Hip pain onset in relation to cumulative workplace and leisure time mechanical load: a population based case-control study.

OBJECTIVE: In an unselected community sample of adults, to assess the role and importance of exposure to mechanical factors both at work and leisure in the aetiology of hip pain. METHOD: A population based prevalence case-control study. Cases and controls were identified from a population survey of 3847 subjects registered with two general practices in Cheshire, United Kingdom. All subjects received a postal questionnaire which inquired about hip pain during the past month. An occupational history was obtained, including exposure to each of seven physical demands. Information was also obtained on history of participation in eight common sporting activities. RESULTS: 88% of those invited to participate returned a completed questionnaire. The 352 subjects with hip pain were designated as cases, and the remaining 3002 subjects as controls. In people ever employed, hip pain was significantly associated with high cumulative workplace exposure (before onset) of walking long distances over rough ground, lifting/moving heavy weights, sitting for prolonged periods, walking long distances, frequent jumping between different levels, and standing for prolonged periods. Odds ratios (ORs) in the higher exposure categories ranged from 1.46 to 2.65. Cumulative exposure to three sporting activities was significantly associated with hip pain: track and field sports, jogging, and walking, with odds ratios varying between 1.57 to 1.94. On multivariate analysis three factors were independent predictors of hip pain onset: cumulative exposure of sitting for prolonged periods (higher exposure v not exposed: OR=1.82, 95% confidence interval (CI) 1.13 to 2.92), lifting weights >50 lb (23 kg) (OR=1.74, 95% CI 1.06 to 2.86) (both relating to the workplace), and walking as a leisure activity (OR=1.97, 95% CI 1.32 to 2.94). The population attributable risk associated with each of these activities was 21%, 13%, and 16%, respectively CONCLUSIONS: Cumulative exposure to some workplace and sporting "mechanical" risk factors for hip osteoarthritis (OA) appear to be related to hip pain in general-some (but not all) have previously been related to hip OA. Because these are common workplace or leisure time activities their attributable risk is high.

Association of occupational physical demands and psychosocial working environment with disabling shoulder pain.

OBJECTIVE: To estimate the individual and combined associations of physical and psychosocial working environment with disabling shoulder pain and to identify groups at "high risk" for shoulder pain. METHODS: A cross sectional survey was conducted at five manual occupational settings in south Manchester, United Kingdom (n=775, 83%). RESULTS: Both the duration of occupational physical demands (working postures, manual handling activities, and repetitive arm movements) and psychosocial working environment (psychological demands and lack of opportunity to learn new skills) were found to be significantly associated with shoulder pain. Three occupational factors identified a high risk group for shoulder pain: duration of lifting with one hand (prevalence rate ratio (PRR) (highest third) 2.0, 95% confidence interval (CI) 1.4 to 2.8), duration of working above shoulder level (PRR (highest third) 2.2, 95% CI 1.5 to 3.3), and whether employees found their work stressful (PRR (highest third) 1.4, 95% CI 1.0 to 2.1). In addition, a measure of psychological distress (General Health Questionnaire (GHQ) score) was found to identify a group at high risk for shoulder pain (PRR (highest third) 1.9, 95% CI 1.3 to 2.9). In employees exposed to three or more of these factors, 79% (23/29) reported shoulder pain compared with only 16% (56/353) of those not exposed to any. CONCLUSION: This study has identified a variety of occupational physical demands and psychosocial factors associated with shoulder pain. It has also identified groups of employees at a "high risk" for shoulder pain by their exposure to both physical and psychosocial factors.

Occupational risk factors for shoulder pain: a systematic review.

OBJECTIVES: To systematically evaluate the available evidence on occupational risk factors of shoulder pain. METHODS: Relevant reports were identified by a systematic search of Medline, Embase, Psychlit, Cinahl, and Current Contents. The quality of the methods of all selected publications was assessed by two independent reviewers using a standardised checklist. Details were extracted on the study population, exposures (physical load and psychosocial work environment), and results for the association between exposure variables and shoulder pain. RESULTS: 29 Studies were included in the review; three case-control studies and 26 cross sectional designs. The median method score was 60% of the maximum attainable score. Potential risk factors related to physical load and included heavy work load, awkward postures, repetitive movements, vibration, and duration of employment. Consistent findings were found for repetitive movements, vibration, and duration of employment (odds ratio (OR) 1.4-46 in studies with method scores >/= 60%). Nearly all studies that assessed psychosocial risk factors reported at least one positive association with shoulder pain, but the results were not consistent across studies for either high psychological demands, poor control at work, poor social support, or job dissatisfaction. Studies with a method score >/=60% reported ORs between 1.3 and 4.0. Substantial heterogeneity across studies for methods used for exposure assessment and data analysis impeded statistical pooling of results. CONCLUSIONS: It seems likely that shoulder pain is the result of many factors, including physical load and the psychosocial work environment. The available evidence was not consistent across studies, however, and the associations were generally not strong. Future longitudinal research should evaluate the relative importance of each individual risk factor and the role of potential confounding variables-such as exposure during leisure time-to set priorities for the prevention of shoulder pain in occupational settings.

Validity of a self-completed questionnaire measuring the physical demands of work.

OBJECTIVES: This study determined the accuracy of workers in quantifying occupational physical demands on a self-administered questionnaire. METHODS: First, a self-administered questionnaire on work postures, manual materials-handling, and repetitive upper-limb movements was validated using direct simultaneous observations for 123 randomly selected employees from 6 occupational settings. Second, weight estimation accuracy was assessed on visual analogue scales for 6 manual materials-handling activities using 20 randomly selected employees from 1 occupational setting. RESULTS: At a dichotomous level (ever-never), the accuracy of most of the self-reported physical demands was good (sensitivity 60-100%; specificity 56-100%). A more-detailed analysis of the dimensions studied (frequency, duration and amplitude) also showed that the accuracy of the self-reported estimates was satisfactory. Full agreement between the estimated and observed frequency was >60% for most of the manual materials-handling activities. In addition the average difference between the estimated and observed duration of the physical demands was found to be small. Finally the average difference between the self-reported and actual weights of various loads was found to be modest. CONCLUSIONS: The self-reported questionnaire used in this study would provide a useful instrument for estimating occupational physical demands and the frequency, duration, and amplitude of these demands in future epidemiologic studies associated with musculoskeletal pain.

Prevalence of shoulder pain in the community: the influence of case definition.

OBJECTIVE: To compare estimates of the occurrence of shoulder pain according to (a) different approaches to defining 'shoulder' and (b) restricting the definition to only include those with associated disability. METHODS: A postal questionnaire survey was sent to a sample of 500 patients registered with a general practice in south Manchester. After additional mailings to non-responders, 312 questionnaires were returned (66% adjusted response rate). Four definitions of shoulder pain were used to estimate the occurrence of symptoms derived from answers to the questionnaire. Two were based on questions asking directly about pain in the shoulder and the upper trunk and neck region respectively and two were based on markings on a pain drawing in the shoulder complex and the upper trunk respectively. To determine the occurrence of disabling shoulder pain responders were subsequently approached for interview. Of the responders, 232 (74%) were successfully interviewed. Those indicating that they were suffering from 'current' shoulder symptoms, pain on the day of interview, were asked to complete a short, 23 item, questionnaire enquiring about disability in daily living associated with such symptoms. RESULTS: In total 160 (51%) people reported shoulder pain according to at least one definition. This one month period prevalence ranged from 31% to 48% across the four definitions with the lowest estimate being for the question asking directly about shoulder symptoms. In total 84 people (27% of all respondents) answered positively to all four definitions. Only seven people who answered positively when asked directly about shoulder pain did not indicate symptoms on the pain drawing in the shoulder complex. By contrast 65 (30%) of those answering negatively to the direct question about shoulder pain indicated symptoms on the pain drawing in the upper trunk region or answered positively to the direct question about pain in the upper trunk or neck region. However only 19 (9%) of those answering negatively to the direct question indicated symptoms in the shoulder complex on the pain drawing, compared with 38 (18%) indicating symptoms in the upper trunk region and 59 (27%) symptoms in the upper trunk and neck region. Limiting the definition to only include current symptoms with some associated disability (at least one item on the disability questionnaire being answered positively) restricted the point prevalence to 20% (n = 46). CONCLUSIONS: Using a pain drawing based definition with case ascertainment restricted to an area in and around the shoulder complex is recommended for surveys assessing the occurrence of shoulder symptoms in the general population. To solve the problem of the poor specificity associated with symptom based definitions it is useful to incorporate an additional classification to restrict the definition to more disabling problems.

Occupational factors related to shoulder pain and disability.

OBJECTIVES: To determine, in a population based study, the influence of occupational factors on the occurrence of shoulder pain and disability. METHODS: A random sample of patients was selected from the register of a general practice in the Greater Manchester area of the United Kingdom. Information was collected by a posted questionnaire with specific enquiries about symptoms in the shoulder region and related disability. A lifetime occupational history was obtained including physical exposures, working conditions, and psychosocial aspects of each workplace. Analysis has been conducted as a case-control study, comparing occupational exposures at the time of onset of symptoms in those with shoulder pain and disability with corresponding occupational exposures in those without shoulder pain and disability. RESULTS: An increased risk of shoulder pain and disability in men was associated with carrying weights on one shoulder (relative risk (RR) 5.5, 95% confidence interval (95% CI) 1.8 to 17), whereas those who reported working with hands above shoulder level, using wrists or arms in a repetitive way, or stretching down to reach below knee level had about twice the risk of shoulder pain and disability. Men working frequently in very cold or damp conditions had a fourfold and sixfold risk respectively of shoulder pain and disability. Reporting of shoulder pain and disability was also more common among men and women who reported that their work caused a lot of stress (RR 1.9, 95% CI 0.9 to 4.1) or was very monotonous (RR 2.7, 95% CI 1.3 to 5.4). The relations between physical exposures, working conditions, and psychosocial factors were independent. CONCLUSIONS: This population based study has shown that physical activities carried out at work, the physical conditions under which the work is conducted, psychosocial aspects of work, or the working environment are all independently related to the occurrence of shoulder symptoms and disability, emphasising the multifactorial nature of this condition.

The frequency of restricted range of movement in individuals with self-reported shoulder pain: results from a population-based survey.

Prevalence studies suggest that shoulder pain is very common (7-20%) in the adult population, though little is known about the severity and impact of such pain. Disability results, in part, from the restriction of movement and we therefore determined the frequency of restricted shoulder movement in individuals in a general population sample reporting shoulder pain and associated disability. In all, 232 individuals were interviewed about shoulder pain and related disability, and their range of shoulder movement in the following planes was measured: elevation, forward flexion, backward flexion, external rotation and internal rotation, together with the minimum difference achieved between the tip of a thumb and the spinous process of C7. In total, 48 (21%) subjects reported current pain and disability in one or both shoulders. Using receiver operating characteristic (ROC) analysis, cut-offs for restricted movements were selected at the point of maximal discrimination between painful and pain-free shoulders. There was considerable overlap in the distribution of range of movement, at all six sites, between these two groups. The highest positive predictive value for pain was observed in restriction of the thumb to cervical spine movement (53%), but this also had the lowest negative predictive value. By contrast, the highest negative predictive value was observed for restriction of external rotation (96%). Restriction in any plane was observed in 77% of those individuals with pain, but was also present in half of those without pain. In summary, most people with self-reported shoulder pain in the community do not have widespread restriction of movement. Reduction in external rotation was the most discriminatory, but it is necessary to examine movement in multiple planes to assess the true burden of shoulder pain in the community.