We assessed the evidence relating pre-term delivery (PTD), low birthweight, small for gestational age (SGA), pre-eclampsia and gestational hypertension to five occupational exposures (working hours, shift work, lifting, standing and physical workload). We conducted a systematic search in MEDLINE and EMBASE (1966–2011), updating a previous search with a further six years of observations.
As before, combinations of keywords and MeSH terms were used. Each relevant paper was assessed for completeness of reporting and potential for important bias or confounding, and its effect estimates abstracted. Where similar definitions of exposure and outcome existed we calculated pooled estimates of relative risk in meta-analysis.
Analysis was based on 86 reports (32 cohort investigations, 57 with usable data on PTD, 54 on birthweight and 11 on pre-eclampsia/gestational hypertension); 33 reports were new to this review. For PTD, findings across a substantial evidence base were generally consistent, effectively ruling out large effects (e.g. RR>1.2). Larger and higher quality studies were less positive, while meta-estimates of risk were smaller than previously and best estimates pointed to modest or null effects (RR 1.04 to 1.18). For SGA, the position was similar but meta-estimates were even closer to the null (eight of nine RRs ≤ 1.07). For pre-eclampsia/gestational hypertension the evidence base remains insufficient.
The balance of evidence is against large effects for the associations investigated. As the evidence base has grown, estimates of risk in relation to these outcomes have become smaller.
pregnancy; occupation; review; meta-analysis
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 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 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
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.
Professional musicians may have high rates of musculoskeletal pain, but few studies have analysed risks by work activities or the psychosocial work environment.
To assess the prevalence and impact of musculoskeletal pain, and its relation to playing conditions, mental health and performance anxiety, in musicians from leading British symphony orchestras.
Musicians from six professional orchestras completed a questionnaire concerning their orchestral duties and physical activities at work; mental health (somatising tendency, mood, demand, support and control at work, performance anxiety); and regional pain in the past four weeks and past 12 months. Prevalence rates were estimated by anatomical site, and associations with risk factors assessed by logistic regression.
Responses were received from 243 musicians (51% of those approached), among whom 210 (86%) reported regional pain in the past 12 months, mainly affecting the neck, low-back, and shoulders. Risks tended to be higher in women, in those with low mood, and especially in those with high somatising scores. Only weak associations were found with psychosocial work stressors and performance anxiety. However, risks differed markedly by instrument category. Relative to string players, the odds of wrist/hand pain were raised 2.9-fold in wind players, but 60% lower in brass players, while the odds of elbow pain were 50% lower among wind and brass players.
Musculoskeletal pain is common in elite professional musicians. A major personal risk factor is somatising tendency, but performance anxiety has less impact. Risks differ substantially by instrument played, offering pointers towards prevention.
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.
We hypothesised that the relative importance of physical and psychological risk factors for mechanical low back pain (LBP) might differ importantly according to whether there is underlying spinal pathology, psychological risk factors being more common in patients without demonstrable pathology. If so, epidemiological studies of LBP could benefit from tighter case definitions. To test the hypothesis, we used data from an earlier case-control study on patients with mechanical LBP who had undergone magnetic resonance imaging (MRI) of the lumbosacral spine. MRI scans were classified for the presence of high-intensity zone (HIZ), disc degeneration, disc herniation, and nerve root displacement/compression. Information about symptoms and risk factors was elicited by postal questionnaire. Logistic regression was used to assess associations of MRI abnormalities with symptoms and risk factors, which were characterised by odds ratios (ORs) and 95% confidence intervals (CIs). Among 354 patients (52% response), 306 (86.4%) had at least 1, and 63 (17.8%) had all 4 of all MRI abnormalities. Radiation of pain below the knee (280 patients) and weakness or numbness below the knee (257 patients) were both associated with nerve root deviation/compression (OR 2.5, 95% CI 1.4 to 4.5; and OR 1.8, 95% CI 1.1 to 3.1, respectively). However, we found no evidence for the hypothesised differences in risk factors between patients with and without demonstrable spinal pathology. This suggests that when researching the causes and primary prevention of mechanical LBP, there may be little value in distinguishing between cases according to the presence or absence of the more common forms of potentially underlying spinal pathology.
Low back pain; MRI; high intensity zone; disc degeneration; disc prolapse; nerve root compression; symptoms; risk factors
National initiatives to prevent and/or manage sickness absence require a database from which trends can be monitored.
To evaluate the information provided by surveillance schemes and publicly available datasets on sickness absence nationally from musculoskeletal disorders (MSDs).
A grey literature search was undertaken using the search engine Google, supplemented by leads from consultees from academia, industry, employers, lay interest groups and government. We abstracted data on the outcomes and populations covered, and made quantitative estimates of MSD-related sickness absence, overall and, where distinguishable, by sub-diagnosis. The coverage and limitations of each source were evaluated.
Sources included the Labour Force Survey (LFS) and its Self-reported Work-related Illness survey module; the THOR-GP surveillance scheme; surveys by national and local government; surveys by employers’ organisations; and a database of benefit statistics. Each highlighted MSDs as a leading cause of sickness absence. Data limitations varied by source, but typically included lack of diagnostic detail and restriction of focus to selected subgroups (e.g. work-ascribed or benefit-awarded cases, specific employment sectors). Additionally, some surveys had very low response rates, were completed only by proxy respondents, or ranked only the perceived importance of MSD-related sickness absence, rather than measuring it.
National statistics on MSD-related sickness absence are piecemeal and incomplete. This limits capacity to plan and monitor national policies in an important area of public health. Simple low-cost additions to the LFS would improve the situation.
National analyses of occupational mortality provide information on the most severe diseases and injuries caused by work, enabling preventive actions to be targeted and evaluated. To explore time trends in deaths attributable to work in England and Wales, and identify priorities for prevention, we conducted a proportional analysis of mortality by occupation over a 22-year period.
Analysis was based on the 93% of deaths in men aged 20-74 years during 1979-80 and 1982-2000 with a recorded occupation. Proportional mortality ratios, standardised for age and social class, were calculated for pre-specified combinations of occupation and cause of death, for which excess mortality could reasonably be attributed to work. Differences between observed and expected numbers of deaths by cause and occupation were expressed as annual excess death rates, and as fractions of all deaths in relevant occupations.
Mortality attributable to work declined substantially over the period of study, with total excess death rates of 733.2 per year during 1979-1990 and 471.7 per year during 1991-2000. The largest contributing hazards were chronic obstructive pulmonary disease and pneumoconiosis in coal miners, pleural cancer from asbestos, and motor vehicle accidents in lorry drivers. In contrast to most other hazards, there was no clear decline in excess mortality attributable to asbestos, or in deaths from sino-nasal cancer associated with exposure to wood dust. Risk of work-related mortality was particularly high in coal miners and aircraft flight deck officers among whom approximately 4% of deaths were attributable to occupation.
The overall decline in mortality attributable to work is likely to reflect reduced employment in more hazardous occupations, as well as improvements in working conditions. It is imperative to ensure that occupational exposures to asbestos and wood dust are now adequately controlled. Further research is needed on accidents involving lorries with the aim of developing more effective strategies for the prevention of injury.
Work in commercial fishing is physically demanding and hazardous, but unlike merchant seamen, fishermen are not required to hold a certificate of medical fitness.
To investigate the case for regulatory medical standards for commercial fishermen, and to identify priorities for the prevention and management of occupational injuries at sea.
We surveyed a convenience sample of fishermen at three major fishing ports in South-west England, using a standardised, interview-administered questionnaire.
Interviews were completed by 210 (68%) of 307 fishermen approached. Over their careers, 56 subjects (27%) had been returned to shore as an emergency for medical reasons, a rate of 14.6 (95% CI 11.5-18.2) per 1000 man-years. Most emergency evacuations were for acute injuries, and only five were for illness. A few participants suffered from chronic disease that would call into question their fitness to go to sea. Fifty five fishermen had suffered injuries in the past 12 months, including 12 that had caused loss of more than three days from work. Subjects had self-stitched four of 15 reported hand lacerations, while others had been bound with “Gaffer” tape.
Prevention of hand lacerations should be a high priority, with first aid training and equipment for fishing crews to improve their care when prevention fails. No firm conclusions can be drawn about the value of regular medical screening for commercial fishermen, but such screening should be considered a lower priority than accident prevention.
Fishermen; evacuation; health screening; injury; laceration
To identify opportunities for targeted prevention, we explored differences in occupational mortality from diseases and injuries related to alcohol consumption, sexual habits and drug abuse.
Using data on all deaths among men and women aged 16-74 years in England and Wales during 1991-2000, we derived age- and social class-standardised proportional mortality ratios (PMRs) by occupation for cause of death categories defined a priori as potentially related to alcohol consumption, sexual habits or drug abuse.
The highest mortality from alcohol-related diseases and injuries was observed in publicans and bar staff (both sexes), and in male caterers, cooks and kitchen porters, and seafarers. Male seafarers had significantly elevated PMRs for cirrhosis (179), “other alcohol-related diseases” (275), cancers of the liver (155), oral cavity (275) and pharynx (267), and injury by fall on the stairs (187). PMRs for HIV/AIDS were particularly high in tailors and dressmakers (918, 95%CI 369-1890, in men; 804, 95%CI 219-2060, in women) and male hairdressers (918, 95%CI 717-1160). Most jobs with high mortality from HIV/AIDS also had more deaths than expected from viral hepatitis. Of seven jobs with significantly high PMRs for both drug dependence and accidental poisoning by drugs, four were in the construction industry (male painters and decorators, bricklayers and masons, plasterers, and roofers and glaziers).
Our findings highlight major differences between occupations in mortality from diseases and injuries caused by alcohol, sexual habits and drug abuse. Priorities for preventive action include alcohol-related disorders in male seafarers and drug abuse in construction workers.
Occupation; alcohol; drug abuse; HIV; AIDS
An unusual inflammation of the pinna has been reported to occur in some sheep farmers at the time of lambing.
To explore the prevalence of this disorder and its possible causal associations.
While on attachment to sheep farms during lambing, veterinary students used a standardised questionnaire to interview a sample of farmers about their work, and about symptoms of skin inflammation in their hands, face and ears.
Interviews were completed by 76 (67%) of the farmers approached. Among 74 farmers who had carried out lambing, three (4%, 95% CI 1% to 11%) had experienced temporally related ear symptoms, all on multiple occasions. No farmers with ear symptoms had ever been involved in calving or farrowing, and no ear symptoms were reported in relation to shearing or dipping sheep. There was also an excess of hand symptoms related to lambing outdoors (24% of those who had done such work) and indoors (also 24%), compared with other farming activities.
Our findings suggest that temporally related ear inflammation occurs in at least 1% of farmers who carry out lambing, but not in association with the other farming activities investigated. Lambing appears to be associated also with hand inflammation, but the pathology may differ from that in the pinna.
Farming; sheep; lambing; ear; hand; skin; inflammation
Since the early 1990s, rates of incapacity benefit (IB) in Britain for musculoskeletal complaints have declined, and they have been overtaken by mental and behavioural disorders as the main reason for award of IB.
To explore reasons for this change.
Using data supplied by the Department for Work and Pensions, we analysed trends in the ratio of new IB awards for mental and behavioural disorders to those for musculoskeletal disorders during 1997-2007 by Government region.
In Great Britain overall, the above ratio more than doubled over the study period, as a consequence of falling numbers of new awards for musculoskeletal disorders. The extent to which the ratio increased was smallest in London (50%) and South-East England (56%), and was progressively larger in more northerly regions (>150% in North-East England and Scotland).
The differences in trends between regions seem too large to be explained by differential changes in working conditions, patterns of employment, or the rigour with which claims were assessed. An alternative explanation could be that the main driver for the trends has been culturally determined changes in health beliefs and expectations, and that these cultural changes began in London and the South-East, only later spreading to other parts of Britain.
social security; incapacity; mental; musculoskeletal; trends; health beliefs
It is possible that clinical outcome of low back pain (LBP) differs according to the presence or absence of spinal abnormalities on magnetic resonance imaging (MRI), in which case there could be value in using MRI findings to refine case definition of LBP in epidemiological research. We therefore conducted a longitudinal study to explore whether spinal abnormalities on MRI for LBP predict prognosis after 18 months.
A consecutive series of patients aged 20-64 years, who were investigated by MRI because of mechanical LBP (median duration of current episode 16.2 months), were identified from three radiology departments, and those who agreed completed self-administered questionnaires at baseline and after a mean follow-up period of 18.5 months (a mean of 22.2 months from MRI investigation). MRI scans were assessed blind to other clinical information, according to a standardised protocol. Associations of baseline MRI findings with pain and disability at follow-up, adjusted for treatment and for other potentially confounding variables, were assessed by Poisson regression and summarised by prevalence ratios (PRs) with their 95% confidence intervals (CIs).
Questionnaires were completed by 240 (74%) of the patients who had agreed to be followed up. Among these 111 men and 129 women, 175 (73%) reported LBP in the past four weeks, 89 (37%) frequent LBP, and 72 (30%) disabling LBP. In patients with initial disc degeneration there was an increased risk of frequent (PR 1.3, 95%CI 1.0-1.9) and disabling LBP (PR 1.7, 95%CI 1.1-2.5) at follow-up. No other associations were found between MRI abnormalities and subsequent outcome.
Our findings suggest that the MRI abnormalities examined are not major predictors of outcome in patients with LBP. They give no support to the use of MRI findings as a way of refining case definition for LBP in epidemiological research.
To explore possible explanations for elevated mortality from diabetes among male garment manufacturers and repairers in England and Wales during 1979-1990, we extended analysis by 10 years, looking also at other textile workers and at deaths from ischaemic heart disease (IHD).
We used data on some 3.5 million deaths to compute proportional mortality ratios (PMRs) for diabetes and IHD, standardised for age and social class, in 10 job groups concerned with manufacture of, or work with, textiles. For 1993-2000, we carried out additional analyses by place of birth.
Among men, mortality from diabetes was elevated in nine of the 10 textile job groups, with overall PMRs of 147 (95%CI 131-165) during 1979-90 and 170 (95%CI 144-199) during 1991-2000. Proportional mortality from IHD was also consistently high, although to a lesser extent. In female textile workers, mortality from both diseases was close to that for other occupations. In both sexes, mortality from diabetes and IHD was increased among people born in the Indian sub-continent (PMRs 353 and 139 in men; 262 and 130 in women). In men, the proportion of deceased textile workers who had been born in the Indian sub-continent (11.4%) was much higher than for all occupations (1.8%), but there was no similar differential for women (1.1% v 0.7%). When PMRs for male textile workers were standardised for place of birth, they were lower, but still significantly elevated (133, 95% CI 110-159 for diabetes and 109, 95% CI 105-114 for IHD).
There is no obvious occupational hazard that could explain an increased risk across such a wide range of textile occupations that is specific to men. One possible explanation is uncontrolled residual confounding related to place of birth. This could be tested through suitably designed morbidity surveys.
mortality; occupation; diabetes; ischaemic heart disease; textile workers; India; immigrants
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
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 CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.
A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).
The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively.
To quantify the variation in rates of absence due to 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 (92–1017 per occupational group). Additionally, 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 tenfold. 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.
international; risk factors; time pressure