To quantify the variation in rates of absence for musculoskeletal pain across 47 occupational groups (mostly nurses and office workers) from 18 countries, and to explore personal and group-level risk factors that might explain observed differences.
A standardised questionnaire was used to obtain information about musculoskeletal pain, sickness absence and possible risk factors in a cross-sectional survey of 12,416 workers (92 to 1017 per occupational group). In addition, group-level data on socioeconomic variables such as sick pay and unemployment rates were assembled by members of the study team in each country. Associations of sickness absence with risk factors were examined by Poisson regression.
Overall, there were more than 30-fold differences between occupational groups in the 12-month prevalence of prolonged musculoskeletal sickness absence, and even among office workers carrying out similar occupational tasks, the variation was more than ten-fold. Personal risk factors included older age, lower educational level, tendency to somatise, physical loading at work and prolonged absence for non-musculoskeletal illness. However, these explained little of the variation between occupational groups. After adjustment for individual characteristics, prolonged musculoskeletal sickness absence was more frequent in groups with greater time pressure at work, lower job control, and more adverse beliefs about the work-relatedness of musculoskeletal disorders.
Musculoskeletal sickness absence might be reduced by eliminating excessive time pressures in work, maximising employees’ responsibility and control, and providing flexibility of duties for those with disabling symptoms. Care should be taken not to overstate work as a cause of musculoskeletal injury.
Sickness absence; musculoskeletal; international; risk factors; time pressure; job control
It is unclear whether and to what extent intensive case management is more effective than standard occupational health services in reducing sickness absence in the healthcare sector.
To evaluate a new return to work service at an English hospital trust.
The new service entailed intensive case management for staff who had been absent sick for longer than four weeks, aiming to restore function through a goal-directed and enabling approach based on a bio-psycho-social model. Assessment of the intervention was by controlled before and after comparison with a neighbouring hospital trust at which there were no major changes in the management of sickness absence. Data on outcome measures were abstracted from electronic databases held by the two trusts.
At the intervention trust, the proportion of 4-week absences which continued beyond 8 weeks fell from 51.7% in 2008 to 49.1% in 2009 and 45.9% in 2010. The reduction from 2008 to 2010 contrasted with an increase at the control trust from 51.2% to 56.1% – a difference in change of 10.7% (95%CI 1.5% to 20.0%). There was also a differential improvement in mean days of absence beyond four weeks, but this was not statistically significant (1.6 days per absence, 95%CI −7.2 to 10.3 days).
Our findings suggest that the intervention was effective, and calculations based on an annual running cost of £57,000 suggest that it was also cost-effective. A similar intervention should now be evaluated at a larger number of hospital trusts.
Sickness absence; case management; intervention; evaluation; cost-effectiveness; healthcare
To explore definitions for multi-site pain, and compare associations with risk factors for different patterns of musculoskeletal pain, we analysed cross-sectional data from the Cultural and Psychosocial Influences on Disability (CUPID) study. The study sample comprised 12,410 adults aged 20-59 years from 47 occupational groups in 18 countries. A standardised questionnaire was used to collect information about pain in the past month at each of 10 anatomical sites, and about potential risk factors. Associations with pain outcomes were assessed by Poisson regression, and characterised by prevalence rate ratios (PRRs). Extensive pain, affecting 6-10 anatomical sites, was reported much more frequently than would be expected if the occurrence of pain at each site were independent (674 participants v 41.9 expected). In comparison with pain involving only 1-3 sites, it showed much stronger associations (relative to no pain) with risk factors such as female sex (PRR 1.6 v 1.1), older age (PRR 2.6 v 1.1), somatising tendency (PRR 4.6 v 1.3) and exposure to multiple physically stressing occupational activities (PRR 5.0 v 1.4). After adjustment for number of sites with pain, these risk factors showed no additional association with a distribution of pain that was widespread according to the frequently used American College of Rheumatology (ACR) criteria. Our analysis supports the classification of pain at multiple anatomical sites simply by the number of sites affected, and suggests that extensive pain differs importantly in its associations with risk factors from pain that is limited to only a small number of anatomical sites.
In a large cross-sectional survey, pain affecting 6–10 anatomical sites showed substantially different associations with risk factors from pain limited to 1–3 sites.
To explore definitions for multisite pain, and compare associations with risk factors for different patterns of musculoskeletal pain, we analysed cross-sectional data from the Cultural and Psychosocial Influences on Disability (CUPID) study. The study sample comprised 12,410 adults aged 20–59 years from 47 occupational groups in 18 countries. A standardised questionnaire was used to collect information about pain in the past month at each of 10 anatomical sites, and about potential risk factors. Associations with pain outcomes were assessed by Poisson regression, and characterised by prevalence rate ratios (PRRs). Extensive pain, affecting 6–10 anatomical sites, was reported much more frequently than would be expected if the occurrence of pain at each site were independent (674 participants vs 41.9 expected). In comparison with pain involving only 1–3 sites, it showed much stronger associations (relative to no pain) with risk factors such as female sex (PRR 1.6 vs 1.1), older age (PRR 2.6 vs 1.1), somatising tendency (PRR 4.6 vs 1.3), and exposure to multiple physically stressing occupational activities (PRR 5.0 vs 1.4). After adjustment for number of sites with pain, these risk factors showed no additional association with a distribution of pain that was widespread according to the frequently used American College of Rheumatology criteria. Our analysis supports the classification of pain at multiple anatomical sites simply by the number of sites affected, and suggests that extensive pain differs importantly in its associations with risk factors from pain that is limited to only a small number of anatomical sites.
Pain; Multisite; Widespread; Definition; Risk factors
To explore whether risk factors for neurophysiologically confirmed carpal tunnel syndrome (CTS) differ from those for sensory symptoms with normal median nerve conduction, and to test the validity and practical utility of a proposed definition for impaired median nerve conduction, we carried out a case–control study of patients referred for investigation of suspected CTS.
We compared 475 patients with neurophysiological abnormality (NP+ve) according to the definition, 409 patients investigated for CTS but classed as negative on neurophysiological testing (NP-ve), and 799 controls. Exposures to risk factors were ascertained by self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression.
NP+ve disease was associated with obesity, use of vibratory tools, repetitive movement of the wrist or fingers, poor mental health and workplace psychosocial stressors. NP-ve illness was also related to poor mental health and occupational psychosocial stressors, but differed from NP+ve disease in showing associations also with prolonged use of computer keyboards and tendency to somatise, and no relation to obesity. In direct comparison of NP+ve and NP-ve patients (the latter being taken as the reference category), the most notable differences were for obesity (OR 2.7, 95 % CI 1.9-3.9), somatising tendency (OR 0.6, 95% CI 0.4-0.9), diabetes (OR 1.6, 95% CI 0.9-3.1) and work with vibratory tools (OR 1.4, 95% CI 0.9-2.2).
When viewed in the context of earlier research, our findings suggest that obesity, diabetes, use of hand-held vibratory tools, and repeated forceful movements of the wrist and hand are causes of impaired median nerve function. In addition, sensory symptoms in the hand, whether from identifiable pathology or non-specific in origin, may be rendered more prominent and distressing by hand activity, low mood, tendency to somatise, and psychosocial stressors at work. These differences in associations with risk factors support the validity of our definition of impaired median nerve conduction.
Carpal tunnel syndrome; Nerve conduction; Case–control; Obesity; Vibration; Occupation; Psychosocial; Somatising tendency; Upper limb disorders
We have previously proposed that sensory nerve conduction (SNC) in the median nerve should be classed as abnormal when the difference between conduction velocities in the little and index fingers is > 8 m/s. In a prospective longitudinal study, we investigated whether this case definition distinguished patients who were more likely to benefit from surgical treatment.
We followed up 394 patients (response rate 56%), who were investigated by a neurophysiology service for suspected carpal tunnel syndrome. Information about symptoms, treatment and other possible determinants of outcome was obtained through questionnaires at baseline and after follow-up for a mean of 19.2 months. Analysis focused on 656 hands with numbness, tingling or pain at baseline. Associations of surgical treatment with resolution of symptoms were assessed by Poisson regression, and summarised by prevalence rate ratios (PRRs) and associated 95% confidence intervals (95% CIs).
During follow-up, 154 hands (23%) were treated surgically, and sensory symptoms resolved in 241 hands (37%). In hands with abnormal median SNC, surgery was associated with resolution of numbness, tingling and pain (PRR 1.5, 95% CI 1.0-2.2), and of numbness and tingling specifically (PRR 1.8, 95% CI 1.3-2.6). In contrast, no association was apparent for either outcome when median SNC was classed as normal.
Our definition of abnormal median SNC distinguished a subset of patients who appeared to benefit from surgical treatment. This predictive capacity gives further support to its validity as a diagnostic criterion in epidemiological research.
Carpal tunnel syndrome; Neurophysiology; Case definition; Validity; Surgery; Outcome
To inform the clinical management of patients with suspected carpal tunnel syndrome (CTS) and case definition for CTS in epidemiological research, we explored the relation of symptoms and signs to sensory nerve conduction (SNC) measurements.
Patients aged 20–64 years who were referred to a neurophysiology service for investigation of suspected CTS, completed a symptom questionnaire (including hand diagrams) and physical examination (including Tinel’s and Phalen’s tests). Differences in SNC velocity between the little and index finger were compared according to the anatomical distribution of symptoms in the hand and findings on physical examination.
Analysis was based on 1806 hands in 908 patients (response rate 73%). In hands with numbness or tingling but negative on both Tinel’s and Phalen’s tests, the mean difference in SNC velocities was no higher than in hands with no numbness or tingling. The largest differences in SNC velocities occurred in hands with extensive numbness or tingling in the median nerve sensory distribution and both Tinel’s and Phalen’s tests positive (mean 13.8, 95% confidence interval (CI) 12.6-15.0 m/s). Hand pain and thumb weakness were unrelated to SNC velocity.
Our findings suggest that in the absence of other objective evidence of median nerve dysfunction, there is little value in referring patients of working age with suspected CTS for nerve conduction studies if they are negative on both Tinel’s and Phalen’s tests. Alternative case definitions for CTS in epidemiological research are proposed according to the extent of diagnostic information available and the relative importance of sensitivity and specificity.
Epidemiology; Evidence-based medicine; Hand; Nerve compression syndromes; Wrist
The paper describes the adaptation and testing of the Cultural and Psychosocial Influences on Disability Questionnaire for use in Portuguese. The cross-cultural adaptation followed the steps of translation, back-translation, evaluation of the translations by a committee of judges, and then piloting of the pre-final version. This was performed in a sample of 40 nursing staff from the Hospital at the University of São Paulo. Adjustments were made after review of the translations by the committee of judges (CVI≤ 80%). The pilot study was used to test whether questions could be satisfactorily understood and completed (≥ 85% of subjects). The Brazilian version of the Questionnaire is an adequate instrument for the ascertainment of occupational activities, psychosocial aspects of work, musculoskeletal symptoms and associated disabilities in nursing staff.
Translations; Validation Studies; Occupational Health; Cumulative Trauma Disorders
Knee osteoarthritis (kOA) risk is increased by obesity and physical activities (PA) which mechanically stress the joint. We examined the associations of midlife kOA with body mass index (BMI) and activity exposure across adult life and their interaction.
Data are from a UK birth cohort of 2597 participants with a clinical assessment for kOA at age 53. At ages 36, 43 and 53 BMI (kg/m2), self-reported leisure-time PA, and occupational activity (kneeling/squatting; lifting; climbing; sitting; assigned using a job-exposure matrix) were ascertained. Associations were explored using the multiplicative logistic model.
BMI was strongly and positively associated with kOA in men and women. Men and women in manual occupations also had greater odds of kOA; there was a weak suggestion that kOA risk was higher among men exposed to lifting or kneeling at work. For men, the only evidence of a multiplicative interaction between BMI and activities was for lifting (p = 0.01) at age 43; BMI conferred higher kOA risk among those most-likely to lift at work (OR per increase in BMI z-score: 3.55, 95% CI: 1.72-7.33). For women, the only evidence of an interaction was between BMI and leisure-time PA (p = 0.005) at age 43; BMI conferred higher kOA risk among those at higher PA levels (OR per increase in BMI z-score: 1.59, 95% CI: 1.26-2.00 in inactive; 1.70, 95% CI: 1.14-2.55 (less-active); and 4.44; 95% CI: 2.26-8.36 (most-active).
At the very least, our study suggests that more active individuals (at work and in leisure) may see a greater reduction in risk of kOA from avoiding a high BMI than those less active.
Knee osteoarthritis; Body mass index; Physical activity; Occupational activity
To explore occupational and psychological risk factors for the incidence and persistence of multi-site musculoskeletal pain.
We conducted a longitudinal investigation of three occupational groups in Crete, Greece. Baseline information was obtained at interview about pain in the past year at each of six anatomical sites, and about possible risk factors for subsequent symptoms. Twelve months later, subjects were re-interviewed about pain at the same anatomical sites in the past month. Pain at two or more sites was classed as multi-site. Associations with new development and persistence of multi-site pain at follow-up were assessed by logistic regression.
Analysis was based on 518 subjects (87% of those originally selected for study). At follow-up, multi-site pain persisted in 217 (62%) of those who had experienced it in the year before baseline, and was newly developed in 27 (17%) of those who had not. Persistence of multi-site pain was significantly related to physical loading at work, somatising tendency and beliefs about work as a cause of musculoskeletal pain, with ORs (95%CIs) for the highest relative to the lowest exposure categories of 2.3 (1.0-5.6), 2.6 (1.5-4.6) and 1.9 (1.1-3.3) respectively. Development of new multi-site pain was most strongly associated with working for ≥ 40 hours per week (OR 5.0, 95%CI 1.1-24.0).
Our findings confirm the importance of both physical loading at work and somatising tendency as risk factors for multi-site pain, and suggest that persistence of pain is also influenced by adverse beliefs about work-causation.
To assess the importance of psychological and culturally-influenced factors as predictors of incidence and persistence of LBP in a Spanish working population.
As part of the international CUPID study, 1105 Spanish nurses and office workers, aged 20-59 years, answered questions at baseline about LBP in the past month and past year, associated disability, occupational lifting, smoking habits, health beliefs, mental health, and distress from common somatic symptoms. At follow-up 12 months later, they were asked again about LBP and associated disability in the past month. Associations with the incidence and persistence of LBP were assessed by log binomial regression, and characterised by prevalence rate ratios (PRRs) with associated 95% confidence intervals (CIs).
971 participants (87.9%) completed follow-up. Among 579 with no LBP at baseline, 22.8% reported LBP at follow-up. After adjustment for sex, age and occupation, development of new LBP was predicted by poor mental health (PRR 1.5, 95%CI 1.0-2.2), somatising tendency (PRR 1.8, 95%CI 1.2-2.7), and presence of LBP for >1 month in the year before baseline (PRR 4.7, 95%CI 3.1-6.9). Among 392 subjects who had LBP at baseline, 59.4% reported persistence at follow-up. Persistence of LBP was associated with presence of symptoms for >1 month in the 12 months before baseline (PRR 1.4, 95%CI 1.2-1.7), and more weakly with somatising tendency, and with adverse beliefs about the work-relatedness and prognosis of LBP
In Spain, as in northern European countries, psychological and culturally-influenced factors have an important role in the development and persistence of LBP.
low back pain; health beliefs; mental health; somatising tendency
Statistics from Labour Force Surveys are widely quoted as evidence for the scale of occupational illness in Europe. However, occupational attribution depends on whether participants believe their health problem is caused or aggravated by work, and personal beliefs may be unreliable. We assessed the potential for error for work-associated arm pain.
We mailed a questionnaire to working-aged adults, randomly chosen from five British general practices. We asked about: occupational activities; mental health; self-rated health; arm pain; and beliefs about its causation. Those in work (n = 1769) were asked about activities likely to cause arm pain, from which we derived a variable for exposure to any ‘arm-straining’ occupational activity. We estimated the relative risk (RR) from arm-straining activity, using a modified Cox model, and derived the population attributable fraction (PAF). We compared the proportion of arm pain cases reporting their symptom as caused or made worse by work with the calculated PAF, overall and for subsets defined by demographic and other characteristics.
Arm pain in the past year was more common in the 1,143 subjects who reported exposure to arm-straining occupational activity (RR 1.2, 95% confidence interval 1.1 to 1.5). In the study sample as a whole, 53.9% of 817 cases reported their arm pain as work-associated, whereas the PAF for arm-straining occupational activity was only 13.9%. The ratio of cases reported as work-related to the calculated attributable number was substantially higher below 50 years (5.4) than at older ages (3.0) and higher in those with worse self-rated and mental health.
Counting people with arm pain which they believe to be work-related can overestimate the number of cases attributable to work substantially. This casts doubt on the validity of a major source of information used by European Governments to evaluate their occupational health strategies.
Large international variation in the prevalence of disabling forearm and low back pain was only partially explained by established personal and socioeconomic risk factors.
To compare the prevalence of disabling low back pain (DLBP) and disabling wrist/hand pain (DWHP) among groups of workers carrying out similar physical activities in different cultural environments, and to explore explanations for observed differences, we conducted a cross-sectional survey in 18 countries. Standardised questionnaires were used to ascertain pain that interfered with everyday activities and exposure to possible risk factors in 12,426 participants from 47 occupational groups (mostly nurses and office workers). Associations with risk factors were assessed by Poisson regression. The 1-month prevalence of DLBP in nurses varied from 9.6% to 42.6%, and that of DWHP in office workers from 2.2% to 31.6%. Rates of disabling pain at the 2 anatomical sites covaried (r = 0.76), but DLBP tended to be relatively more common in nurses and DWHP in office workers. Established risk factors such as occupational physical activities, psychosocial aspects of work, and tendency to somatise were confirmed, and associations were found also with adverse health beliefs and group awareness of people outside work with musculoskeletal pain. However, after allowance for these risk factors, an up-to 8-fold difference in prevalence remained. Systems of compensation for work-related illness and financial support for health-related incapacity for work appeared to have little influence on the occurrence of symptoms. Our findings indicate large international variation in the prevalence of disabling forearm and back pain among occupational groups carrying out similar tasks, which is only partially explained by the personal and socioeconomic risk factors that were analysed.
Low back; Forearm; Pain; International; Socioeconomic; Psychosocial
The aim of this study was to investigate whether whole-body vibration (WBV) is associated with prolapsed lumbar intervertebral disc (PID) and nerve root entrapment among patients with low-back pain (LBP) undergoing magnetic resonance imaging (MRI).
A consecutive series of patients referred for lumbar MRI because of LBP were compared with controls X-rayed for other reasons. Subjects were questioned about occupational activities loading the spine, psychosocial factors, driving, personal characteristics, mental health, and certain beliefs about LBP. Exposure to WBV was assessed by six measures, including weekly duration of professional driving, hours driven at a spell, and current 8-hour daily equivalent root-mean-square acceleration A(8). Cases were sub-classified according to whether or not PID/nerve root entrapment was present. Associations with WBV were examined separately for cases with and without these MRI findings, with adjustment for age, sex, and other potential confounders.
Altogether, 237 cases and 820 controls were studied, including 183 professional drivers and 176 cases with PID and/or nerve root entrapment. Risks associated with WBV tended to be lower for LBP with PID/nerve root entrapment but somewhat higher for risks of LBP without these abnormalities. However, associations with the six metrics of exposure were all weak and not statistically significant. Neither exposure–response relationships nor increased risk of PID/nerve root entrapment from professional driving or exposure at an A(8) above the European Union daily exposure action level were found.
WBV may be a cause of LBP but it was not associated with PID or nerve root entrapment in this study.
back pain; disc pathology; whole-body vibration
Analysis of occupational mortality in England and Wales during 1991-2000 showed no decline in work-attributable deaths from asbestosis.
To explore why there was no decline in mortality from asbestosis despite stricter controls on asbestos exposure over recent decades.
Using data from registers of all deaths in Great Britain with mention of mesothelioma or asbestosis on the death certificate, we plotted death rates by five-year age group within five-year birth cohorts for a) mesothelioma and b) asbestosis without mention of mesothelioma.
Analysis was based on a total of 33,751 deaths from mesothelioma and 5,396 deaths from asbestosis. For both diseases, mortality showed a clear cohort effect; and within birth cohorts, death rates increased progressively with age through to 85 years and older. However, highest mortality from mesothelioma was in men born during 1939-43, whereas mortality from asbestosis peaked in men born during 1924-38.
Our findings suggest that in Britain, mortality from asbestosis has been determined mainly by cumulative exposure to asbestos before 45 years of age, and that the effect of such exposure continues through to old age. That mortality from asbestosis peaked in earlier birth cohorts than mortality from mesothelioma may reflect a difference in exposure-response relationships for the two diseases. The discrepancy could be explained if risk of asbestosis increased more steeply than that of mesothelioma at higher levels of exposure to asbestos, and if the highest prevalence of heavy exposure occurred in earlier birth cohorts than the highest prevalence of less intense exposures.
Asbestos; asbestosis; mesothelioma; trends; cohort effect
As part of the international CUPID investigation, we compared physical and psychosocial risk factors for musculoskeletal disorders among nurses in Brazil and Italy. Using questionnaires, we collected information on musculoskeletal disorders and potential risk factors from 751 nurses employed in public hospitals. By fitting country specific multiple logistic regression models, we investigated the association of stressful physical activities and psychosocial characteristics with site-specific and multisite pain, and associated sickness absence. We found no clear relationship between low back pain and occupational lifting, but neck and shoulder pain were more common among nurses who reported prolonged work with the arms in an elevated position. After adjustment for potential confounding variables, pain in the low back, neck and shoulder, multisite pain, and sickness absence were all associated with somatizing tendency in both countries. Our findings support a role of somatizing tendency in predisposing to musculoskeletal disorders, acting as an important mediator of the individual response to triggering exposures, such as workload.
Nursing Staff; Cross-cultural Comparison; Musculoskeletal Diseases; Absenteeism
Pain in the neck and shoulder has been linked with various psychosocial risk factors, as well as with occupational physical activities. However, most studies to date have been cross-sectional, making it difficult to exclude reverse causation. Moreover, they have been carried out largely in northern Europe, and the relationship to psychosocial factors might be different in other cultural environments.
To explore causes of neck/shoulder pain, we carried out a longitudinal study in Iranian nurses and office workers. Participants (n = 383) completed a baseline questionnaire about neck/shoulder pain in the past month and possible risk factors, and were again asked about pain 12 months later. Associations with pain at follow-up were explored by Poisson regression and summarised by prevalence rate ratios (PRRs).
After adjustment for other risk factors, new pain at follow-up was more frequent in office workers than nurses (PRR 1.9, 95%CI 1.3–2.8), among those with worst mental health (PRR 1.8, 95%CI 1.0–3.0), in those who reported incentives from piecework or bonuses (PRR1.4, 95%CI 1.0–2.0), and in those reporting job dissatisfaction (PRR 1.5, 95%CI 1.0–2.1). The strongest predictor of pain persistence was somatising tendency.
Our findings are consistent with a hazard of neck/shoulder pain from prolonged use of computer keyboards, although it is possible that the association is modified by health beliefs and expectations. They also indicate that the association of low mood with neck/shoulder pain extends to non-European populations, and is not entirely attributable to reverse causation. Psychosocial aspects of work appeared to have relatively weak impact.
Factors influencing work-related musculoskeletal disorders might differ in developing and developed countries.
To assess the prevalence and determinants of musculoskeletal pain in four occupational populations in Sri Lanka
As part of the international CUPID study, samples of postal workers, sewing machinists, nurses and computer operators were interviewed about pain in the past month at each of six anatomical sites, and about possible physical and psychosocial risk factors. Associations with prevalent pain were assessed by binomial regression.
Analysis was based on 852 participants (response rate 86%). Overall, the lower back was the most common site of pain, with one-month prevalence ranging from 12% in computer operators to 30% in nurses. Postal workers had the highest prevalence of shoulder pain (23%), but pain in the wrist/hand was relatively uncommon in all four occupational groups (prevalence rates from 8% to 9%). Low mood and tendency to somatise were each consistently associated with pain at all six sites. After adjustment for psychosocial risk factors, there was a higher rate of low back pain in nurses and postal workers than computer operators, a higher rate of shoulder pain in postal workers relative to other occupations, and a relatively low rate of knee pain in computer operators.
Rates of regional pain, especially at the wrist/hand, were lower than have been reported in western countries. As elsewhere, pain was strongly associated with low mood and somatising tendency. Differences in patterns of pain by occupation may reflect differences in physical activities.
Low back; neck; shoulder; elbow; wrist; knee; risk factor; psychosocial; low mood; somatising tendency
Experts disagree about the optimal classification of upper limb disorders (ULDs). To explore whether differential response to treatments offers a basis for choosing between case definitions, we analysed previously published research.
We screened 183 randomised controlled trials (RCTs) of treatments for ULDs, identified from the bibliographies of 10 Cochrane reviews, four other systematic reviews, and a search in Medline, Embase, and Google Scholar to June 2010. From these, we selected RCTs which allowed estimates of benefit (expressed as relative risks (RRs)) for >1 case definition to be compared when other variables (treatment, comparison group, follow-up time, outcome measure) were effectively held constant. Comparisons of RRs for paired case definitions were summarised by their ratios, with the RR for the simpler and broader definition as the denominator.
Two RCT reports allowed within-trial comparison of RRs and thirteen others allowed between-trial comparisons. Together these provided 17 ratios of RRs (five for shoulder treatments, 12 for elbow treatments, none for wrist/hand treatments). The median ratio of RRs was 1.0 (range 0.3 to 1.7; interquartile range 0.6 to 1.3).
Although the evidence base is limited, our findings suggest that for musculoskeletal disorders of the shoulder and elbow, clinicians in primary care will often do best to apply simpler and broader case definitions. Researchers should routinely publish secondary analyses for subgroups of patients by different diagnostic features at trial entry, to expand the evidence base on optimal case definitions for patient management.
National analyses of mortality in England and Wales have repeatedly shown excess deaths from pneumonia in welders. During 1979-1990 the excess was attributable largely to deaths from lobar pneumonia and pneumonias other than bronchopneumonia, limited to working-aged men, and apparent in other metal fume-exposed occupations. We assessed findings for 1991-2000 and compared the mortality pattern with that from asthma in occupations exposed to known respiratory sensitizers.
The Office of National Statistics supplied data on deaths by underlying cause among men aged 16-74 years in England and Wales during 1991-2000, including age and last held occupation. We abstracted data on pneumonia for occupations with exposure to metal fume and on asthma for occupations commonly reported to surveillance schemes as at risk of occupational asthma. We estimated expected numbers of deaths by applying age-specific proportions of deaths by cause in the population to the total deaths by age in each occupational group. Observed and expected numbers were compared for each cause of death.
Among working-aged men in metal fume-exposed occupations we found excesses of mortality from pneumococcal and lobar pneumonia (54 deaths vs. 27.3 expected) and from pneumonias other than bronchopneumonia (71 vs. 52.4), but no excess from these causes at older ages, or from bronchopneumonia at any age. The attributable mortality from metal fume (45.3 excess deaths) compared with an estimated 62.6 deaths from occupational asthma.
Exposure to metal fume is a material cause of occupational mortality. The hazard deserves far more attention than it presently receives.
Experts disagree about the optimal classification of upper limb disorders (ULDs). To explore whether differences in associations with occupational risk factors offer a basis for choosing between case definitions in aetiological research and surveillance, we analysed previously published research.
Eligible reports (those with estimates of relative risk (RR) for >1 case definition relative to identical exposures were identified from systematic reviews of ULD and occupation and by hand-searching five peer-review journals published between January 1990 and June 2010. We abstracted details by anatomical site of the case and exposure definitions employed and paired estimates of RR, for alternative case definitions with identical occupational exposures. Pairs of case definitions were typically nested, a stricter definition being a subset of a simpler version. Differences in RR between paired definitions were expressed as the ratio of RRs, using that for the simpler definition as the denominator.
We found 21 reports, yielding 320 pairs of RRs (82, 75 and 163 respectively at the shoulder, elbow, and distal arm). Ratios of RRs were frequently ≤1 (46%), the median ratio overall and by anatomical site being close to unity. In only 2% of comparisons did ratios reach ≥4.
Complex ULD case definitions (e.g. involving physical signs, more specific symptom patterns, and investigations) yield similar associations with occupational risk factors to those using simpler definitions. Thus, in population-based aetiological research and surveillance, simple case definitions should normally suffice. Data on risk factors can justifiably be pooled in meta-analyses, despite differences in case definition.
To explore the relationship between occupational exposures and lateral and medial epicondylitis and the effect of epicondylitis on sickness absence in a population sample of working aged adults.
This was a cross-sectional study of 9696 randomly selected adults aged 25-64 years involving a screening questionnaire and standardised physical examination. Age- and sex-specific prevalence rates of epicondylitis were estimated and associations with occupational risk factors explored.
Among 6038 respondents, 636 (11%) reported elbow pain in the last week. 0.7% of those surveyed were diagnosed with lateral epicondylitis and 0.6% with medial epicondylitis. Lateral epicondylitis was associated with manual work (OR 4.0, 95% CI 1.9-8.4). In multivariate analyses, repetitive bending/straightening elbow > 1 hour day was independently associated with lateral (OR 2.5, 95% CI 1.2-5.5) and medial epicondylitis (OR 5.1, 95% CI 1.8-14.3). 5% of adults with epicondylitis took sickness absence because of their elbow symptoms in the past 12 months (median 29 days).
Repetitive exposure to bending/straightening the elbow was a significant risk factor for medial and lateral epicondylitis. Epicondylitis is associated with prolonged sickness absence in 5% of affected working-aged adults.
lateral epicondylitis; medial epicondylitis; epidemiology; occupation; sickness absence