Feasibility and sustainability of working in different types of jobs after total hip arthroplasty: analysis of longitudinal data from two cohorts.

OBJECTIVES: To investigate the rates of return to work and workability among working-age people following total hip arthroplasty (THA). METHODS: Participants from the Geneva Arthroplasty Registry and the Clinical Outcomes for Arthroplasty Study aged 18-64 years when they had primary THA and with at least 5 years' follow-up were mailed a questionnaire 2017-2019. Information was collected about preoperative and post-THA employment along with exposure to physically demanding activities at work or in leisure. Patterns of change of job were explored. Survival analyses using Cox proportional hazard models were created to explore risk factors for having to stop work because of difficulties with the replaced hip. RESULTS: In total, 825 returned a questionnaire (response 58%), 392 (48%) men, mean age 58 years, median follow-up 7.5 years post-THA. The majority (93%) of those who worked preoperatively returned to work, mostly in the same sector but higher rates of non-return (36%-41%) were seen among process, plant and machine operatives and workers in elementary occupations. 7% reported subsequently leaving work because of their replaced hip and the risk of this was strongly associated with: standing >4 hours/day (HR 3.81, 95% CI 1.62 to 8.96); kneeling/squatting (HR 3.32, 95% CI 1.46 to 7.55) and/or carrying/lifting ≥10 kg (HR 5.43, 95% CI 2.29 to 12.88). CONCLUSIONS: It may be more difficult to return to some (particularly physically demanding) jobs post-THA than others. Rehabilitation may need to be targeted to these types of workers or it may be that redeployment or job change counselling are required.

Recent UK retirees' views about the work-related factors which influenced their decision to retire: a qualitative study within the Health and Employment After Fifty (HEAF) cohort.

BACKGROUND: Lower birth rates and increasing longevity have resulted in ageing populations in European countries. These demographic changes place challenges on pension provision as numbers of those who are economically inactive and retired increase relative to those in paid work. Therefore, governments need workers to postpone retirement and work to older ages. Whilst health and wealth are important in retirement decision-making, considerably less is known about the effects of workplace factors. The aim of this study was to explore the views of recent UK retirees about the role that work-related factors played in their decision to retire. METHODS: This qualitative study was nested within the Health and Employment After Fifty (HEAF) cohort. People who had retired 3-6 years previously (not for health reasons) were purposively sampled to obtain the views of men and women from a range of socio-economic backgrounds and jobs. Semi-structured interviews were carried out by telephone using a pre-defined topic guide. Interviews were audio-recorded, transcribed and analysed thematically. RESULTS: Seventeen interviews were conducted. Thematic analysis showed that retirement decisions were complex and multi-factorial but that work-related factors contributed to decision-making in two main ways. First, some work factors pushed participants towards retirement. These were perceptions that: workplace change had affected the way they were valued or increased pressure on them; work demands, including commuting, had intruded excessively on personal time, effects that were exacerbated by modern technology; work was draining, isolating or under-appreciated; and /or that work was causing physical strain or discomfort relative to their perception of their capacity. In contrast, work factors could also cause participants to pull back towards work, particularly: autonomy; supportive work colleagues; a sense of being appreciated; and perceived job flexibility. CONCLUSIONS: Recent retirees explained that their decision to retire was multi-factorial but work-related factors contributed importantly. Potentially, employers could: review workers' perceptions about their work; their capacity in relation to job demands; increase flexibility; and facilitate a supportive work community to encourage longer working lives.

Physical work exposure matrix for use in the UK Biobank.

BACKGROUND: UK Biobank (UKB) is a large prospective cohort capturing numerous health outcomes, but limited occupational information (job title, self-reported manual work and occupational walking/standing). AIMS: To create and evaluate validity of a linkage between UKB and a job exposure matrix for physical work exposures based on the US Occupational Information Network (O*NET) database. METHODS: Job titles and UK Standard Occupational Classification (SOC) codes were collected during UKB baseline assessment visits. Using existing crosswalks, UK SOC codes were mapped to US SOC codes allowing linkage to O*NET variables capturing numerous dimensions of physical work. Job titles with the highest O*NET scores were assessed to evaluate face validity. Spearman's correlation coefficients were calculated to compare O*NET scores to self-reported UKB measures. RESULTS: Among 324 114 participants reporting job titles, 323 936 were linked to O*NET. Expected relationships between scores and self-reported measures were observed. For static strength (0-7 scale), the median O*NET score was 1.0 (e.g. audiologists), with a highest score of 4.88 for stone masons and a positive correlation with self-reported heavy manual work (Spearman's coefficient = 0.50). For time spent standing (1-5 scale), the median O*NET score was 2.72 with a highest score of 5 for cooks and a positive correlation with self-reported occupational walking/standing (Spearman's coefficient = 0.56). CONCLUSIONS: While most jobs were not physically demanding, a wide range of physical work values were assigned to a diverse set of jobs. This novel linkage of a job exposure matrix to UKB provides a potentially valuable tool for understanding relationships between occupational exposures and disease.

How does job dissatisfaction interact with self-rated health in determining the risk of health-related job loss? Prospective findings from the Health and Employment After Fifty (HEAF) study.

OBJECTIVES: Health and job satisfaction are key independent determinants of ability to work to older ages. We investigated the interaction of these two important factors on health-related job loss (HRJL) over 2 years of follow-up comparing male and female older workers. METHODS: A population sample of adults aged 50-64 years, recruited from 24 English general practices in the Health and Employment After Fifty (HEAF) study, completed questionnaires at baseline with follow-ups at 12 and 24 months. Multiple-record Cox proportional hazards models were performed to explore the main effects of, and potential interactions between, job satisfaction and self-rated health (SRH) as predictors of time to first HRJL. RESULTS: Of the initial 8134 participants, 5143 were ever in work in the study period. Among men, 5.7% and 14.3% reported job dissatisfaction (those in good and poor SRH, respectively), while among women these percentages were 4.6 and 12.9. HRJL was reported by 106 men and 176 women. Men in good health dissatisfied with their job had a sixfold (HR=6.4; 95% CI 3.3 to 12.4) increased risk of HRJL compared with men satisfied with their job (significant multiplicative interaction). Women dissatisfied with their job were more likely to have an HRJL within 2 years of follow-up irrespective of their SRH. CONCLUSIONS: SRH and job dissatisfaction have important individual effects on the risk of stopping work for health among older workers. These findings point to the importance of job satisfaction in reducing health-related exit from paid work among older workers.

Relationships between informal caregiving, health and work in the Health and Employment After Fifty study, England.

BACKGROUND: To investigate the prevalence of caregiving and its relationship with work, health and socio-economic circumstances in the Health and Employment After Fifty (HEAF) study. METHODS: The HEAF study comprises 8134 men and women aged 50-64 years recruited from 24 general practices. Socio-demographic, lifestyle and health characteristics and hours per week giving personal care were elicited by postal questionnaire. Objective clinical information about diagnoses/medications was retrieved from health records. Work-related and health risk factors for intense caring responsibilities (≥20 h/week vs. no hours) were explored using logistic regression with adjustment for age and social class. RESULTS: In all, 644 (17%) men and 1153 (26%) women reported caring responsibilities, of whom 93 and 199 were intense caregivers, who were more likely to be socio-economically disadvantaged; less likely to be working and, if combining caring with working (41 men and 90 women), more likely to be part-time/working shifts, than non-carers. Men caring ≥20 h/week were more likely to have COPD and to report musculoskeletal pain, poor/fair self-rated health, depression and sleep problems. Among working women, caring ≥20 h/week was associated with these same health outcomes and also with a doctor-diagnosed mental health problem or musculoskeletal pain in the previous year. CONCLUSIONS: Caregiving is common and unequal in the HEAF cohort, with more high-intensity informal care provided by those with greater levels of socio-economic deprivation, which could affect their employment and health. Caregivers need support to lead long, healthy lives, rather than becoming care needers themselves. Employers and governments need to take caregiving into account and support it actively.

Frailty, prefrailty and employment outcomes in Health and Employment After Fifty (HEAF) Study.

OBJECTIVES: Demographic changes are requiring people to work longer. No previous studies, however, have focused on whether the 'frailty' phenotype (which predicts adverse events in the elderly) is associated with employment difficulties. To provide information, we assessed associations in the Health and Employment After Fifty Study, a population-based cohort of 50-65-year olds. METHODS: Subjects, who were recruited from 24 English general practices, completed a baseline questionnaire on 'prefrailty' and 'frailty' (adapted Fried criteria) and several work outcomes, including health-related job loss (HRJL), prolonged sickness absence (>20 days vs less, past 12 months), having to cut down substantially at work and difficulty coping with work's demands. Associations were assessed using logistic regression and population attributable fractions (PAFs) were calculated. RESULTS: In all, 3.9% of 8095 respondents were classed as 'frail' and 31.6% as 'prefrail'. Three-quarters of the former were not in work, while 60% had left their last job on health grounds (OR for HRJL vs non-frail subjects, 30.0 (95% CI 23.0 to 39.2)). Among those in work, ORs for prolonged sickness absence, cutting down substantially at work and struggling with work's physical demands ranged from 10.7 to 17.2. The PAF for HRJL when any frailty marker was present was 51.8% and that for prolonged sickness absence was 32.5%. Associations were strongest with slow reported walking speed. Several associations were stronger in manual workers than in managers. CONCLUSIONS: Fried frailty symptoms are not uncommon in mid-life and are strongly linked with economically important adverse employment outcomes. Frailty could represent an important target for prevention.

Mortality from multiple sclerosis in British military personnel.

BACKGROUND: While analysing trends in occupational mortality in England and Wales, we noticed an unexpectedly elevated proportion of deaths from multiple sclerosis (MS) among men in the armed forces. AIMS: To document and explore possible explanations for the observed excess. METHODS: We analysed data on underlying cause of death and last full-time occupation for 3,688,916 deaths among men aged 20-74 years in England and Wales during 1979-2010, calculating proportional mortality ratios (PMRs) standardised for age. We compared PMRs for MS in the armed forces with those for each main social class, and in selected other occupations. We also compared PMRs for MS with those for motor neurone disease (MND). RESULTS: The overall PMR for MS in the armed forces during 1979-2010 was 243 (95%CI 203-288). The excess was apparent in each of three separate decades of study (PMRs, ranging from 220 to 259), and across the entire age range. PMRs for MS were not elevated to the same extent in comparator occupations, nor in any of the main social classes. There was no parallel increase in PMRs for MND. CONCLUSIONS: These findings suggest that the high proportional mortality from MS in British military personnel is unlikely to have occurred by chance, or as an artefact of the method of investigation. However, the only military cohort study with published results on MS does not support an increased risk. It would be useful to analyse data on MS from other established military cohorts, to check for evidence of a hazard.

Trends in mortality from occupational hazards among men in England and Wales during 1979-2010.

OBJECTIVES: To monitor the impact of health and safety provisions and inform future preventive strategies, we investigated trends in mortality from established occupational hazards in England and Wales. METHODS: We analysed data from death certificates on underlying cause of death and last full-time occupation for 3 688 916 deaths among men aged 20-74 years in England and Wales during 1979-2010 (excluding 1981 when records were incomplete). Proportional mortality ratios (PMRs), standardised for age and social class, were calculated for occupations at risk of specified hazards. Observed and expected numbers of deaths for each hazard were summed across occupations, and the differences summarised as average annual excesses. RESULTS: Excess mortality declined substantially for most hazards. For example, the annual excess of deaths from chronic bronchitis and emphysema fell from 170.7 during 1979-1990 to 36.0 in 2001-2010, and that for deaths from injury and poisoning from 237.0 to 87.5. In many cases, the improvements were associated with falling PMRs (suggesting safer working practices), but they also reflected reductions in the numbers of men employed in more hazardous jobs, and declining mortality from some diseases across the whole population. Notable exceptions to the general improvement were diseases caused by asbestos, especially in some construction trades and sinonasal cancer in woodworkers. CONCLUSIONS: The highest priority for future prevention of work-related fatalities is the minority of occupational disorders for which excess mortality remains static or is increasing, in particular asbestos-related disease among certain occupations in the construction industry and sinonasal cancer in woodworkers.

Job dissatisfaction and the older worker: baseline findings from the Health and Employment After Fifty study.

OBJECTIVES: Demographic changes are requiring people to work longer. Labour force participation might be promoted by tackling sources of job dissatisfaction. We aimed to describe the epidemiology of job dissatisfaction in older British workers, to explore which perceptions of work contribute most importantly, and to assess possible impacts on health. METHODS: Participants aged 50-64 years were recruited from 24 English general practices. At baseline, those currently in work (N=5437) reported on their demographic and employment circumstances, overall job satisfaction, perceptions of their work that might contribute to dissatisfaction, and their general health, mood and well-being. Associations of job dissatisfaction with risk factors and potential health outcomes were assessed cross-sectionally by logistic regression, and the potential contributions of different negative perceptions to overall dissatisfaction were summarised by population attributable fractions (PAFs). RESULTS: Job dissatisfaction was more common among men, below age 60 years, those living in London and the South East, in the more educated and in those working for larger employers. The main contributors to job dissatisfaction among employees were feeling unappreciated and/or lacking a sense of achievement (PAF 55-56%), while in the self-employed, job insecurity was the leading contributor (PAF 79%). Job dissatisfaction was associated with all of the adverse health outcomes examined (ORs of 3-5), as were most of the negative perceptions of work that contributed to overall dissatisfaction. CONCLUSIONS: Employment policies aimed at improving job satisfaction in older workers may benefit from focussing particularly on relationships in the workplace, fairness, job security and instilling a sense of achievement.

Phenoxy herbicides, soft-tissue sarcoma and non-Hodgkin lymphoma: a systematic review of evidence from cohort and case-control studies.

BACKGROUND: Phenoxy herbicides have been used widely in agriculture, forestry, parks and domestic gardens. Early studies linked them with soft-tissue sarcoma (STS) and non-Hodgkin lymphoma (NHL), but when last reviewed by the International Agency for Research on Cancer in 1986, the evidence for human carcinogenicity was limited. SOURCES OF DATA: We searched Medline and Embase, looking for cohort or case-control studies that provided data on risk of STS and/or NHL in relation to phenoxy herbicides, and checked the reference lists of relevant publications for papers that had been missed. AREAS OF AGREEMENT, AREAS OF CONTROVERSY: The extensive evidence is not entirely consistent, and a hazard of STS or NHL cannot firmly be ruled out. However, if there is a hazard, then absolute risks must be small. GROWING POINTS, AREAS TIMELY FOR DEVELOPING RESEARCH: Extended follow-up of previously assembled cohorts may be the most efficient way of further reducing uncertainties.

Risk of cancer in workers exposed to styrene at eight British companies making glass-reinforced plastics.

OBJECTIVES: To provide further information on the risks of lymphohaematopoietic (LH) and other cancers associated with styrene. METHODS: We extended follow-up to December 2012 for 7970 workers at eight companies in England which used styrene in the manufacture of glass-reinforced plastics. Mortality was compared with that for England and Wales by the person-years method, and summarised by SMRs with 95% CIs. A supplementary nested case-control analysis compared styrene exposures, lagged by 5 years, in 122 incident or fatal cases of LH cancer and 1138 matched controls. RESULTS: A total of 3121 cohort members had died (2022 since the last follow-up). No elevation of mortality was observed for LH cancer, either in the full cohort (62 deaths, SMR 0.90, 95% CI 0.69 to 1.15), or in those with more than background exposure to styrene (38 deaths, SMR 0.82, 95% CI 0.58 to 1.14). Nor did the case-control analysis suggest any association with LH cancer. In comparison with background exposure, the OR for non-Hodgkin's lymphoma/chronic lymphocytic leukaemia in workers with high exposure (estimated 8-h time-weighted average of 40-100 ppm) for ≥1 year was 0.54 (95% CI 0.23 to 1.27). Mortality from lung cancer was significantly elevated, and risk increased progressively across exposure categories, with an SMR of 1.44 (95% CI 1.10 to 1.86) in workers highly exposed for ≥1 year. CONCLUSIONS: We found no evidence that styrene causes LH cancer. An association with lung cancer is not consistently supported by other studies. It may have been confounded by smoking, but would be worth checking further.

Sensory impairments, problems of balance and accidental injury at work: a case-control study.

OBJECTIVES: Sensory impairments are becoming increasingly common in the workforces of Western countries. To assess their role in occupational injury, and that of disorders of balance, we undertook a case-control study. METHODS: Using the Clinical Practice Research Datalink, which documents all medical consultations, referrals and diagnoses in primary care for 6% of the British population, we identified 1348 working-aged patients who had consulted medical services over a 22-year period for workplace injury (cases) and 6652 age-matched, sex-matched and practice-matched controls. Risks were assessed by conditional logistic regression, for earlier recorded diagnoses of visual impairment, common eye diseases, hearing loss, perforated ear drum, non-acute otitis media and disorders of balance. RESULTS: In all, 173 (2.2%) participants had an earlier eye problem, 792 (9.9%) an ear problem (including 336 with impaired hearing and 482 with non-acute otitis media) and 266 (3.3%) a disorder of balance. No associations were found with glaucoma, cataract, retinal disorders or perforation of the ear drum specifically, but adjusted ORs were moderately elevated for eye and ear problems more generally, and higher where there was a record of blindness or partial sight (OR 1.90, 95% CI 1.05 to 3.44) or non-acute otitis media (OR 2.04, 95% CI 1.64 to 2.54). Risks for non-acute otitis media and for disorders of balance were particularly elevated for consultations in the 12 months preceding injury consultation (OR 2.70, 95% CI 1.58 to 4.62 and 1.77, 95% CI 1.01 to 3.11, respectively). CONCLUSIONS: Problems of vision, impairments of hearing and disorders of balance all may carry moderately increased risks of occupational injury.

Soft tissue sarcoma, non-Hodgkin's lymphoma and chronic lymphocytic leukaemia in workers exposed to phenoxy herbicides: extended follow-up of a UK cohort.

OBJECTIVES: To provide further information on the possible carcinogenicity of phenoxy herbicides, and in particular their relationship to soft tissue sarcoma (STS), non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukaemia (CLL). METHODS: We extended follow-up to December 2012 for 8036 men employed at five factories in the UK which had manufactured phenoxy herbicides, or in a contract spraying business. Mortality was compared with that for England and Wales by the person-years method. Nested case-control analyses compared men with incident or fatal STS (n=15) or NHL/CLL (n=74) and matched controls (up to 10 per case). RESULTS: 4093 men had died, including 2303 since the last follow-up. Mortality from all causes and all cancers was close to expectation, but an excess of deaths from NHL was observed among men who had worked for ≥1 year in jobs with more than background exposure to phenoxy herbicides (19 deaths, SMR 1.85, 95% CI 1.12 to 2.89). Four deaths from STS occurred among men potentially exposed above background (3.3 expected). In the nested case-control analyses, there were no significantly elevated risks or consistent trends across categories of potential exposure for either STS or NHL/CLL. Among men who had worked for ≥1 year in potentially exposed jobs, the highest OR (for STS) was only 1.30 (95% CI 0.30 to 5.62). CONCLUSIONS: Our findings are consistent with the current balance of epidemiological evidence. If phenoxy herbicides pose a hazard of either STS or NHL, then any absolute increase in risk is likely to be small.

Health and Employment after Fifty (HEAF): a new prospective cohort study.

BACKGROUND: Demographic trends in developed countries have prompted governmental policies aimed at extending working lives. However, working beyond the traditional retirement age may not be feasible for those with major health problems of ageing, and depending on occupational and personal circumstances, might be either good or bad for health. To address these uncertainties, we have initiated a new longitudinal study. METHODS/DESIGN: We recruited some 8000 adults aged 50-64 years from 24 British general practices contributing to the Clinical Practice Research Datalink (CPRD). Participants have completed questionnaires about their work and home circumstances at baseline, and will do so regularly over follow-up, initially for a 5-year period. With their permission, we will access their primary care health records via the CPRD. The inter-relation of changes in employment (with reasons) and changes in health (e.g., major new illnesses, new treatments, mortality) will be examined. DISCUSSION: CPRD linkage allows cost-effective frequent capture of detailed objective health data with which to examine the impact of health on work at older ages and of work on health. Findings will inform government policy and also the design of work for older people and the measures needed to support employment in later life, especially for those with health limitations.

Upper airway cancer, myeloid leukemia, and other cancers in a cohort of British chemical workers exposed to formaldehyde.

The International Agency for Research on Cancer controversially has classified formaldehyde as causing nasopharyngeal carcinoma and myeloid leukemia. To provide further information on this question, we extended follow-up of a cohort of 14,008 chemical workers at 6 factories in England and Wales, covering the period 1941-2012. Mortality was compared with national death rates for England and Wales, and associations with incident upper airway cancer and leukemia were explored in nested case-control analyses. We observed excess deaths from cancers of the esophagus (100 observed vs. 93.1 expected), stomach (182 vs. 141.4), rectum (107 vs. 86.8), liver (35 vs. 26.9), and lung (813 vs. 645.8), but none of these tumors exhibited a clear exposure-response relationship. Nested case-control analyses of 115 men with upper airway cancer (including 1 nasopharyngeal cancer), 92 men with leukemia, and 45 men with myeloid leukemia indicated no elevations of risk in the highest exposure category (high exposure for ≥1 year). When the 2 highest exposure categories were combined, the odds ratio for myeloid leukemia was 1.26 (95% confidence interval: 0.39, 4.08). Our results provide no support for an increased hazard of myeloid leukemia, nasopharyngeal carcinoma, or other upper airway tumors from formaldehyde exposure. These results indicate that any excess risk of these cancers, even from relatively high exposures, is at most small.

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 case's 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.

Work activities and risk of prematurity, low birth weight and pre-eclampsia: an updated review with meta-analysis.

OBJECTIVES: We assessed the evidence relating preterm delivery (PTD), low birth weight, 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 to 2011), updating a previous search with a further 6 years of observations. METHODS: As before, combinations of keywords and medical subject headings 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 (RR) in meta-analysis. RESULTS: Analysis was based on 86 reports (32 cohort investigations, 57 with usable data on PTD, 54 on birth weight 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 (eg, RR>1.2). Larger and higher quality studies were less positive, while meta-estimates of risk were smaller than in previous analyses 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. CONCLUSIONS: 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.

Differences in risk factors for neurophysiologically confirmed carpal tunnel syndrome and illness with similar symptoms but normal median nerve function: a case-control study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Impact of carpal tunnel surgery according to pre-operative abnormality of sensory conduction in median nerve: a longitudinal study.

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.