E C Harris

Chronic health problems and risk of accidental injury in the workplace: a systematic literature review

Objectives: To investigate whether common important health conditions and their treatments increase risks of occupational injury. Methods: A systematic search was conducted of MEDLINE, EMBASE and PsycINFO databases from inception to November 2006 employing terms for occupational injury, medications, and a broad range of diseases and impairments. Papers related solely to driving, alcohol, or substance abuse were excluded, as were studies that did not allow analysis of injury risk. For each paper that was retrieved we abstracted standard information on the population, design, exposure(s), outcome(s), response rates, confounders and effect estimates; and rated the quality of information provided. Results: We found 38 relevant papers (33 study populations): 16 studies were of cross-sectional design, 13 were case-control and 4 were prospective. The overall quality was rated as excellent for only two studies. Most commonly investigated were problems of hearing (15 studies), mental health (11 studies) and vision (10 studies). For impaired hearing, neurotic illness, diabetes, epilepsy and use of sedating medication there were moderate positive associations with occupational injury (odds ratios 1.5–2.0), but there were major gaps in the evidence base. Studies covering vision did not present risks by category of eye disease; no evidence was found on psychotic illness; for diabetes, epilepsy and cardiovascular disease there were remarkably few papers; studies seldom distinguished risks by sub-category of external cause or anatomical site and nature of injury; and exposures and outcomes were mostly ascertained by self-report at a single time point, with a lack of clarity about exposure timings. Conclusion: Improved research is needed to define the risks of occupational injury arising from common health complaints and treatments. Such research should delineate exposures and outcomes in more detail, and ensure by design that the former precede the latter.

Optimising case definitions of upper limb disorder for aetiological research and prevention: a review

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. We conclude that 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.

Mortality of workers exposed to ethylene oxide: extended follow up of a British cohort

Aims: To obtain further information about the risks of cancer associated with occupational exposure to ethylene oxide Methods: Follow up was extended by 13 years for a cohort of 2876 men and women with definite or potential exposure to ethylene oxide in the chemical industry or in hospital sterilising units. Subjects were traced through National Health Service and social security records, and their mortality was compared with that expected from rates in the national population by the person-years method. Results: Analysis was based on 565 deaths, of which 339 had occurred during the additional period of follow up. Mortality was close to or below expectation for all causes (565 deaths v 607.6 expected), all cancers (188 v 184.2), and for all specific categories of malignancy including stomach cancer (10 v 11.6), breast cancer (11 v 13.2), non-Hodgkin’s lymphoma (7 v 4.8), and leukaemia (5 v 4.6). All five deaths from leukaemia occurred in the subset of subjects with greatest potential for exposure to ethylene oxide, but even in this group the excess of deaths was small (2.6 expected). Conclusions: The balance of evidence from this and other epidemiological investigations indicates that any risk of human cancer from ethylene oxide is low, particularly at the levels of occupational exposure that have occurred in Britain over recent decades. This may reflect the capacity of human cells to repair DNA damage caused by the chemical, which is a potent genotoxin and animal carcinogen.

Work-related mortality in England and Wales, 1979–2000

Background 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 deaths in men aged 20–74 years during 1979–1980 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. 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. 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.

The role of mental health problems and common psychotropic drug treatments in accidental injury at work: a case-control study.

Objectives Mental illness and psychotropic drugs have been linked with workplace injury, but few studies have measured exposures and outcomes independently or established their relative timings. To address this shortcoming, we conducted a case–control study nested within a database prospectively recording injury consultations, diagnoses and drug prescriptions. Methods The Clinical Practice Research Datalink logs primary care data for 6% of the British population, coding all consultations (by the Read system) and drug prescriptions. We identified 1348 patients aged 16–64 years from this database who had consulted a family doctor or hospital over a 20-year period for workplace injury (cases, 479 diagnostic codes) and 6652 age, sex and practice-matched controls with no such consultation. Groups were compared in terms of consultations for mental health problems (1328 codes) and prescription of psychotropic drugs prior to the cases injury consultation using conditional logistic regression. Results In total, 1846 (23%) subjects had at least one psychiatric consultation before the index date and 1682 (21%) had been prescribed a psychotropic drug. The OR for prior mental health consultation was 1.44 (p<0.001) and that for psychotropic drug treatment was 1.57 (p<0.001). Risks were significantly elevated for several subclasses of mental health diagnosis (eg, psychosis, neurosis) and for each of the drug classes analysed. Assuming causal relationships, about 9–10% of all workplace injuries leading to medical consultation were attributable to mental illness or psychotropic medication. Conclusions Mental health problems and psychotropic treatments may account for an important minority of workplace injuries.

Evaluation of a case management service to reduce sickness absence

BACKGROUND 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 health care sector. AIMS To evaluate a new return to work service at an English hospital trust. METHODS The new service entailed intensive case management for staff who had been absent sick for longer than 4 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. RESULTS At the intervention trust, the proportion of 4-week absences that 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 1.5-20.0%). There was also a differential improvement in mean days of absence beyond 4 weeks, but this was not statistically significant (1.6 days per absence; 95% CI -7.2 to 10.3 days). CONCLUSIONS 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.

Epilepsy, diabetes mellitus and accidental injury at work

AIMS To assess the contribution of epilepsy and diabetes to occupational injury. METHODS The Clinical Practice Research Datalink logs primary care data for 6% of the British population, coding all consultations and treatments. Using this, we conducted a population-based case-control study, identifying patients aged 16-64 years, who had consulted over two decades for workplace injury, plus matched controls. By conditional logistic regression, we assessed risks for diabetes and epilepsy overall, several diabetic complications and indices of poor control, occurrence of status epilepticus and treatment with hypoglycaemic and anti-epileptic agents. RESULTS We identified 1348 injury cases and 6652 matched controls. A total of 160 subjects (2%) had previous epilepsy, including 29 injury cases, whereas 199 (2.5%) had diabetes, including 77 with eye involvement and 52 with a record of poor control. Odds ratios (ORs) for occupational injury were close to unity, both in those with epilepsy (1.07) and diabetes (0.98) and in those prescribed anti-epileptic or hypoglycaemic treatments in the previous year (0.87-1.16). We found no evidence of any injury arising directly from a seizure and no one had consulted about their epilepsy within 100 days before their injury consultation. Two cases and six controls had suffered status epilepticus (OR versus never had epilepsy 1.61). Risks were somewhat higher for certain diabetic complications (OR 1.44), although lower among those with eye involvement (OR 0.70) or poor diabetic control (OR 0.50). No associations were statistically significant. CONCLUSIONS No evidence was found that diabetes or epilepsy are important contributors to workplace injury in Britain.

Optimal case definitions of upper extremity disorder for use in the clinical treatment and referral of patients.

Experts disagree about the optimal classification of upper extremity disorders. To explore whether differential response to treatments offers a basis for choosing between case definitions, we analyzed previously published research.

Sleep disturbance and the older worker: findings from the Health and Employment after Fifty study

Objectives The aim of this study was to characterize the descriptive epidemiology of insomnia in midlife and explore the relative importance of different occupational risk factors for insomnia among older workers. Methods A questionnaire was mailed to all adults aged 50-64 years registered with 24 English general practices. Insomnia was defined as having at least one of four problems with sleep severely in the past three months. Subjects were also asked about employment conditions, feelings concerning work, and their health. Associations were assessed by logistic regression and population attributable fractions (PAF) calculated. Results Analysis was based on 8067 respondents (5470 in paid work), 18.8% of whom reported insomnia. It was more common among women, smokers, obese individuals, those living alone, and those in financial hardship, and less prevalent among the educated, those in South-East England, and those with friendships and leisure-time pursuits. Occupational risk factors included unemployment, shift working, lack of control and support at work, job insecurity, job dissatisfaction and several of its determinants (lacking a sense of achievement, feeling unappreciated, having difficult work colleagues, feeling unfairly criticized). Population burden of insomnia was associated more strongly with difficulties in coping with work demands, job insecurity, difficult colleagues, and lack of friendships at work [population attributable fraction (PAF) 15-33%] than shift work and lack of autonomy or support (PAF 5-7%). It was strongly associated with seven measures of poorer self-assessed health. Conclusions Employment policies aimed at tackling insomnia among older workers may benefit from focusing particularly on job-person fit, job security and relationships in the workplace.

Mortality from diabetes and ischaemic heart disease in textile workers

Background To explore explanations for elevated mortality from diabetes among male garment manufacturers and repairers in England and Wales during 1979-1990, analysis was extended by 10 years, looking also at other textile workers and at deaths from ischaemic heart disease (IHD). Methods Data on some 3.5 million deaths were used to compute proportional mortality ratios (PMRs) for diabetes and IHD, standardised for age and social class, in 10 textile-associated job groups, with additional analyses by place of birth for 1993–2000. Results Male mortality from diabetes was elevated in nine of the 10 textile jobs, with overall PMRs of 147 (95% CI 131 to 165) during 1979–90 and 170 (95% CI 144 to 199) during 1991–2000. Proportional mortality from IHD was also consistently high. Female 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 subcontinent (PMRs 353 and 139 in men; 262 and 130 in women). In men, the proportion of deceased textile workers born in the Indian subcontinent (11.4%) was much higher than for all occupations (1.8%), but not in women (1.1% vs 0.7%). PMRs for male textile workers standardised for place of birth were lower but still significantly elevated (133, 95% CI 110 to 159 for diabetes; 109, 95% CI 105 to 114 for IHD). Conclusions No obvious occupational hazard explains the increased risk specific to men across a wide range of textile occupations. One possible explanation is uncontrolled residual confounding related to place of birth. This could be tested through suitably designed morbidity surveys.