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Background: Low back pain (LBP) is one of the most prevalent occupational health problems in industrialized countries. Little is known about the epidemiology of LBP in developing countries., Aims: To determine the prevalence of LBP among Nepalese textile workers and to investigate the influence of exposure to mechanical and other factors on LBP reporting., Methods: Interviewers completed questionnaires with study subjects, and work-related mechanical exposures were measured by self-completed questionnaires. Associations of LBP with mechanical factors and somatic symptoms were determined by logistic regression and reported as odds ratios (ORs) with 95% confidence intervals (CI)., Results: Nine hundred and thirty-eight workers took part, a participation rate of 92%. The 1 month period prevalence of LBP was 35% (n = 324), being higher in females than males (45% versus 28%; P < 0.001). Several work-related mechanical factors were associated with increased odds of reporting LBP: lifting heavy weights with one hand (OR 1.7; 95% CI 1.1-2.8), pushing weights (OR 1.6; 95% CI 1.2-2.3 and pulling weights (OR 1.6; 95% CI 1.1-2.1). No association was found with working posture. Strong associations were found for reporting one (OR 2.4; 95% CI 1.7-3.4) or two somatic symptoms (OR 2.7; 95% CI 1.4-5.1). On multivariable analysis, reporting of somatic symptoms (OR 2.8; 95% CI 1.5-5.4), female gender (OR 2.2; 95% CI 1.5-3.1) and increasing age were significantly associated with increased risk of reporting LBP (OR 1.7; 95% CI 1.2-2.5), but no associations were found with mechanical factors., Conclusions: This study suggests that mechanical load may not be the leading cause of LBP and adds to evidence that psychological factors play an important role in LBP in non-industrialized countries.

Objectives: To establish whether review articles provide consistent conclusions on associations between workplace psychosocial factors and musculoskeletal pain and, if differences exist, to explore whether this is related to the methods used., Methods: Reviews, reported up to February 2007, that included consideration of workplace psychosocial factors and upper limb, back or knee pain were identified through searches of multiple databases. The specific work-related psychosocial factors considered were job demands, support, job autonomy and job satisfaction. The conclusions of each review on one or more of the psychosocial/musculoskeletal pain associations were extracted., Results: 15 review articles were identified that considered one or more of the regional pain syndromes included in the study. For back pain, the most consistent conclusions (four reviews positive out of six) were with high job demands and low job satisfaction. The studies of upper limb pain were exclusively related to shoulder and/or neck pain, and the most consistent positive conclusions were with high and low job demands (four reviews positive out of six and two reviews positive out of three, respectively). For knee pain, only a single review was identified. For individual reviews of back and upper limb pain, there were marked differences in the number of associations concluded to be positive between reviews., Conclusions: The reasons for reviews coming to different conclusions included that they were often evaluating different bodies of evidence (according to their search criteria, the year when the review was conducted, the role that quality assessment played in whether studies contributed to evidence, and the combination of risk factors addressed in individual studies), but more important was whether the review specified explicit criteria for making conclusions on strength of evidence. These conclusions emphasise the importance of developing standardised methods for conducting such evaluations of existing evidence and the importance of new longitudinal studies for clarifying the temporal relationship between psychosocial factors and musculoskeletal pain in the workplace.

Background: We have recently demonstrated that individual psychosocial factors are important predictors of the onset of chronic widespread pain. It has been hypothesized that excessive mechanical exposure may also be associated with symptom onset, although this has not been formally examined. We therefore determined the relative contributions of individual psychosocial and work-related mechanical, posture and environment factors in symptom onset., Methods: We conducted a population-based prospective survey and identified 1658 adults aged 18-65 yr who were symptom-free. At baseline, detailed information was obtained on work-related mechanical and environment factors using validated instruments. Individual psychosocial features were also measured. Subjects free of chronic widespread pain at baseline were followed up at 12 and 36 months to identify those reporting the onset of new symptoms., Results: In all, 1445 (91%) returned the questionnaire at 12 months and 978 (89%) at 36 months. Of these, 81 and 92 respectively reported new chronic widespread pain. Symptom onset was predicted by workplace factors [pushing/pulling heavy weights [relative risk (RR) = 1.8, 95% confidence interval (CI) 1.1, 3.0]; repetitive movements of the wrists (RR = 1.8, 95% CI 1.2, 2.7); kneeling (RR = 2.2, 95% CI 1.2, 4.1)] and individual factors [aspects of illness behaviour (RR = 2.9, 95% CI 1.6, 5.3); somatic symptoms (RR = 1.9 95% CI 1.1, 3.3); fatigue (RR = 1.9, 95% CI 1.2, 3.1); baseline pain symptoms (RR = 2.5, 95% CI 1.6, 3.9)]. In multivariate analysis, pushing/pulling heavy weights, repetitive wrist movements, kneeling and other pain at baseline were associated with new-onset chronic widespread pain. However, the strongest predictor was a high score on the illness behaviour scale., Conclusion: This study provides only limited support for the hypothesis that low-level mechanical injury may be a risk factor for developing chronic widespread pain. The onset of chronic widespread pain appears to be multifactorial and is strongly predicted by individual psychosocial factors.

Aim: To test the hypothesis that work related mechanical and psychosocial factors predict new onset shoulder pain in newly employed workers., Methods: Two year prospective study of newly employed workers from 12 diverse occupational settings. At baseline, 1081 subjects provided information on work related mechanical and psychosocial risk factors, and current pain status., Results: In all, 803 (74%) subjects were free from shoulder pain at baseline. Of those, 638 (79%) responded at 12 months and 476 (88%) at 24 months. New onset shoulder pain was reported by 93 (15%) and 73 (15%) subjects respectively. An increased risk of symptom onset was found in subjects reporting mechanical exposures involving heavy weights including lifting with one or two hands, carrying on one shoulder, lifting at or above shoulder level, and pushing or pulling. Working with hands above shoulder level was also predictive of new onset shoulder pain. Of the psychosocial factors examined, the strongest predictor was monotonous work. Those individuals with any other previous pain also had an increased risk of new onset shoulder pain at follow up. In multivariate analysis, lifting heavy weights with one or two hands, pushing or pulling heavy weights, working with hands above shoulder level, and monotonous work were independently associated with new onset shoulder pain., Conclusions: This study supports the hypothesised relation between mechanical risk factors and shoulder pain. In general, work related psychosocial factors were modestly associated with new onset shoulder pain. However, monotonous work was a strong risk factor for new onset shoulder pain.

Objectives: To test the hypothesis that work-related mechanical, psychosocial and physical environment factors would predict new-onset low back pain (LBP) in newly employed workers., Methods: A total of 1186 newly employed workers were recruited from a variety of occupational settings. Those who were free from LBP at baseline were identified. Subjects were followed up at 12 and 24 months. Work-related mechanical, psychosocial and physical environment exposures were measured. Generalized estimating equations were used to assess predictors of new-onset LBP., Results: New-onset LBP was reported by 119 (19%) and 81 (19%) subjects at 12 and 24 months, respectively. Several work-related mechanical exposures predicted new-onset LBP including lifting heavy weights with one or two hands, lifting heavy weights at or above shoulder level, pulling heavy weights, kneeling or squatting for 15 min or longer. Of the psychosocial factors examined, stressful and monotonous work significantly predicted symptom onset. In addition, hot working conditions and pain at other sites also predicted new-onset LBP. On multivariate analysis these risks were only moderately attenuated but the 95% confidence intervals excluded unity only for the latter, non-mechanical, exposures., Conclusion: In this cohort of newly employed workers, from a range of occupations, several aspects of the work-place environment, other than mechanical factors, were important in predicting new-onset LBP. These results emphasize that interventions aimed at reducing the occurrence of LBP are likely to be most successful if they intervene across these domains.

Objective: To determine whether adverse psychosocial and individual psychological factors increase the risk of pain across regional sites., Methods: A prospective study was conducted of newly employed workers from 12 diverse occupational groups. Near to the beginning of subjects' employment, details of work related psychosocial factors and individual psychological distress were obtained by means of a self completed questionnaire. Questionnaire follow up after 12 months provided data on these same exposures and ascertained pain at any of four anatomical sites: the low back, shoulder, wrist/forearm, and knee., Results: Of the original 1081 subjects, 829 (77%) provided full details at the one year follow up. Psychosocial work demands and high levels of individual psychological distress were found to have a common effect across sites. Psychological distress was associated with a doubling of the risk of reported pain (odds ratio = 2.1, 95% confidence interval 1.6 to 2.7), while aspects of job demand, poor support from colleagues, and work dissatisfaction were all associated with increased odds of reported pain onset of between 1.4 and 1.7. These effects were almost all common across the four regional pain sites., Conclusions: In cohorts of newly employed workers, certain work related psychosocial factors and individual psychological distress are associated with the subsequent reporting of musculoskeletal pain, and generally this effect is common across anatomical sites.

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.

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.

Objective: To determine the influence of short term work related psychosocial factors (work demands, job control, and social support) and psychological distress on regional pain syndromes., Methods: Newly employed workers were recruited from 12 occupational groups and information collected by questionnaire. Subjects indicated on a blank body manikin any low back, shoulder, wrist/forearm, or knee pain that had occurred during the past month and lasted more than one day. Data were also collected on work related psychosocial factors and on levels of psychological distress [using the General Health Questionnaire (GHQ)]. The relationships between psychosocial factors and psychological distress and each area of pain were calculated as odds ratios with 95% confidence intervals. Adjustment was made for age, sex, and occupational group., Results: 1081 subjects (median age 23; interquartile range 20-27) were recruited to the study shortly after commencing employment: 261 (24%) reported low back pain, 221 (20%) reported shoulder pain, 93 (9%) reported wrist/forearm pain, and 222 (21%) reported knee pain. High levels of psychological distress were associated with increased likelihood of pain, with a trend observed between scores on the GHQ and the odds of pain in each of the 4 sites. Those who perceived their work as stressful most of the time were more likely to report back (OR 1.8, 95% CI 1.01-3.1) or shoulder pain (OR 1.9, 95% CI 1.02-3.4) than those who considered their work seldom stressful. Pace of work or job autonomy was less markedly related to pain at individual sites. Strong relationships were observed between psychological distress, job demands (stressful work, hectic work), low job control, and pain at multiple sites., Conclusion: The study has shown that adverse work related psychosocial factors, in particular aspects of job demand and control, influence the reporting of regional musculoskeletal pain. This occurs even after only short term exposure. The odds of reporting these adverse exposures are increased when pain is reported at multiple sites.

Objectives: To determine the influence of short term exposure to mechanical factors on regional musculoskeletal pain., Methods: Full time newly employed workers were recruited from 12 occupational groups and information collected by questionnaire. Subjects indicated on a blank body manikin any low back, shoulder, wrist or forearm or both, or knee pain which had occurred during the past month and had lasted more than 1 day. Data were also collected with a previously validated questionnaire on working postures, manual handling activities, and repetitive movements of the upper limb. The relations between mechanical factors and each area of pain were calculated as odds ratios (ORs) with 95% confidence intervals (95% CIs). Adjustment was made for age and sex., Results: 1081 subjects (median age 23; interquartile range 20--27) were recruited to the study (a participation rate of 91%). 261 (24%) reported low back pain, 221 (20%) shoulder pain, 93 (9%) wrist or forearm pain, and 222 (21%) knee pain. Several specific manual handling activities were found to be associated with low back, shoulder, and knee pain. Carrying weights of more than 50 lbs (23 kg) on one shoulder was the factor which was most strongly associated with low back pain (OR 2.4 (95% CI 1.5 to 3.8)), shoulder pain (OR 3.1 (95% CI 1.9 to 4.8)), and knee pain (OR 3.5 (95% CI 2.2 to 5.5)), whereas forearm pain was most strongly associated with repetitive movements of the wrists (OR 1.8 (95% CI 1.04 to 3.1)). By contrast very few postures were associated with regional pain, although bending forwards in an uncomfortable position for at least 15 minutes was associated with shoulder pain (OR 1.6 (95% CI 1.2 to 2.2)) and kneeling for at least 15 minutes was associated with knee pain (OR 1.8 (95% CI 1.2 to 2.6)). Exposure to mechanical factors was most strongly associated with pain at multiple sites rather than with pains in individual regions., Conclusions: Even among workers with only short term exposure to mechanical factors, musculoskeletal pain is increased.

Objective: To determine the aetiology of forearm pain. In particular to determine the relative contribution of (a) psychological factors, features of somatisation, and health anxiety and behaviour, (b) work related mechanical factors, and (c) work related psychosocial factors in the onset of forearm pain., Design: 2 year prospective population based cohort study, with retrospective assessment of exposures at work., Setting: Altrincham, Greater Manchester., Participants: 1953 individuals aged 18-65 years., Outcome Measures: Forearm pain of new onset., Results: At follow up, 105 (8.3%) participants reported forearm pain of new onset lasting at least one day in the past month. Among these, 67% also reported shoulder pain, 65% back pain, and 45% chronic widespread pain. Increased risks of onset were associated with high levels of psychological distress (relative risk 2.4, 95% confidence interval 1.5 to 3.8), reporting at least two other somatic symptoms (1.7, 0.95 to 3.0), and high scores on the illness behaviour subscale of the illness attitude scales. The two work related mechanical exposures associated with the highest risk of forearm pain in the future were repetitive movements of the arm (4.1, 1.7 to 10) or wrists (3.4, 1.3 to 8.7), whereas the strongest work related psychosocial risk was dissatisfaction with support from colleagues or supervisors (4.7, 2. 2 to 10)., Conclusions: Psychological distress, aspects of illness behaviour, and other somatic symptoms are important predictors of onset of forearm pain in addition to work related psychosocial and mechanical factors. Misleading terms such as "cumulative trauma disorder" or "repetitive strain injury," implying a single uniform aetiology, should be avoided.

Objectives: To examine whether psychosocial risks for low back pain, reported in previous studies, are specific to the working population or are more widely relevant., Methods: A large population-based survey identified subjects free of low back pain, and obtained information on the degree of satisfaction with work (or not working) and the adequacy of income for their family's needs. New episodes of consulting and non-consulting low back pain were identified prospectively over 12 months. The psychosocial risks for developing a new low back pain episode are examined in employed and non-employed groups separately., Results: Dissatisfaction with work status doubled the risk of reporting a new low back pain episode in both the employed (odds ratio 2.0, 95% confidence intervals 1.2, 3.3) and non-employed (OR 2.0, 1.2, 3.1). Those perceiving their income as inadequate were at a threefold risk of consulting for this symptom regardless of their employment status (employed: OR 3.6, 1.8, 7.2; non-employed: OR 3.6, 1.4, 9.0)., Conclusion: Psychosocial factors pose similar risks for a new low back pain episode in workers and the non-employed. This suggests that such influences may not be related solely to work but be a function of general aspects of life. The economic and individual impact of psychosocial interventions in the workplace, therefore, are likely to be limited unless account is taken of the influence of broader non-work related aspects.

Study Design: A prospective, population-based cohort study of working adults., Objectives: To determine whether work-related psychosocial factors and social status predict the occurrence of new episodes of low back pain and influence consultation behavior., Summary and Background Data: Dissatisfaction with work and social status has been associated with low back pain in several studies; few of these studies have been prospective or population based., Methods: An initial postal survey was returned by 4,501 (59%) adults (18-75 years old) registered with two primary care practices. From this, a cohort of 1,412 people currently in employment and free of low back pain was identified, and baseline information on work-related psychosocial factors and psychologic distress was obtained. Social class was derived from current occupation using a standardized classification. New episodes of low back pain occurring in the next 12 months were identified by continuous monitoring of primary care consulters and by mailing a second questionnaire a year later to identify occurrences of low back pain for which no consultation was sought., Results: The baseline cross-sectional survey showed modest but significant associations between low back pain and perceived inadequacy of income (risk ratio 1.3), dissatisfaction with work (risk ratio 1.4) and social class IV/V (risk ratio 1.2). In the follow-up year, the risk of reporting low back pain for which no consultation was sought doubled in those dissatisfied with their work. Both perceived inadequacy of income (odds ratio 3.6) and social class IV/V (odds ratio 4.8) were strongly associated with consulting with a new episode of low back pain during the follow-up year, an association more marked in women. The associations with work dissatisfaction and perceived adequacy of income were not explained by general psychologic distress or social status., Conclusion: People dissatisfied with work are more likely to report low back pain for which they do not consult a physician, whereas lower social status and perceived inadequacy of income are independent risks for working people to seek consultation because of low back pain.

Study Design: A population-based longitudinal study conducted in northwest England for a 12-month period involving adults aged 18-75 years., Objectives: To determine physical factors related to employment that predict a new episode of low back pain., Summary of Background Data: Most epidemiologic studies that have examined the relation between occupation and back pain have been cross-sectional or retrospective in design. Because workers who have experienced low back pain may have changed jobs or work activities, it is important to use longitudinal studies that define "exposures" before the onset of symptoms., Methods: From adults registered with two general practices in northwest England, 1412 people who were currently in employment and free of low back pain were identified. A lifetime occupational history was recorded for all participants, with details of activities performed in each occupation. Data on consultations for low back pain during the follow-up year were collected through computerized medical records, whereas those who had not consulted with low back pain were sent another questionnaire at the end of the 1-year follow-up., Results: An increased risk of a new episode of low back pain was found in those whose jobs involved lifting/pulling/pushing objects of at least 25 lbs, or whose jobs involved prolonged periods of standing or walking. Risks were, in general, greater in women, for a first ever episode of back pain and for back pain that led to a general practice consultation. No clear relation between years of exposure to such factors and magnitude of risk was evident., Conclusions: Occupational activities, particularly in women, such as working with heavy weights or lengthy periods of standing or walking, were associated with the occurrence of low back pain. Short-term influences may be more important in the occurrence of new episodes rather than cumulative lifetime exposure, and emphasize that such morbidity may be avoidable.

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.