Jason Devereux

THE NATURE OF WORK-RELATED NECK AND UPPER LIMB MUSCULOSKELETAL DISORDERS

The nature of work-related musculoskeletal disorders of the neck and upper limbs is reviewed using both scientific data and the consensus view of experts, union bodies and government agencies across the European Union. Work-related musculoskeletal disorders describe a wide range of inflammatory and degenerative diseases and disorders. These conditions result in pain and functional impairment and may affect, besides others, the neck, shoulders, elbows, forearms, wrists and hands. They are work-related when the work activities and work conditions significantly contribute to their development or exacerbation but are not necessarily the sole determinant of causation. The classification and the need for standardised diagnostic methods for assessment of neck and upper limb musculoskeletal disorders are reviewed. These disorders are a significant problem within the European Union with respect to ill health, productivity and associated costs. The pathomechanisms of musculoskeletal disorders affecting tendons, ligaments, nerves, muscle, circulation and pain perception are reviewed and conceptual models for the pathogenesis of musculoskeletal disorders affecting the neck and upper limbs are presented. The epidemiological evidence on the work-relatedness of these disorders is discussed. A relationship between the performance of work and the occurrence of neck and upper limb musculoskeletal disorders is evident. Intervention strategies in the workplace for the reduction of both exposure and effect should focus upon factors within the work organisation as well as actively involving the individual worker. The current knowledge is sufficient to enable informed decisions to be made on future research needs and prevention strategies at the societal, organisational and individual level.

Epidemiological study to investigate potential interaction between physical and psychosocial factors at work that may increase the risk of symptoms of musculoskeletal disorder of the neck and upper limb

Objectives: To investigate potential interactions between physical and psychosocial risk factors in the workplace that may be associated with symptoms of musculoskeletal disorder of the neck and upper limb. Methods: 891 of 1514 manual handlers, delivery drivers, technicians, customer services computer operators, and general office staff reported on physical and psychosocial working conditions and symptoms of neck and upper limb disorders using a self administered questionnaire (59% return rate). Of the 869 valid questionnaire respondents, 564 workers were classified in to one of four exposure groups: high physical and high psychosocial, high physical and low psychosocial, low physical and high psychosocial, and low physical and low psychosocial. Low physical and low psychosocial was used as an internal reference group. The exposure criteria were derived from the existing epidemiological literature and models for physical and psychosocial work factors. The frequency and amplitude of lifting and the duration spent sitting while experiencing vibration were used as physical exposure criteria. Ordinal values of mental demands, job control, and social support with managers and coworkers were used as psychosocial exposure criteria. Results: In the multivariate analyses, the highest and significant increase in risk was found in the high physical and high psychosocial exposure group for symptoms of hand or wrist and upper limb disorders after adjusting for years at the job, age, and sex. A potential interaction effect was found for the symptoms of the hand or wrist and upper limb disorders but not for the neck symptoms. Conclusion: This study showed that workers highly exposed to both physical and psychosocial workplace risk factors were more likely to report symptoms of musculoskeletal disorders than workers highly exposed to one or the other. The results suggest an interaction between physical and psychosocial risk factors in the workplace that increased the risk of reporting symptoms in the upper limbs. Psychosocial risk factors at work were more important when exposure to physical risk factors at work were high than when physical exposure was low. Ergonomic intervention strategies that aim to minimise the risks of work related musculoskeletal disorders of the upper limb should not only focus on physical work factors but also psychosocial work factors.

Interactions between physical and psychosocial risk factors at work increase the risk of back disorders: an epidemiological approach

OBJECTIVES: To investigate the possible interactions between physical and psychosocial risk factors at work that may be associated with self reported back disorders. METHODS: 891 of 1514 manual workers, delivery drivers, technicians, customer services computer operators, and general office staff reported risk factors at work and back disorders with a self administered questionnaire (59% return rate). Of the 869 respondents with a valid questionnaire, 638 workers were classified in to one of four exposure groups: high physical and high psychosocial; high physical and low psychosocial; low physical and high psychosocial; and low physical and low psychosocial. Low physical and low psychosocial was used as an internal reference group. The exposure criteria were derived from existing epidemiological publications and models for physical and psychosocial work factors. The frequency and amplitude of lifting and the duration spent sitting while experiencing vibration were used as physical exposure criteria. Ordinal values of mental demands, job control, and social support from managers and coworkers were used as psychosocial exposure criteria. RESULTS: The highest increase in risk was found in the high physical and high psychosocial exposure group for symptoms of back disorders. In the crude and multivariate analyses, a departure from an additive risk model was found for the 7 day prevalence of symptoms of a low back disorder and also for a recurrent back disorder not present before the current job but also experienced in the past 7 days. CONCLUSION: This study suggests that an interaction between physical and psychosocial risk factors at work may exist to increase the risk of self reported back disorders. Ergonomic prevention strategies that aim to minimise the risks of symptoms of work related back disorders should not only focus on physical but also on psychosocial risk factors at work. The greatest benefits are likely to be realised when both physical and psychosocial factors are put right.

The relationship between long-term job strain and morning and evening saliva cortisol secretion among white-collar workers.

The objective of this study was to assess long-term job strain impact on morning and evening salivary cortisol secretion. In all 77 white-collar workers (31% women; sample mean age, 42 years at baseline) volunteered to sample morning (immediately after waking up) and evening (10 p.m.) salivary cortisol for 7 consecutive days. By median split on aggregated self-reported isostrain from three consecutive questionnaires distributed in a period of approximately 3.5 years the participants were classified into a high or low long-term isostrain condition. Regardless of strain condition, there was a significant reduction in morning salivary cortisol secretion from the working week to the weekend, whereas evening salivary cortisol secretion showed no significant variation during the week. Although chronic isostrain did not affect the morning saliva cortisol measures, evening cortisol secretion was significantly elevated in the chronic high isostrain group throughout the whole week. The elevated evening cortisol measures associated with chronic high strain are concordant with the findings in other studies on long-term strain.

Comparing and combining the demand-control-support model and the effort reward imbalance model to predict long-term mental strain

A first purpose of this prospective study was to investigate whether the levels of mental strain and the working conditions included in the Effort-Reward Imbalance (ERI) model and the Demand-Control-Support (DCS) model differed for managers/professionals (n = 658) and manual workers (n = 343). An additional purpose was to compare the predictive power of the DCS and ERI models in the regard to long-term mental strain for these two groups. The study further aimed to investigate whether combining the models would improve the predictive power of long-term mental strain. Managers/professionals reported higher job demands and intrinsic efforts than did the manual workers, as well as slightly higher mental strain, but also higher decision latitude, social support, and rewards from work. Both models explained small albeit significant proportions of variance in mental strain for both occupational groups. A tentative conclusion from the study is that combining the two models may slightly increase the explanatory power to predict work-related mental strain.

The combined effect of physical, psychosocial/organisational and/or environmental risk factors on the presence of work-related musculoskeletal symptoms and its consequences.

This study assessed the combined effect of physical and psychosocial/organisational and/or environmental factors on the presence of musculoskeletal symptoms (MSS) and its consequences (reduced activities and absenteeism due to MSS) in a random sample of 3003 workers in New Zealand. By telephone interview, participants reported their current workplace exposures and MSS (neck/shoulder, arm/elbow, wrist and low back) and its consequences. Data were analysed using multivariable logistic regression. Combined exposure to physical and psychosocial/organisational and/or environmental factors increased the odds of MSS in the neck/shoulder (OR 3.14, 95% CI 1.79-5.52), arms/elbow regions (OR 4.14, 95% CI 2.21-7.76) and low back (OR 1.74, 95% CI 1.28-2.37) and its consequences, i.e. reduced activities due to neck/shoulder symptoms (OR 5.45, 95% CI 2.28-13.00), absenteeism due to neck/shoulder symptoms (OR 5.19, 95% CI 2.24-12.01) and absenteeism due to low back symptoms (OR 4.37, 95% CI 2.92-6.53). In contrast, favourable psychosocial/organisational work conditions reduced the odds of wrist symptoms due to poor physical work conditions (OR 2.19, 95% CI 1.44-3.34). We conclude that to reduce MSS and its consequences, employers need to adopt a multifaceted approach: concentrate on improving physical conditions as well as the psychosocial/organisational and environmental aspects of the working environment.

Prevalence and work-related risk factors for reduced activities and absenteeism due to low back symptoms

Although quite a lot is known about the risk factors for low back symptoms (LBS), less is known about the risk factors for the consequences of LBS. A sample of 3003 men and women randomly selected from the New Zealand Electoral Roll, were interviewed by telephone about self reported physical, psychosocial, organizational, environmental factors and the consequences of LBS (i.e. self-reported reduced activities and absenteeism). The 12-month period prevalence of reduced activities and absenteeism were 18% and 9%, respectively. Lifting (OR 1.79 95% CI 1.16-2.77) increased the risk of reduced activities. Working in awkward/tiring positions (OR 2.11 95% CI 1.20-3.70) and in a cold/damp environment (OR 2.18 95% CI 1.11-4.28) increased the risk of absenteeism. Among those with LBS, reduced activities increased with working in a hot/warm environment (OR 2.14 95% CI 1.22-3.76) and absenteeism was increased with work in awkward/tiring positions (OR 2.06 95% CI 1.13-3.77), tight deadlines (OR 1.89 95% CI 1.02-3.50), and a hot/warm environment (OR 3.35 95% CI 1.68-6.68). Interventions to reduce the consequences of LBS should aim to reduce awkward/tiring positions, lifting and work in a cold/damp environment. For individuals with LBS, additional focus should be to reduce tight deadlines, and work in hot/warm environments.

The effects of gender, long-term need for recovery and trait inhibition-rumination on morning and evening saliva cortisol secretion

Abstract The aim of this study was to investigate the long-term effects of need for recovery from work and trait rumination on saliva cortisol secretion. The sample consisted of 76 white-collar workers, 52 men and 24 women who had previously provided baseline data four years earlier and volunteered to participate in the present study. In the present study, saliva cortisol secretion was measured over seven consecutive days, on awakening, and at 10 p.m. No relationships were found between the independent variables and morning saliva cortisol levels. High trait rumination at baseline, however, was significantly related to higher evening cortisol levels for both women and men. Baseline need for recovery from work was strongly related to evening cortisol secretion for women, but in the opposite direction than expected. The present results add to the small but equivocal body of literature that has examined the long-term effects of work strain on cortisol secretion.

The Relationship Between Work‐Related Rumination and Evening and Morning Salivary Cortisol Secretion

The perseverative cognition hypothesis suggests that worry/ruminative thinking prolongs stress-related physiological activation. This study explored the association of work-related rumination with salivary cortisol sampled at 10 pm and the cortisol awakening response (CAR) the following morning. On a mid-week evening, 108 school teachers completed a small diary about their work-related thoughts and gave a saliva cortisol sample at 10 pm. The following morning, they gave four additional saliva samples: at awakening and at 15, 30 and 45 min after awakening, along with a rating of their anticipatory thoughts about work. The CAR was calculated as the percentage increase in cortisol secretion from awakening to 30 min, and the sample was divided at their respective medians to classify participants into low and high rumination groups. Cortisol secretion was found to be significantly greater in the high compared with the low ruminators at 10 pm, and this effect was not related to leisure activities or work patterns during the evening. For the morning measures, high ruminators demonstrated a flattened CAR relative to the low ruminators, and this effect appeared to be associated with sleep disturbance during the night. Ruminating about work-related issues is associated with cortisol secretion, and our findings support the perseverative cognition hypothesis.

Gender differences in work-related risk factors associated with low back symptoms.

The prevalence of low back symptoms (LBS) in many working populations is high and differences in prevalence between genders are inconsistent. However, gender-specific risk factors for LBS have seldom been examined. Hence, the aim of the present study was to indicate gender-specific LBS risk factors. A sample of 3003 people was interviewed by telephone to get information about current workplace exposure and LBS. The risk of LBS for the whole population increased with work in awkward/tiring positions (OR 1.37, 95% CI 1.12–1.68) and very/extremely stressful jobs (OR 1.46, 95% CI 1.05–2.03). None of the explanatory variables were significantly associated with LBS for males but working in awkward/tiring positions (OR 1.51, 95% CI 1.04–2.20), dissatisfaction with contact and cooperation with management (OR 1.68, 95% CI 1.02–2.78) and finding their job to be very/extremely stressful (OR 2.27, 95% CI 1.46–3.52) were significantly associated with LBS for females. Interventions to reduce LBS in workplaces should focus on reducing working in awkward/tiring positions, improving contact and cooperation with management, and reducing stressful jobs, especially amongst females. Practitioner Summary: Strategies to prevent or reduce LBS should focus on reducing exposure to awkward or tiring positions at work, improving contact and cooperation with management, and reducing stressful jobs, especially for females.