larger among men than women and more pronounced for low-back and arm than for neck-shoulder pain. Physical job demands explained a substantial proportion of the absolute occupational class inequalities in low-back pain, while job autonomy was more important in explaining the inequalities in neck-shoulder and arm pain (4). In the GAZEL cohort of French workers, the prevalence of low-back pain lasting >30 days was significantly higher among blue-collar workers than their managers. Socioeconomic disparities reduced substantially after adjustment for mechanical load (5). In summary, all available evidence suggests a strong association between wealth and health: health determines wealth through a selection process and wealth influences health through a causation process (6). An important issue to consider is whether the presented associations suffer from the “ecological fallacy” whereby associations observed between characteristics of populations do not have relevance for associations at the individual level (7). In other words, trends across countries may be different from those within each country. Interestingly, Farioli and colleagues (1) present some evidence in their analyses for the existence of this ecological fallacy. For both back and neck pain, the prevalence was somewhat higher among workers in lower occupational classes. After adjustment for educational level and occupation, no association was apparent with socioeconomic class. Thus, the analysis with individual data shows no health inequalities, whereas the comparison at country level shows reversed health inequalities. Farioli et al’s other explanation for their findings was that back pain is culturally determined. It is not unreasonable to assume such a psychological mechanism behind the high prevalence of back and neck pain. Already in the 1950s, Mechanic (8) found that symptom expression and healthcare-seeking behavior was highly influenced by cultural factors. In the 1960s, Engel (9) proposed the biopsychosocial model of healthcare that Waddell effectively applied to back pain in the 1980s (10). Psychological factors could play a causal role in back pain development, but it is more conceivable that they influence persistence of pain and occurrence and persistence of disability. The problem is that the available evidence is not in line with a simple psychological model. For example, a review of nine cohort studies concluded that there was little evidence to link fear avoidance with poor prognosis of back pain (11). Also, the finding in Farioli’s study that the highest prevalence of neck or upper-limb symptoms was reported in Finland does not seem in line with the psychological or cultural explanation. There is no indication that Finns are overly expressive about health symptoms or in healthcare-seeking behavior. It is also difficult to imagine how we should act upon this knowledge. Should a high prevalence of back or neck pain be simply disregarded as culturally determined health beliefs or should Finns be told to complain less? One of the pitfalls in back pain research is that both back pain and its exposures can be simply assessed by a questionnaire. However, most of these measurements provide reliable and valid estimates of neither exposure nor outcome. In our view, this is one of the most important reasons for the continuing controversy about the causes of back pain, with some authors negating an association and others advocating important associations with work. In general, good evidence of a causal relation between factors at work and health outcomes requires a clear assessment of exposure, an unambiguous case definition of the disease at hand, and several well-conducted epidemiological studies to underpin the relation between exposure and health outcome (12). The measurement of low-back pain is a daunting task because there is no generally accepted case definition and there are many dimensions that affect its severity such as the intensity, frequency, and duration of pain, presence of radiation, and disability. Hoy et al (13) recently systematically reviewed studies that reported prevalence of back pain. They found a mean one-year back pain prevalence of 38% with a standard deviation of 19.4% indicating a wide variation across populations. They also found that five of ten methodological factors significantly influenced the reported prevalence. Therefore, it seems that asking persons “Did you suffer from back pain last year?” does not seem to be a very reliable measure of back pain. Dionne et al (14) proposed a minimal case definition of back pain as “back pain in the past four weeks that limited activities or daily routine”, based on a consensus of experts. They advocated the use of a broader definition that incorporated more of the elements mentioned above. It seems that we can still improve here. From the preventive point of view, the high prevalence of back and neck pain reported by Farioli et al seems to confirm the idea that we are not doing very well with back pain. Also other studies indicate that pain rates seem to be stable or rising over time (15). At the moment, the only feasible preventive measure seems to be to decrease exposure to biomechanical risk factors. However, this is neither a simple task because decreasing biomechanical exposure comes, very often, at the expense of productivity. There is still a long way to go both in terms of research methods and developing and evaluating intervention strategies for prevention of back pain.