Falk Liebers

Musculoskeletal symptoms of the upper extremities and the neck: A cross-sectional study on prevalence and symptom-predicting factors at visual display terminal (VDT) workstations

BackgroundThe aim of this study was to determine the prevalence and the predictors of musculoskeletal symptoms in the upper extremities and neck at visual display terminal (VDT) workstations.MethodsIn a cross-sectional study 1,065 employees working at VDT > 1 h/d completed a standardised questionnaire. Workstation conditions were documented in a standardised checklist, and a subgroup of 82 employees underwent a physical examination.ResultsUsing the Nordic Questionnaire, the 12-month prevalence of symptoms of the neck, shoulder region, hand/wrist, or elbow/lower arm was 55%, 38%, 21%, and 15% respectively. The duration of VDT work had a significant impact on the frequency of neck symptoms in employees performing such work > 6 h/d.ConclusionWith regard to musculoskeletal symptoms of the upper extremities, preventive measures at VDT workstations should be focused on neck and shoulder symptoms (e.g. ergonomic measures, breaks to avoid sitting over long periods).

Individual and occupational risk factors for knee osteoarthritis: results of a case-control study in Germany

IntroductionA number of occupational risk factors are discussed in relation to the development and progress of knee joint diseases (for example, working in a kneeling or squatting posture, lifting and carrying heavy weights). Besides the occupational factors, a number of individual risk factors are important. The distinction between work-related and other factors is crucial in assessing the risk and in deriving preventive measures in occupational health.MethodsIn a case-control study, patients with and without symptomatic knee osteoarthritis (OA) were questioned by means of a standardised questionnaire complemented by a semi-standardised interview. Controls were matched and assigned to the cases by gender and age. Conditional logistic regression was used in analysing data.ResultsIn total, 739 cases and 571 controls were included in the study. In women and men, several individual and occupational predictors for knee OA could be described: obesity (odds ratio (OR) up to 17.65 in women and up to 12.56 in men); kneeling/squatting (women, OR 2.52 (>8,934 hours/life); men, 2.16 (574 to 12,244 hours/life), 2.47 (>12,244 hours/life)); genetic predisposition (women, OR 2.17; men, OR 2.37); and sports with a risk of unapparent trauma (women, OR 2.47 (≥1,440 hours/life); men, 2.58 (≥3,232 hours/life)). In women, malalignment of the knee (OR 11.54), pain in the knee already in childhood (OR 2.08), and the daily lifting and carrying of loads (≥1,088 tons/life, OR 2.13) were related to an increased OR; sitting and smoking led to a reduced OR.ConclusionsThe results support a dose-response relationship between kneeling/squatting and symptomatic knee OA in men and, for the first time, in women. The results concerning general and occupational predictors for knee OA reflect the findings from the literature quite well. Yet occupational risks such as jumping or climbing stairs/ladders, as discussed in the literature, did not correlate with symptomatic knee OA in the present study. With regards to occupational health, prevention measures should focus on the reduction of kneeling activities and the lifting and carrying of loads as well as general risk factors, most notably the reduction of obesity. More intervention studies of the effectiveness of tools and working methods for reducing knee straining activities are needed.

The effects of working height and manipulated weights on subjective strain, body posture and muscular activity of milking parlor operatives--laboratory study.

The incidence of work-related musculoskeletal disorders among milking parlor operatives has increased while milking parlors were getting bigger. At the same time parlor design was improved regarding the physical load as well as body postures. In contrast to former studies on workload in parlor milking this project was designed and performed as an experimental study in a laboratory setting including 6 female subjects. Motion analysis and psycho-physiological analysis (EMG, heart rate, subjective perceived strain index) were carried out. Intra-individual comparisons were made for the different settings using general linear models for repeated measurements. The effects of working height and weight of milking unit during parlor milking were investigated regarding the impact on muscular load and body posture. The results showed that the optimal working height for attaching the cluster is having the teats at shoulder level of the parlor operative. Another important workload reduction was achieved by reducing the weight of the milking cluster. The named discomfort, localized fatigue and the body posture analysis provide evidence that the changes in modern milking parlors due to mechanization still bear the risk of overburden for the worker.

Individual and occupational risk factors for knee osteoarthritis – Study protocol of a case control study

BackgroundKnee osteoarthritis (OA) is one of the frequent and functionally impairing disorders of the musculoskeletal system. In the literature, a number of occupational risk factors are discussed as being related to the development and progress of knee joint diseases, e.g. working in kneeling or squatting posture, lifting and carrying of heavy weights. The importance of the single risk factors and the possibility of prevention are currently under discussion. Besides the occupational factors, a number of individual risk factors are important, too. The distinction between work-related factors and individual factors is crucial in assessing the risk and in deriving preventive measures in occupational health. In existing studies, the occupational stress is determined mainly by surveys in employees and/or by making assumptions about individual occupations. Direct evaluation of occupational exposure has been performed only exceptionally.The aim of the research project ArGon is the assessment of different occupational factors in relation to individual factors (e.g. constitutional factors, leisure time activities, sports), which might influence the development and/or progression of knee (OA). The project is designed as a case control study.Methods/DesignTo raise valid data about the physical stress associated with occupational and leisure time activities, patients with and without knee OA are questioned by means of a standardised questionnaire and an interview. The required sample size was estimated to 800 cases and an equal number of controls. The degree and localisation of the knee cartilage or joint damages in the cases are documented on the basis of radiological, arthroscopic and/or operative findings in a patient record. Furthermore, occupational exposure is analysed at selected workplaces. To evaluate the answers provided in the questionnaire, work analysis is performed.DiscussionIn this research project, specific information on the correlation of occupational and individual factors on the one hand and the current state of knee OA on the other will be analysed in order to describe preventive measures. In addition, information regarding a better evaluation of various forms of physical stress in different occupations will be available. This might lead to more effective prevention strategies.

The Gutenberg Health Study: measuring psychosocial factors at work and predicting health and work-related outcomes with the ERI and the COPSOQ questionnaire

BackgroundSeveral instruments have been developed to assess psychosocial workload. We compared two of these instruments, the Effort-Reward Imbalance (ERI) model and the Copenhagen Psychosocial Questionnaire (COPSOQ) with regard to congruent validity and internal validity.MethodsThis analysis is based on a population-based sample of the baseline examination of 2,783 employees from the Gutenberg Health Study (GHS). About half of the participants completed the ERI questionnaire (n = 1,342), the other half completed the COPSOQ (n = 1,441). First, the two samples were compared and descriptive analyses were carried out calculating mean values for both instruments in general, then separately for age, gender and main occupational groups. Second, we analyzed the relationship between ERI and COPSOQ scales on the workplace situation and on the workplace outcomes: job satisfaction, general health, burnout, satisfaction with life, by applying stepwise logistic regression analysis.Results and discussionFor the majority of occupations, high effort as reflected by the ERI corresponded with high demands as reflected by the COPSOQ. Comparably, high reward (according to ERI) yielded a good agreement with high “influence and development” (according to COPSOQ). However, we could also find differences between ERI and COPSOQ concerning the intensity of psychosocial workload in some occupations (e.g., physicians/pharmacists or warehouse managers/warehousemen/transport workers). These differences point to differing theoretical concepts of ERI and COPSOQ. When the ability of ERI and COPSOQ was examined to determine the associations with health and work outcomes, burnout could be better predicted by the COPSOQ; this might be due to the fact that COPSOQ comprises the constructs “work-privacy conflict” and “emotional demand”, which are closely related to burnout. However, methodological differences between these instruments limit their direct comparability.ConclusionsThe ERI and COPSOQ instrument yielded similar results for most occupational groups. The slightly stronger association between psychosocial workload as assessed by COPSOQ and burnout might be explained by its broader approach. The ability of the ERI and COPSOQ instrument to reflect relevant risk factors for clinically manifest disorders (e.g., coronary heart disease) will be derived from subsequent prospective analyses of the GHS with the follow-up data.

The Key Indicator Method for Manual Handling Operations (KIM-MHO) - evaluation of a new method for the assessment of working conditions within a cross-sectional study

BackgroundUpper extremity musculoskeletal symptoms and disorders are common in the working population. The economic and social impact of such disorders is considerable. Long-time, dynamic repetitive exposure of the hand-arm system during manual handling operations (MHO) alone or in combination with static and postural effort are recognised as causes of musculoskeletal symptoms and disorders. The assessment of these manual work tasks is crucial to estimate health risks of exposed employees. For these work tasks, a new method for the assessment of the working conditions was developed by the Federal Institute for Occupational Safety and Health (BAuA) and released as a draft in the year 2007. The draft of the so-called Key Indicator Method for Manual Handling Operations (KIM-MHO) was developed in analogy with the existing KIM for Lifting/Holding/Carrying (KIM-LHC) and Pulling/Pushing (KIM-PP) of loads. The KIM-MHO is designed to fill the gap existing in risk assessment of manual work processes, since the existing KIMs deal only with manual handling of loads.This research project focused on the following:- Examination of the validity of workplace assessment with the KIM-MHO comparing expert ratings with the results of the observations.- Examination of the objectivity of workplace assessment with the KIM-MHO applied by different examiners.- Examination of the criterion validity of the risk assessment provided by KIM-MHO with respect to the association between exposure and the occurrence and prevalence of health related outcomes.Methods/DesignTo determine the objectivity and validity of workplace assessment, the KIM-MHO is applied by occupational health and safety officers at different workplaces involving manual handling operations.To determine the criterion validity of risk assessment, a survey of employees at different workplaces takes place with standardised questionnaires and interviews about symptoms in the neck and upper extremities. In addition, physical examinations of these employees following a standardised medical diagnostic procedure are also carried out.DiscussionThis research project will provide scientific evaluation of the new KIM-MHO and, if necessary, indicate areas for modification to improve this new method for assessment of the health risk of manual handling operations at diverse workplaces.

Assessment of salivary cortisol as stress marker in ambulance service personnel: comparison between shifts working on mobile intensive care unit and patient transport ambulance

PurposeThe aim of this study was to describe and compare salivary cortisol of ambulance personnel on days with different work demands as well as to correlate the individual perception of demands to the physiological outcome cortisol.MethodsDiurnal cortisol profiles on a day in emergency service and on a day in patient transport were monitored for 24 subjects working in an urban ambulance station. Changes of cortisol were also observed during 42 operations in emergency service and 24 operations in patient transport and were compared to the individual perception of physical and emotional demands.ResultsRise of cortisol in the morning on days in emergency service was significantly higher than in patient transport suggesting adjustment to forthcoming demanding tasks. There were only few situations with strong endocrine reaction in emergency service as well as in patient transport. The magnitude of this reaction was not related to the individual perception of demand.ConclusionAmbulance service personnel seem to be used to critical situations. There was few awareness of the “physiological” stress response indicating that stress is probably not perceived in work situations characterised by routines.

Potential of a Quarter Individual Milking System to Reduce the Workload in Large-Herd Dairy Operations

ABSTRACT Large-herd dairy operations utilize parlor milking systems that reduce the physical workload in comparison to tethering systems. Nevertheless, the number of musculoskeletal disorders among workers on dairy farms is not decreasing. In response, a study was carried out to measure the workload focusing on the impact of working height and weight of the milking unit. In this article a new quarter individual milking unit without claw and using single-tube guidance is compared with a light (1.4 kg) conventional unit. A significant reduction of muscular load as well as the reduction of process time was measured using the quarter individual system. Body posture was also recorded using video-based motion analysis. Based on these results, the new system is expected to significantly improve the work place in modern milking parlors by reducing extreme postures as well as the physical and static musculoskeletal load.

Evaluation of objectivity, reliability and criterion validity of the key indicator method for manual handling operations (KIM-MHO), draft 2007.

Upper extremity musculoskeletal symptoms and disorders are common in the working population. The economic and social impact of such disorders is considerable. Long-time, dynamic repetitive exposure of the hand-arm system during manual handling operations (MHO) alone or in combination with static and postural effort are recognised as causes of musculoskeletal symptoms and disorders. The assessment of these manual work tasks is crucial to estimate health risks of exposed employees. For these work tasks, a new method for the assessment of the working conditions was developed and a validation study was performed. The results suggest satisfying criterion validity and moderate objectivity of the KIM-MHO draft 2007. The method was modified and evaluated again. It is planned to release a new version of KIM-MHO in spring 2012.

The Gutenberg health study: associations between occupational and private stress factors and work-privacy conflict

BackgroundWork-privacy conflict (WPC) is no longer a rarity but constitutes a societal problem. The objectives of the present study were (1) to investigate the distribution and prevalence of WPC among the employed participants in the Gutenberg Health Study at baseline and (2) to study the dependence of WPC on a broad range of private life and occupational characteristics as well as on psychosocial working conditions.MethodsThis analysis is based on a representative, population-based sample of 3,709 employees participating in the Gutenberg Health Study. Descriptive and bivariable analyses were carried out separately for women and men. Distribution and prevalence of WPC were examined according to socio-demographic and occupational characteristics as well as psychosocial working conditions. Further, stepwise selection of Poisson log-linear regression models were performed to determine which socio-demographic and occupational characteristics were most associated with the outcome variable WPC and to obtain adjusted prevalence ratios from the final model. The multivariable analyses were conducted both separately for women and men and with all subjects together in one analysis.ResultsThere was a high prevalence of WPC in the present study (27.4 % of the men and 23.0 % of the women reported a high or very high WPC). A variety of factors was associated with WPC, e.g. full-time employment, depression and many of the psychosocial risk factors at work. Also, the multivariable results showed that women were of higher risk for a WPC.ConclusionsBy affecting the individual work life, home life, and the general well-being and health, WPC may lead to detrimental effects in employees, their families, employers, and society as a whole. Therefore, the high prevalence of WPC in our sample should be of concern. Among women, the risk for suffering from WPC was even higher, most likely due to multiple burdens.