Background

The prevalence of knee osteoarthritis (OA) is rising and the search for interventions to mitigate risk is intensifying. This review considers the contribution of occupational activities to disease occurrence and the lessons for prevention.

Sources

Systematic search in Embase and Medline covering the period 1996 to November 2011.

Areas of agreement

Reasonably good evidence exists that physical work activities (especially kneeling, squatting, lifting, and climbing) can cause and/or aggravate knee OA. These exposures should be reduced where possible. Obese workers with such exposures are at additional risk of knee OA and should therefore particularly be encouraged to lose weight.

Areas of uncertainty/research need

Workplace interventions and policies to prevent knee OA have seldom been evaluated. Moreover, their implementation can be problematic. However, the need for research to optimise the design of work in relation to knee OA is pressing, given population trends towards extended working life.

Background

Changing demographics mean that many patients with large joint arthritis will work beyond traditional retirement age. This review considers the impact of knee osteoarthritis (OA) on work participation and the relation between work and knee replacement (TKR).

Sources

Two systematic searches in Embase and Medline, supplemented by three systematic reviews.

Areas of agreement

Probably, although evidence is limited, knee OA considerably impairs participation in work (labour force participation, work attendance and work productivity).

Areas of uncertainty/research need

Little is known about effective interventions (treatments, work changes and policies) to improve vocational participation in patients with knee OA; or how type of work affects long-term clinical outcomes (e.g. pain, function, the need for revision surgery) in patients with TKRs. The need for such research is pressing and opportune, as increasing numbers of patients with knee OA or TKR expect to work on.

Objective

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.

Methods

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.

Result

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).

Conclusion

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.

Introduction

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.

Methods

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.

Results

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.

Conclusion

Exposure to metal fume is a material cause of occupational mortality. The hazard deserves far more attention than it presently receives.

Background

Professional musicians may have high rates of musculoskeletal pain, but few studies have analysed risks by work activities or the psychosocial work environment.

Aims

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.

Methods

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.

Results

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.

Conclusions

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.

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Objectives

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.

Methods

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.

Results

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).

Conclusions

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.

This systematic review assesses the effectiveness of interventions in community and workplace settings to reduce sickness absence and job loss in workers with musculoskeletal disorders (MSDs). Relevant studies (randomised controlled trials (RCTs) and cohort studies published since 1990) were identified by screening citations in 35 earlier systematic reviews and from searches of Medline and Embase to April 2010. Among 42 studies (54 reports) including 34 RCTs, 27 assessed return to work, 21 duration of sickness absence, and five job loss. Interventions included exercise therapy, behavioural change techniques, workplace adaptations and provision of additional services. Studies were typically small (median sample size 107 (inter-quartile range (IQR) 77 to 148) and limited in quality. Most interventions were reported as beneficial: the median relative risk (RR) for return to work was 1.21 (IQR 1.00 – 1.60) and that for avoiding MSD-related job loss, 1.25 (IQR 1.06-1.71); the median reduction in sickness absence was 1.11 (IQR 0.32 to 3.20) days/month. However, effects were smaller in the larger and better quality studies, suggesting publication bias. No intervention was clearly superior to others, although effort-intensive interventions were less effective than simple ones. No cost-benefit analyses established statistically significant net economic benefits. Given that benefits are small and of doubtful cost-effectiveness, employers’ practice should be guided by their value judgements about the uncertainties. Expensive interventions should be implemented only with rigorous cost-benefit evaluation planned from the outset. Future research should focus on the cost-effectiveness of simple low cost interventions, and further explore impacts on job retention.

Background

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.

Methods/Principal Findings

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).

Conclusions/Significance

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.

Background

Varying work schedules are suspected of increasing risks to pregnant women and to fetal wellbeing. In particular, maternal hormonal disturbance arising from sleep deprivation or circadian rhythm disruption might impair fetal growth or lead to complications of pregnancy. Two independent meta-analyses (from 2000 and 2007) reported a small adverse effect of shift work on the risk of preterm delivery (PTD). However, these reviews were based on few high quality studies.

Objectives

To provide an updated review of the associations of shift work with PTD, low birthweight (LBW), small for gestational age (SGA), and pre-eclampsia.

Search strategy and Selection Criteria

We conducted a systematic search of MEDLINE using combinations of keywords and MeSH terms.

Data Collection and Analysis

for each relevant paper we abstracted standard details, used to summarize design features and rate methodological quality. We calculated pooled estimates of relative risk (RR) in random-effect meta-analyses.

Main Results

We retrieved 23 relevant studies. The pooled estimate of RR for PTD was 1.16 (95%CI 1.00-1.33, 16 studies), but when five reports of poorer methodological quality were excluded, the estimated RR reduced to 1.03 (95%CI 0.93-1.14). We also observed increased RRs for LBW (1.27, 95%CI 0.93-1.74) and for SGA (1.12, 95%CI 1.03-1.22), which varied little by study quality. Little evidence was found on pre-eclampsia.

Conclusions

These findings suggest that overall, any risk of PTD, LBW, or SGA arising from shift-work in pregnancy is small.

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.

Background

National initiatives to prevent and/or manage sickness absence require a database from which trends can be monitored.

Aims

To evaluate the information provided by surveillance schemes and publicly available datasets on sickness absence nationally from musculoskeletal disorders (MSDs).

Methods

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.

Results

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.

Conclusions

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.

Summary

Background

It has been argued that in case-control studies, controls should be drawn from the base population that gives rise to the cases. In designing a study of occupational injury and risks arising from long-term illness and prescribed medication, we lacked data on subjects’ occupation, without which employed cases (typically in manual occupations) would be compared with controls from the general population, including the unemployed and a higher proportion of white-collar professions. Collecting the missing data on occupation would be costly. We estimated the potential for bias if the selection rule were ignored.

Methods

We obtained published estimates of the frequencies of several exposures of interest (diabetes, mental health problems, asthma, coronary heart disease) in the general population, and of the relative risks of these diseases in unemployed vs. employed individuals and in manual vs. non-manual occupations. From these we computed the degree of over- or underestimation of exposure frequencies and exposure odds ratios if controls were selected from the general population.

Results

The potential bias in the odds ratio was estimated as likely to fall between an underestimation of 14% and an overestimation of 36.7% (95th centiles). In fewer than 6% of simulations did the error exceed 30%, and in none did it reach 50%.

Conclusions

For the purposes of this study, in which we were interested only in substantial increases in risk, the potential for selection bias was judged acceptable. The rule that controls should come from the same base population as cases can justifiably be broken, at least in some circumstances.

Background

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.

Methods

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.

Results

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.

Conclusions

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.

Objectives

Musculoskeletal pain is associated with occupational physical activities and psychosocial risk factors. We evaluated the relative importance of work-related and psychological determinants of the number of anatomical sites affected by musculoskeletal pain in a cross-sectional survey.

Methods

The survey focused on musculoskeletal pain in six body regions (low-back, neck, shoulder, elbow, wrist/hand and knee) among 224 nurses, 200 office workers and 140 postal clerks in Crete (response rate 95%). Information was collected about demographic characteristics, occupational physical load, psychosocial aspects of work, perceptions about causes of pain, mental health, tendency to somatize, and experience of pain in the past 12 months. Poisson regression was used to assess associations of risk factors with the number of painful anatomical sites and interactions were explored using classification and regression trees (CART).

Results

Two-thirds of the study sample reported pain in at least two body sites during the past 12 months, and in 23%, more than three sites were affected. The number of painful anatomical sites was strongly related to both physical load at work and somatizing tendency (with relative risks increased five-fold or more for frequent and disabling multisite pain) , and was also significantly associated with work-related psychosocial factors, and beliefs about work causation. The CART analysis suggested that in the population studied, the leading determinant of the number of painful body sites was somatizing tendency.

Conclusions

In the population studied, pain at multiple anatomical sites is common, and is strongly associated with somatizing tendency, which may have a more important influence on multi-site pain than on pain that is limited to a single anatomical site.

AIms

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.

Methods

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.

Results

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).

Conclusions

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.

Background

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.

Aims

To explore reasons for this change.

Methods

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.

Results

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).

Conclusions

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.

Background

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.

Methods

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).

Results

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.

Conclusions

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.

Objectives

To assess the prevalence and correlates of regional pain and associated disability in four groups of Japanese workers.

Methods

As part of a large international survey of musculoskeletal symptoms (the CUPID study), samples of nurses, office workers, sales/marketing personnel and transportation operatives in Japan completed a self-administered questionnaire (response rate 83%). The questionnaire covered experience of pain in six anatomical regions, associated disability and sickness absence, and various possible occupational and psychosocial risk factors for these outcomes. Associations with risk factors were assessed by logistic regression.

Results

Analysis was based on 2290 subjects. Rates of regional pain were generally less than have been reported in the UK, with a particularly low prevalence of wrist/hand pain among office workers (6% in the past month). The strongest and most consistent risk factor for regional pain in the past month was tendency to somatise (odds ratios (95% confidence intervals) for report of ≥2 v 0 distressing somatic symptoms 3.1 (2.4-4.0) for low back pain, 2.8 (2.1-3.8) for shoulder pain, and 2.5 (1.6-4.1) for wrist/hand pain). Sickness absence for regional pain complaints in the past year was reported by 5% of participants, the major risk factor for this outcome being absence during the same period for other medical reasons (OR 3.7, 95%CI 2.4-5.8).

Conclusions

Japanese office workers have markedly lower rates of wrist/hand pain than their UK counterparts. In Japan, as in Western Europe, somatising tendency is a major risk factor for regional pain. Sickness absence attributed to regional pain complaints appears to be much less common in Japan than in the UK, and to be driven principally by a general propensity to take sickness absence.

Background

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).

Methods

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.

Results

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).

Conclusions

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.

Carpal Tunnel Syndrome is a fairly common condition in working-aged people, sometimes caused by physical occupational activities, such as repeated and forceful movements of the hand and wrist or use of hand-held powered vibratory tools. Symptoms may be prevented or alleviated by primary control measures at work and some cases of disease are compensable. Following a general description of the disorder, its epidemiology, and some of the difficulties surrounding diagnosis, this review focuses on the role of occupational factors in causation of CTS and factors that can mitigate risk. Areas of uncertainty, debate and research interest are emphasised where relevant.

Study design

Systematic review and meta-analysis

Objective

To assess how confidently LBP can be attributed to abnormalities on MRI, and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical low back pain (LBP) in epidemiological research.

Summary of background data

Most epidemiological studies of mechanical LBP have defined cases only by reported symptoms, but it is possible that the potency of causes differs according to whether or not there is demonstrable underlying spinal pathology.

Methods

We reviewed the published literature on MRI abnormalities, looking for data on the repeatability of their assessment, their prevalence in people free from LBP, and their association with LBP. Where data were sufficient, we calculated a summary estimate of prevalence in people without LBP and a meta-estimate of the odds ratio for the association with LBP. A formula was then applied to estimate the corresponding prevalence rate ratio (PRR), assuming three possible prevalence rates for LBP in the general population.

Results

Data were most extensive for disc protrusion, nerve root displacement/compression, disc degeneration and high intensity zone (HIZ), all of which could be assessed repeatably. All were associated with LBP, meta-estimates of odds ratios ranging from 2.3 (nerve root displacement/compression) to 3.6 (disc protrusion). However, even for disc protrusion, estimates of the corresponding PRRs were mostly less than two.

Conclusion

MRI findings of disc protrusion, nerve root displacement/compression, disc degeneration and HIZ are all associated with LBP, but individually, none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology. This limits their value in refining epidemiological case definitions for LBP.

Objectives

To investigate risks of physical activity at work by pregnancy trimester, including the effects on head and abdominal circumference.

Method

At 34 weeks gestation we interviewed 1327 mothers from the prospective Southampton Women’s Survey (SWS); we asked about their activities (working hours, standing/walking, kneeling/squatting, trunk bending, lifting and night shifts) in jobs held at each of 11, 19 and 34 weeks gestation, and subsequently ascertained four birth outcomes – preterm delivery, small for gestational age (SGA) and reduced head or abdominal circumference – blinded to employment history.

Results

Risk of preterm delivery was elevated nearly three-fold in women whose work at 34 weeks entailed trunk bending for >1 hour/day. Small head circumference was more common in babies born to women who worked for >40 hours/week. However, no statistically significant associations were found with SGA or small abdominal circumference, and pre-term delivery showed little association with long working hours, lifting, standing, or shift work.

Conclusions

A need exists for more research on trunk bending late in pregnancy, and on the relation of work to reduced head circumference. Our findings on several other occupational exposures common among pregnant workers are reassuring.