Prediction models to identify workers at risk of sick leave due to low-back pain in the Dutch construction industry.

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.

Psychological distress screener for risk of future mental sickness absence in non-sicklisted employees.

BACKGROUND: Recently, a three-item screener, derived from the 16-item distress scale of the Four-Dimensional Symptom Checklist (4DSQ), was used to measure psychological distress in sicklisted employees. The aim of the present study was to investigate the ability of the 16-item distress scale and three-item distress screener to identify non-sicklisted employees at risk of sickness absence (SA) due to mental disorders. METHODS: Prospective cohort study including 4877 employees working in distribution and transport. The 4DSQ distress scale was distributed at baseline in November 2010. SA diagnosed within the International Classification of Diseases -10 chapter F was defined as mental SA and retrieved from an occupational health register during 2-year follow-up. The area under the receiver operating characteristic curve (AUC) was used to discriminate between workers with ('cases') and without ('non-cases') mental SA during follow-up. RESULTS: A total of 2782 employees (57%) were included in complete cases analysis; 73 employees had mental SA during 2-year follow-up. Discrimination between cases and non-cases was similar for the 16-item distress scale (AUC = 0.721; 95% CI, 0.622-0.823) and the three-item screener (AUC = 0.715; 95% CI, 0.615-0.815). CONCLUSION: Healthcare providers could use the three-item distress screener to identify non-sicklisted employees at risk of future mental SA.

Shortened version of the work ability index to identify workers at risk of long-term sickness absence.

BACKGROUND: The Work Ability Index (WAI) identifies non-sicklisted workers at risk of future long-term sickness absence (LTSA). The WAI is a complicated instrument and inconvenient for use in large-scale surveys. We investigated whether shortened versions of the WAI identify non-sicklisted workers at risk of LTSA. METHODS: Prospective study including two samples of non-sicklisted workers participating in occupational health checks between 2010 and 2012. A heterogeneous development sample (N= 2899) was used to estimate logistic regression coefficients for the complete WAI, a shortened WAI version without the list of diseases, and single-item Work Ability Score (WAS). These three instruments were calibrated for predictions of different (≥2, ≥4 and ≥6 weeks) LTSA durations in a validation sample of non-sicklisted workers (N= 3049) employed at a steel mill, differentiating between manual (N= 1710) and non-manual (N= 1339) workers. The discriminative ability was investigated by receiver operating characteristic analysis. RESULTS: All three instruments under-predicted the LTSA risks in both manual and non-manual workers. The complete WAI discriminated between individuals at high and low risk of LTSA ≥2, ≥4 and ≥6 weeks in manual and non-manual workers. Risk predictions and discrimination by the shortened WAI without the list of diseases were as good as the complete WAI. The WAS showed poorer discrimination in manual and non-manual workers. CONCLUSIONS: The WAI without the list of diseases is a good alternative to the complete WAI to identify non-sicklisted workers at risk of future LTSA durations ≥2, ≥4 and ≥6 weeks.

Mental health symptoms identify workers at risk of long-term sickness absence due to mental disorders: prospective cohort study with 2-year follow-up.

BACKGROUND: Mental health problems are a leading cause of long-term sickness absence (LTSA). Workers at risk of mental LTSA should preferably be identified before they report sick. The objective of this study was to examine mental health symptoms as predictors of future mental LTSA in non-sicklisted workers. METHODS: Prospective cohort study of 4877 non-sicklisted postal workers. Mental health symptoms were measured at baseline in November 2010 with the Four-Dimensional Symptom Questionnaire (distress and depressed mood) and Maslach's Burnout Inventory (fatigue). Mental health symptom scores were analyzed against incident mental LTSA retrieved from an occupational health register in 2011 and 2012. The area under the receiver operating characteristic curve (AUC) represented the ability of mental health symptom scores to discriminate between workers with and without mental LTSA during 2-year follow-up. RESULTS: Complete cases analysis included 2782 (57 %) postal workers of whom 73 had mental LTSA during 2-year follow-up. Distress fairly (AUC = 0.75; 95 % CI 0.67-0.82) and both depressed mood (AUC = 0.64; 95 % CI 0.57-0.72) and fatigue (AUC = 0.61; 95 % CI 0.53-0.69) poorly discriminated between workers with and without mental LTSA during 2-year follow-up. The discriminative ability of distress did not improve by adding depressed mood and fatigue. CONCLUSIONS: Measurement of distress sufficed to identify non-sicklisted postal workers at risk of future mental LTSA. The Four-Dimensional Symptom Questionnaire distress scale is a promising tool to screen working populations for of mental LTSA, which enables secondary preventive strategies.

Re: Amelsvoort et al. "Approaches for predicting long-term sickness absence".

We would like to thank Van Amelsvoort et al (1) for the interest in our study (2) and take the opportunity to clarify here that none of the workers were sick-listed when they participated in the baseline health survey. We mentioned in the abstract that incident (ie, not prevalent) long-term sickness absence was retrieved from an occupational health register (2). Our explanation of how to interpret the area under the receiver operating characteristic (ROC) curve as measure of discrimination between workers with and without long-term sickness absence might have given the impression that the study population was a mix of workers with and without sickness absence. Throughout the paper, however, workers with long-term sickness absence refer to those not sick-listed at baseline who had incident long-term sickness absence during 1-year follow-up. We agree with the authors that instruments to predict long-term sickness absence for workers still at work (secondary prevention) should be distinguished from instruments for workers already on sick leave (tertiary prevention). The objective of our study was to investigate the Work Ability Index (WAI) as an instrument to predict future long-term sickness absence in non-sick-listed workers, ie, as an instrument for secondary prevention. Therefore, the term "screening" was used in the appropriate context. Van Amelsvoort et al (1) raise an interesting point when they state that including the outcome (sickness absence) as predictor in the model will shift the focus towards the prediction of recurrent sickness absence. Obviously, sickness absence is useless for predicting the first long-term sickness absence episode of an individual who has just finished education and enters the workforce. During working life, workers develop a sickness absence history either without sickness absence episodes (ie, zero-absenteeism) or with successive sickness absence episodes. In the latter case, Navarro et al (3) recommended to use statistical techniques for recurrent rather than independent events. A worker's sickness absence history is the strongest predictor of future sickness absence episodes (4, 5). From that perspective, it would be a missed opportunity not to include past sickness absence as variable in prediction models for future long-term sickness absence.

Screening manual and office workers for risk of long-term sickness absence: cut-off points for the Work Ability Index.

OBJECTIVES: The aim of this study was to investigate the Work Ability Index (WAI) as a tool to screen for risk of different durations of long-term sickness absence (LTSA) among manual and office workers. METHODS: The prospective study comprised a cohort of 3049 (1710 manual and 1339 office) workers participating in occupational health surveys between 2010-2012. The survey date was set as baseline and incident LTSA episodes of different duration (>14, >28, >42, >60, and >90 days) were retrieved from an occupational health register in the year following the survey. Baseline WAI scores were associated with LTSA episodes occurring (no/yes) during one-year follow-up by logistic regression analysis in a random sample (N=1000) of the cohort. Predictions of LTSA risk were then validated among the workers not included in the random sample. RESULTS: The odds of LTSA episodes at follow-up decreased with increasing baseline WAI scores (ie, better work ability). The WAI accurately predicted the risk of future LTSA episodes >28, >42, >60 days, but over-predicted the risk of LTSA episodes >14 and >90 days. The WAI discriminated between workers at high and low risk of LTSA episodes of all durations. Office workers had higher WAI scores than manual workers. Consequently, false-negative rates were higher among office workers and false-positive rates were higher among manual workers at each WAI cut-off point. CONCLUSION: The WAI could be used to screen both manual and office workers for risk of LTSA episodes lasting >28, >42, >60 days. WAI cut-off points depend on the objectives of screening and may differ for manual and office workers.

Effectiveness of an intervention at construction worksites on work engagement, social support, physical workload, and need for recovery: results from a cluster randomized controlled trial.

BACKGROUND: To prolong sustainable healthy working lives of construction workers, a worksite prevention program was developed which aimed to improve the health and work ability of construction workers. The aim of the current study was to investigate the effectiveness of this program on social support at work, work engagement, physical workload and need for recovery. METHODS: Fifteen departments from six construction companies participated in this cluster randomized controlled trial; 8 departments (n=171 workers) were randomized to an intervention group and 7 departments (n=122 workers) to a control group. The intervention consisted of two individual training sessions of a physical therapist to lower the physical workload, a Rest-Break tool to improve the balance between work and recovery, and two empowerment training sessions to increase the influence of the construction workers at the worksite. Data on work engagement, social support at work, physical workload, and need for recovery were collected at baseline, and at three, six and 12 months after the start of the intervention using questionnaires. RESULTS: No differences between the intervention and control group were found for work engagement, social support at work, and need for recovery. At 6 months follow-up, the control group reported a small but statistically significant reduction of physical workload. CONCLUSION: The intervention neither improved social support nor work engagement, nor was it effective in reducing the physical workload and need for recovery among construction workers. TRIAL REGISTRATION: NTR1278.

Enterprise restructuring and the health of employees: a cohort study.

OBJECTIVE: To examine the influence of enterprise restructuring on general health and emotional exhaustion, and to investigate which factors explain the relation between restructuring and these outcomes. METHODS: Longitudinal data of the Netherlands Working Conditions Cohort Study were used. At baseline and after 12 months, 9076 employees filled out a questionnaire. Logistic regression analysis was applied. RESULTS: Prolonged exposure to restructuring increased the likelihood of poor general health, and its influence was partly explained by job insecurity. Emotional exhaustion was more likely among employees that experienced prolonged exposure to restructuring or restructuring during the past year. Job insecurity explained the influence of prolonged restructuring, together with job demands and supervisor's support. CONCLUSIONS: Prolonged exposure to restructuring adversely affects general health and emotional exhaustion in employees, and its influence seems to be explained by job insecurity.

Meeting the challenges of implementing an intervention to promote work ability and health-related quality of life at construction worksites: a process evaluation.

OBJECTIVE: To evaluate the process of a prevention program among construction workers. METHODS: The program consisted of training sessions of a physical therapist and an empowerment trainer, and a Rest-Break Tool. Data on seven process items were collected by means of questionnaires and interviews. RESULTS: Recruiting construction companies to participate was difficult. The therapists and trainer largely provided the training sessions as intended, but the Rest-Break Tool was poorly implemented. Construction workers (n = 171) showed high reach (84%) and moderate attendance rates (three of four sessions). Sixty-four percent of the construction workers recommended the overall program to colleagues. Company size, economic recession, engagement of the management, and intervention year influenced dose delivered and satisfaction. CONCLUSIONS: The study showed a successful reach, dose and fidelity, and moderate satisfaction. Furthermore, contextual factors played an important role during the implementation.

Intervention Mapping as a framework for developing an intervention at the worksite for older construction workers.

PURPOSE: The purpose of this study was to apply the Intervention Mapping approach as a framework in the development of a worksite intervention to improve the work ability of construction workers. DESIGN: Development of an intervention by using the Intervention Mapping approach. SETTING: Construction worksite. PARTICIPANTS: Construction workers aged 45 years and older. MEASURES AND ANALYSIS: According to the principles of Intervention Mapping, evidence from the literature was combined with data collected from stakeholders (e.g., construction workers, managers, providers). RESULTS: The Intervention Mapping approach resulted in an intervention with the following components: (1) two individual visits of a physical therapist to lower the physical workload, (2) a Rest-Break tool to improve the balance between work and recovery, and (3) two empowerment training sessions to increase the range of influence at the worksite. CONCLUSIONS: Application of Intervention Mapping in the development of a worksite prevention program was useful in the construction industry to obtain a positive attitude and commitment. Stakeholders could give input regarding the program components as well as provide specific leads for the practical intervention strategy. Moreover, it also gives insight in the current theoretical and empirical knowledge in the field of improving the work ability of older workers in the construction industry.

A worksite prevention program for construction workers: design of a randomized controlled trial.

BACKGROUND: A worksite prevention program was developed to promote the work ability of construction workers and thereby prolong a healthy working life. The objective of this paper is to present the design of a randomized controlled trial evaluating the effectiveness of that intervention program compared with usual care for construction workers. METHODS: The study is designed as a randomized controlled trial with a follow-up of one year. Employees eligible for this study are construction workers performing actual construction work. The worksite intervention will be compared with usual care. This intervention was developed by using the Intervention Mapping approach and consists of the following components: (1) two individual training sessions of a physical therapist to lower the physical workload, (2) a Rest-Break tool to improve the balance between work and recovery, and (3) two empowerment training sessions to increase the influence of the construction workers at the worksite. Outcome measures are assessed at baseline, 3, 6, and 12 months. The primary outcome measures of this study are work ability and health-related quality of life. Secondary outcome measures include need for recovery, musculoskeletal complaints, work engagement and self efficacy. Cost-effectiveness will be evaluated from the company perspective. Moreover, a process evaluation will be conducted. DISCUSSION: The feasibility of the intervention and the study has been enhanced by creating an intervention program that explicitly appeals to construction workers and will not interfere too much with the ongoing construction. The feasibility and effectiveness of this worksite prevention program will be investigated by means of an effect- and a process evaluation. If proven effective, this worksite prevention program can be implemented on a larger scale within the construction industry. TRIAL REGISTRATION: NTR1278.

Can favorable psychosocial work conditions and high work dedication protect against the occurrence of work-related musculoskeletal disorders?

OBJECTIVES: This study investigated whether work dedication and job resources are longitudinally related to work-related musculoskeletal disorders and whether job resources buffer the impact of job demands on these disorders? METHODS: Data were used from a longitudinal three-phase study (2004, 2005, 2006) on health at work among a sample of Dutch workers. The first survey was sent in 2004 by e-mail to 3100 members of an existing panel. For the analyses, 1522 participants were included with full longitudinal data. The analyses were performed using an autoregressive model with generalized estimating equations. RESULTS: The job-resource quality of communication was found to predict the risk of work-related musculoskeletal disorders over time. This effect was not mediated by work dedication. A high quality of communication was also found to buffer the negative effects of a high physical workload on the risk of work-related musculoskeletal disorders. Furthermore, a low level of social support by colleagues was found to buffer the negative effect of a medium physical workload on work-related musculoskeletal disorders. CONCLUSIONS: This study shows that job resources are not only important for promoting work dedication, but may also moderate the negative impact of high job demands on the risk of work-related musculoskeletal disorders. With respect to social support, the question is raised of whether this can also work negatively. The results of this study imply that, besides avoiding or reducing risks to health in the workplace and lowering job demands, strengthening job resources may additionally buffer harmful effects of job demands on musculoskeletal health.

Evaluation of the effects of a training programme for patients with prolonged fatigue on physiological parameters and fatigue complaints.

OBJECTIVES: Complaints of prolonged fatigue are considered as a major health problem, as it can affect daily functioning and may lead to work disability. To increase knowledge about the effectiveness of interventions focussing on fatigued patients, a study was designed to evaluate an established training programme for patients with prolonged fatigue. MATERIALS AND METHODS: Eighteen patients who reported fatigue to be one of their major health complaints and who were suffering from functional impairments attended a training programme of six weeks, three times a week. The training consisted mainly of physical endurance training, relaxation therapy and breathing exercises in rest. At baseline, time- and frequency-domain measures of heart rate variability (HRV) and respiration rate measurements were recorded during rest and during recovery after bicycle exercise. Furthermore, fatigue complaints were assessed with the Checklist Individual Strength (CIS). These measurements were repeated at three weeks and six weeks from baseline. RESULTS: After three weeks, HRV increased significantly in rest--SDNN, i.e. standard deviation of normal beat-to-beat intervals (p = 0.02), very low frequency (p = 0.04) and low frequency (p = 0.04)--and showed a positive trend in the remaining HRV components. No significant HRV changes during recovery were found. Respiration rate decreased significantly after six weeks during rest (from 11.8, SD = 4.65 to 8.1, SD = 2.57 b x min-1) and during recovery (from 15.1, SD = 4.90 to 10.4, SD = 2.97 b x min-1). In all patients, CIS scores decreased after six weeks training (from 106, SD = 13.3 to 78, SD = 21.8, p = 0.001). CONCLUSIONS: The results suggest that a six-week training programme has a beneficial effect on physiological and subjective parameters in patients with severe complaints of fatigue.

Treatment inferred disease severity in Crohn's disease: evidence for a European gradient of disease course.

OBJECTIVE: Geographic differences in disease course of Crohn's disease (CD) might possibly be related to differences in genetic and environmental factors encountered in different parts of the world. The aim of this study was to assess differences in treatment regimens within a European cohort of CD patients as a reflection of disease course, and to identify associated phenotypic risk factors at diagnosis. MATERIAL AND METHODS: A prospective European population-based inception cohort of 380 CD patients was studied. The patients were classified for phenotype according to the Vienna classification. Differences between Northern and Southern European centres in treatment over the first 10 years of disease were analysed using a competing risks survival analysis method. RESULTS: Patients in the North were more likely to have had surgery (p<0.01), whereas patients in the South were more likely to have been treated medically (p<0.01). Phenotype at diagnosis was not predictive of differences in treatment regimens between North and South. CONCLUSIONS: In this study, a difference in management of CD was observed between Northern and Southern European centres. This suggests that there may be a North-South disease severity gradient across Europe. Phenotypic differences between patients in the North and South did not explain this observed difference.

Duration dependence in sickness absence: how can we optimize disability management intervention strategies?

OBJECTIVE: The optimal timing of interventions during sickness absence remains difficult to determine, because we do not have a clear picture of the presence and type of duration dependence that exists. This study investigates the impact of an intervention by the occupational physician as well as of socioeconomic and work-related factors on duration dependence during sickness absence. METHODS: Analyses were performed at the population level using data from a major longitudinal survey on work incapacity and return to work in The Netherlands. Several models of duration dependence are estimated. RESULTS: Evidence is found for the presence of variable-duration dependence. Characteristics that influence duration dependence of the return-to-work (RTW) rate are identified. CONCLUSIONS: The findings imply that RTW intervention strategies should vary according to differences in workers' susceptibility to positive or negative duration-dependence effects.

Modelling return-to-work intervention strategies: a method to help target interventions.

The aim of this study is twofold: 1) to investigate the relationship between the probability of receiving an intervention by the occupational physician and the probability of return-to-work (RTW) of sick workers; 2) to explore the use of simultaneous modelling of the intervention and RTW process. Analyses are performed on population level using data from a major longitudinal survey on work incapacity and RTW in the Netherlands. A bivariate probit model is used to estimate the correlation between the probability of intervention and the probability of RTW A bivariate hazard model is applied to explore the joint distribution of the waiting times for the intervention and RTW The results of this study show that the probability of receiving an intervention from the occupational physician is not correlated with the probability of RTW Neither is the timing of both events correlated. The analyses do not indicate that the intervention by the occupational physician provides incentives for sick workers to RTW quicker.

Waiting for the doctor: gender differences in the timing of an intervention by the occupational physician.

This study aims to answer the question whether the relatively high inflow risk into disability for women, compared to that for men, is related to a lower chance of being called by the occupational physician during sickness absence. This chance is influenced by sociodemographic, health-related, and work-related factors, as well as by the duration of sickness absence. Using a proportional hazards model, the "risk" of being called by the physician within a certain time period (the so-called hazard rate) is estimated. Kaplan-Meier curves show a gender difference in the hazard rate. Women appear to have a higher chance of being called by the occupational physician (i.e., a shorter waiting time). The influence of the covariates on the hazard rate is estimated using a Weibull model. The Weibull estimations show a negative duration dependence for women, while for men there is no duration dependence. It is concluded that the higher chance for women to be called by the occupational physician is not associated with a gender difference in treatment. Rather, it is the result of a difference in underlying characteristics. Underlying characteristics that significantly predict the waiting time for the occupational physician are in particular related to the labor market position of the employee: educational qualifications, firm size, industry, occupational workload, and job tenure. Other significant predictors are duration and diagnosis.

Taking a new course in research on the effectiveness of interventions. A study of physiotherapy interventions for people with musculoskeletal complaints.

Physiotherapy is a commonly employed intervention for people with musculoskeletal complaints. However, due to (methodological) limitations in previous research, the effectiveness of physiotherapy interventions has not yet been proven. The aim of the present study is twofold. First we try to solve some of the methodological problems, of which the most important are selection and endogeneity biases and state dependence. Secondly, the effect of a physiotherapy intervention on recovery from musculoskeletal complaints is investigated. The probability of receiving a physiotherapy intervention is estimated, as well as the probability of recovery as a result of this intervention. A longitudinal design is used. Analyses are performed using secondary data on a populational level. The analytical framework is provided by a Markov model. We use a logit model to estimate transition probabilities of this Markov model. Results show that experience with physiotherapy in the past is an important predictor for receiving physiotherapy in the future. Other predictors of the chance of receiving an intervention are also identified. Furthermore, results indicate that the effect of a physiotherapy intervention on recovery is negative. It is concluded that both the latter effect and the effect of intervention experience can partly be explained by medicalization, in spite of a presence of "severe" cases in the intervention group.