Return to work and employment retention after uni-compartmental and total knee replacement: findings from the Clinical Outcomes in Arthroplasty study.

BACKGROUND: Little is known about ability to work after unicompartmental knee replacement (UKR) and total knee replacement (TKR), especially in physically-demanding occupations. This study described rates of return-to-work (RTW) and ability to sustain work by job after arthroplasty. METHOD: Participants from The Clinical Outcomes in Arthroplasty Study (COASt) aged 18-65 were eligible if they underwent UKR or TKR and had at least 5 years' follow-up post-operation. We posted a survey asking about pre-operative occupation, post-operative occupations and associated physical demands, and whether they had quit a job post-surgery due to difficulties with the operated knee (knee-related job loss (KRJL)). We fitted Cox Proportional Hazard Models to investigate the role of demanding physical activities on KRJL. RESULTS: 251 people (143 UKR, 108 TKR) returned a questionnaire, of whom 101 UKR and 57 TKR worked post-operatively. Rates of RTW were highest amongst those in managerial and professional or technical roles, whichever operation they received. RTW was poorest amongst those in elementary occupations. In associate professional/technical occupations, RTW rates were better amongst UKR recipients. Amongst participants who returned to work, 17 reported KRJL (8.5% UKR and 16.7% TKR). Respondents were more likely to have KRJL if their job involved carrying/lifting ≥10 kg (HR:4.81, 95%CI 1.55-14.93) or climbing >30 flights of stairs (HR:4.03, 95%CI 1.36-11.98). CONCLUSIONS: Knee arthroplasty recipients working pre-operatively mostly RTW. RTW may be more difficult after TKR than UKR. Jobs which involve lifting and climbing stairs may be particularly challenging. Surgeons offering knee arthroplasty should counsel patients about workability as well as risk of revision.

Sickness absence after carpal tunnel release: a multicentre prospective cohort study.

OBJECTIVES: To describe when patients return to different types of work after elective carpal tunnel release (CTR) surgery and identify the factors associated with the duration of sickness absence. DESIGN: Multicentre prospective observational cohort study. SETTING AND PARTICIPANTS: Participants were recruited preoperatively from 16 UK centres and clinical, occupational and demographic information were collected. Participants completed a weekly diary and questionnaires at four and 12 weeks postoperatively. OUTCOMES: The main outcome was duration of work absence from date of surgery to date of first return to work. RESULTS: 254 participants were enrolled in the study and 201 provided the follow-up data. Median duration of sickness absence was 20 days (range 1-99). Earlier return to work was associated with having surgery in primary care and a self-reported work role involving more than 4 hours of daily computer use. Being female and entitlement to more than a month of paid sick leave were both associated with longer work absences. The duration of work absence was strongly associated with the expected duration of leave, as reported by participants before surgery. Earlier return to work was not associated with poorer clinical outcomes reported 12 weeks after CTR. CONCLUSIONS: There was wide variation in the duration of work absence after CTR across all occupational categories. A combination of occupational, demographic and clinical factors was associated with the duration of work absence, illustrating the complexity of return to work decision making. However, preoperative expectations were strongly associated with the actual duration of leave. We found no evidence that earlier return to work was harmful. Clear, consistent advice from clinicians preoperatively setting expectations of a prompt return to work could reduce unnecessary sickness absence after CTR. To enable this, clinicians need evidence-informed guidance about appropriate timescales for the safe return to different types of work.

Work participation and risk factors for health-related job loss among older workers in the Health and Employment after Fifty (HEAF) study: Evidence from a 2-year follow-up period.

INTRODUCTION: Rapidly increasing population old age dependency ratios create a growing economic imperative for people to work to older ages. However, rates of older worker employment are only increasing slowly. Amongst a cohort of contemporary older workers, we investigated risk factors for health-related job loss (HRJL) over 2 years of follow-up. METHODS: HEAF is a population based cohort study of adults in England (aged 50-64 years at baseline) who provided information about socio-demographic characteristics, lifestyle, and work at baseline and annual follow-ups. Exits from paid work were mapped and risk factors for HRJL explored in a multiple-record survival dataset by Cox proportional hazards models. RESULTS: 2475 (75%) men and 2668 (66%) women were employed; 115 (4.6%) men and 182 (6.8%) women reported HRJL. Employment as road transport drivers/in vehicle trades (men), or as teaching/education/nursing/midwifery professionals or in caring personal services (women), was more frequent among people exiting work for health-related versus non-health-related reasons. Principal socio-demographic and lifestyle risk factors for HRJL were: struggling financially (men and women); low physical activity (men); being overweight or obese, and current smoking (women). Mutually adjusted work-related risk factors for HRJL were job dissatisfaction, and not coping with the physical (hazard ratio [95% confidence interval]: men 5.34[3.40,8.39]; women 3.73[2.48,5.60]) or mental demands (women only, 2.02[1.38,2.96]) of work. CONCLUSIONS: Employment characteristics of contemporary older workers differ by sex. Job satisfaction and perceived ability to cope with the physical and mental demands of work are key determinants of HRJL which employers could potentially influence to enable work to older ages.

Levels and Determinants of Fine Particulate Matter and Carbon Monoxide in Kitchens Using Biomass and Non-Biomass Fuel for Cooking.

To assist interpretation of a study in rural Pakistan on the use of biomass for cooking and the risk of coronary heart disease, we continuously monitored airborne concentrations of fine particulate matter (PM2.5) and carbon monoxide (CO) for up to 48 h in the kitchens of households randomly selected from the parent study. Satisfactory data on PM2.5 and CO respectively were obtained for 16 and 17 households using biomass, and 19 and 17 using natural gas. Linear regression analysis indicated that in comparison with kitchens using natural gas, daily average PM2.5 concentrations were substantially higher in kitchens that used biomass in either a chimney stove (mean difference 611, 95% CI: 359, 863 µg/m3) or traditional three-stone stove (mean difference 389, 95% CI: 231, 548 µg/m3). Daily average concentrations of CO were significantly increased when biomass was used in a traditional stove (mean difference from natural gas 3.7, 95% CI: 0.8, 6.7 ppm), but not when it was used in a chimney stove (mean difference -0.8, 95% CI: -4.8, 3.2 ppm). Any impact of smoking by household members was smaller than that of using biomass, and not clearly discernible. In the population studied, cooking with biomass as compared with natural gas should serve as a good proxy for higher personal exposure to PM2.5.

Is radiographic lumbar spondylolisthesis associated with occupational exposures? Findings from a nested case control study within the Wakayama spine study.

BACKGROUND: To explore the relationship between radiographic spondylolisthesis and occupational factors in a case-control study nested within the Wakayama Spine Study (WSS). METHODS: The WSS is a cross-sectional observational study amongst Japanese adults. All participants completed a lifetime occupational history and underwent X-rays of the lumbar spine (L1-S1) according to a pre-defined protocol. One trained surgeon graded the presence of a spondylolisthesis based upon ≥5% anterior or posterior slip at one or more levels. Cases, with lumbar spondylolisthesis, were compared with controls without, for their principal occupation and occupational exposures. RESULTS: In total, data were available for 722 adults (245 men and 477 women), mean age 70.1 (range 53-93) years. According to the pre-defined radiographic criteria, 117 were defined with spondylolisthesis (cases), leaving 605 controls. Cases were not significantly different from controls for age, gender, BMI, smoking or alcohol intake. However, cases were more than twice as likely to report occupational driving ≥4 h/day (OR 2.39, 95% CI 1.08-5.27) after adjustment for age, gender and BMI. Additionally, after stratification by age using 75 years as a cut-point, cases were more than 3-fold more likely to report having worked in the agricultural/ fishing industries (OR 3.47, 95% CI 1.29-9.29) among those aged < 75 years. A reduced risk of being a case was associated with climbing slopes/steps and walking. CONCLUSIONS: A history of occupational driving and working in the agricultural/fishing industry were associated with radiographic spondylolisthesis in this cross-sectional population study. This finding requires further evaluation in longitudinal studies.

Factory and construction work is associated with an increased risk of severe lumbar spinal stenosis on MRI: A case control analysis within the wakayama spine study.

BACKGROUND: To explore the association of MRI-diagnosed severe lumbar spinal stenosis with occupation. METHODS: Occupational data were collected by questionnaire and all participants underwent spine MRI scans using the same protocol. Central lumbar spinal stenosis (LSS) was graded qualitatively. Those with severe LSS (>two-thirds narrowing) were compared with the controls with lesser degrees of stenosis or no stenosis. RESULTS: Data were available for 722 subjects, mean age 70.1 years. 239 (33%) cases with severe LSS were identified. Factory/construction workers had an almost four-fold increased risk of severe LSS after adjustment for age, sex, smoking, and walking speed amongst those aged <75 years (OR 3.97, 95%CI 1.46-10.85). Severe LSS was also associated with squatting ≥1 h/day (OR 1.76, 95%CI 1.01-3.07) but this association became non-significant after adjustment. CONCLUSION: Further research is needed but this study adds more evidence that occupational factors are associated with an increased risk and/or severity of degenerative disease of the lumbar spine.

Return to work recommendations after carpal tunnel release: a survey of UK hand surgeons and hand therapists.

There is a limited evidence base from which to derive recommendations for safe and effective return to different types of occupation after carpal tunnel release surgery. The current practice of members of the British Society for Surgery of the Hand and the British Association of Hand Therapists was investigated with a questionnaire. In total, 173 surgeons and 137 therapists responded from an estimated sample of 1959. Median recommended return-to-work times were 7 days for desk-based duties, 15 days for repetitive light manual duties and 30 days for heavy manual duties. However, the responses were wide-ranging: 0-30 days for desk-based; 1-56 days for repetitive light manual; and 1-90 days for heavy manual. Variation in the recommended timescales for return to work and other functional activities after carpal tunnel release suggests that patients are receiving different and possibly even conflicting advice. LEVEL OF EVIDENCE: V.

The relationship between dietary quality and the local food environment differs according to level of educational attainment: A cross-sectional study.

There is evidence that food outlet access differs according to level of neighbourhood deprivation but little is known about how individual circumstances affect associations between food outlet access and diet. This study explored the relationship between dietary quality and a measure of overall food environment, representing the balance between healthy and unhealthy food outlet access in individualised activity spaces. Furthermore, this study is the first to assess effect modification of level of educational attainment on this relationship. A total of 839 mothers with young children from Hampshire, United Kingdom (UK) completed a cross-sectional survey including a 20-item food frequency questionnaire to measure diet and questions about demographic characteristics and frequently visited locations including home, children's centre, general practitioner, work, main food shop and physical activity location. Dietary information was used to calculate a standardised dietary quality score for each mother. Individualised activity spaces were produced by creating a 1000m buffer around frequently visited locations using ArcGIS. Cross-sectional observational food outlet data were overlaid onto activity spaces to derive an overall food environment score for each mother. These scores represented the balance between healthy and unhealthy food outlets using weightings to characterise the proportion of healthy or unhealthy foods sold in each outlet type. Food outlet access was dominated by the presence of unhealthy food outlets; only 1% of mothers were exposed to a healthy overall food environment in their daily activities. Level of educational attainment moderated the relationship between overall food environment and diet (mid vs low, p = 0.06; high vs low, p = 0.04). Adjusted stratified linear regression analyses showed poorer food environments were associated with better dietary quality among mothers with degrees (ß = -0.02; 95%CI: -0.03, -0.001) and a tendency toward poorer dietary quality among mothers with low educational attainment, however this relationship was not statistically significant (ß = 0.01; 95%CI: -0.01, 0.02). This study showed that unhealthy food outlets, like takeaways and convenience stores, dominated mothers' food outlet access, and provides some empirical evidence to support the concept that individual characteristics, particularly educational attainment, are protective against exposure to unhealthy food environments. Improvements to the imbalance of healthy and unhealthy food outlets through planning restrictions could be important to reduce dietary inequalities.

Getting started with tables.

BACKGROUND: Tables are often overlooked by many readers of papers who tend to focus on the text. Good tables tell much of the story of a paper and give a richer insight into the details of the study participants and the main research findings. Being confident in reading tables and constructing clear tables are important skills for researchers to master. METHOD: Common forms of tables were considered, along with the standard statistics used in them. Papers in the Archives of Public Health published during 2015 and 2016 were hand-searched for examples to illustrate the points being made. Presentation of graphs and figures were not considered as they are outside the scope of the paper. RESULTS: Basic statistical concepts are outlined to aid understanding of each of the tables presented. The first table in many papers gives an overview of the study population and its characteristics, usually giving numbers and percentages of the study population in different categories (e.g. by sex, educational attainment, smoking status) and summaries of measured characteristics (continuous variables) of the participants (e.g. age, height, body mass index). Tables giving the results of the analyses follow; these often include summaries of characteristics in different groups of participants, as well as relationships between the outcome under study and the exposure of interest. For continuous outcome data, results are often expressed as differences between means, or regression or correlation coefficients. Ratio/relative measures (e.g. relative risks, odds ratios) are usually used for binary outcome measures that take one of two values for each study participants (e.g. dead versus alive, obese versus non-obese). Tables come in many forms, but various standard types are described here. CONCLUSION: Clear tables provide much of the important detail in a paper and researchers are encouraged to read and construct them with care.

Education and the Relationship Between Supermarket Environment and Diet.

INTRODUCTION: Supermarkets are a major source of food for many families. Knowledge of how educational attainment affects the relationship between in-store environments of supermarkets and diet is needed. This study examined the relationship between maternal dietary quality and overall in-store supermarket environment, and assessed the effect modification of educational attainment. METHODS: Dietary quality z-scores were calculated for 829 mothers with young children using cross-sectional data collected in 2010-2011 from a 20-item food frequency questionnaire. Information about nine in-store factors (variety, price, quality, promotion, shelf placement, store placement, nutrition information, healthier alternatives, and single fruit sale) on 12 foods known to discriminate between better and poorer dietary quality were collected to create a standardized "healthfulness" z-score for each supermarket where mothers shopped. RESULTS: Multilevel unadjusted linear regression analysis completed in 2014-2015 showed that shopping at more-healthful supermarkets was associated with better dietary quality (ß=0.39 SD/SD, p=0.01, 95% CI=0.10, 0.68). However, the relationship differed according to educational attainment (interaction, p=0.006). Among mothers who left school at age 16 years, those who shopped at less healthful supermarkets had poorer dietary quality (ß=0.31 SD/SD, 95% CI=0.07, 0.55). Among mothers with degrees, those who shopped at less healthful supermarkets had better dietary quality (ß=-0.59 SD/SD, 95% CI=-1.19, 0.00). CONCLUSIONS: Mothers with low educational attainment show greater susceptibility to less healthful in-store environments than mothers with higher educational attainment who may be protected by greater psychological and financial resources. Policy initiatives to improve supermarket environments may be necessary to address dietary inequalities.

Descriptive Epidemiology of Somatising Tendency: Findings from the CUPID Study.

Somatising tendency, defined as a predisposition to worry about common somatic symptoms, is importantly associated with various aspects of health and health-related behaviour, including musculoskeletal pain and associated disability. To explore its epidemiological characteristics, and how it can be specified most efficiently, we analysed data from an international longitudinal study. A baseline questionnaire, which included questions from the Brief Symptom Inventory about seven common symptoms, was completed by 12,072 participants aged 20-59 from 46 occupational groups in 18 countries (response rate 70%). The seven symptoms were all mutually associated (odds ratios for pairwise associations 3.4 to 9.3), and each contributed to a measure of somatising tendency that exhibited an exposure-response relationship both with multi-site pain (prevalence rate ratios up to six), and also with sickness absence for non-musculoskeletal reasons. In most participants, the level of somatising tendency was little changed when reassessed after a mean interval of 14 months (75% having a change of 0 or 1 in their symptom count), although the specific symptoms reported at follow-up often differed from those at baseline. Somatising tendency was more common in women than men, especially at older ages, and varied markedly across the 46 occupational groups studied, with higher rates in South and Central America. It was weakly associated with smoking, but not with level of education. Our study supports the use of questions from the Brief Symptom Inventory as a method for measuring somatising tendency, and suggests that in adults of working age, it is a fairly stable trait.

Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport.

INTRODUCTION: Maternal environment and lifestyle factors may modify placental function to match the mother's capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content) on a selection of metabolic and amino acid transporter genes and their associations with fetal growth. METHODS: RNA was extracted from 102 term Southampton Women's Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR. RESULTS: Increased placental LAT2 (p = 0.01), y+LAT2 (p = 0.03), aspartate aminotransferase 2 (p = 0.02) and decreased aspartate aminotransferase 1 (p = 0.04) mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01), ASCT1 (p = 0.03), mitochondrial branched chain aminotransferase (p = 0.02) and glutamine synthetase (p = 0.05) was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05) associated with higher maternal diet quality (prudent dietary pattern) pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05) and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01) associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01). Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001). CONCLUSION: A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of transporter and metabolic genes and maternal smoking, physical activity and diet raises the possibility that their effects are mediated in part through alterations in placental function. The observed changes in placental gene expression in relation to modifiable maternal factors are important as they could form part of interventions aimed at maintaining a healthy lifestyle for the mother and for optimal fetal development.

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.

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.

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.

Processed meat consumption and lung function: modification by antioxidants and smoking.

Unhealthy dietary patterns are associated with poor lung function. It is not known whether this is due to low consumption of antioxidant-rich fruit and vegetables, or is a consequence of higher intakes of harmful dietary constituents, such as processed meat. We examined the individual and combined associations of processed meat, fruit and vegetable consumption and dietary total antioxidant capacity (TAC) with lung function among 1551 males and 1391 females in the UK in the Hertfordshire Cohort Study. Diet was assessed using a food frequency questionnaire. After controlling for confounders, processed meat consumption was negatively associated with forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio in males and females, while fruit and vegetable consumption and dietary TAC were positively associated with FEV1 and FVC, but not FEV1/FVC ratio. In males, the negative association between processed meat consumption and FEV1 was more marked in those who had low fruit and vegetable consumption (p=0.035 for interaction), and low dietary TAC (p=0.025 for interaction). The deficit in FEV1/FVC associated with processed meat consumption was larger in males who smoked (p=0.022 for interaction). Higher processed meat consumption is associated with poorer lung function, especially in males who have lower fruit and vegetable consumption or dietary TAC, and among current smokers.

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.

Symptoms, signs and nerve conduction velocities in patients with suspected carpal tunnel syndrome.

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

Psychological and culturally-influenced risk factors for the incidence and persistence of low back pain and associated disability in Spanish workers: findings from the CUPID study.

OBJECTIVE: To assess the importance of psychological and culturally-influenced factors as predictors of low back pain (LBP) incidence and persistence in Spanish workers. METHODS: As part of the international Cultural and Psychosocial Influences in Disability (CUPID) study, 1105 Spanish nurses and office workers answered questions at baseline about LBP in the past month and past year, associated disability, occupational lifting, smoking habits, health beliefs, mental health, and distress from common somatic symptoms. At 12-month follow-up, they were asked about LBP and associated disability in the past month. Associations with LBP incidence and persistence were assessed by log binomial regression, and characterised by prevalence rate ratios (PRRs) with associated 95% CIs. RESULTS: 971 participants (87.9%) completed follow-up. Among 579 with no LBP at baseline, 22.8% reported LBP at follow-up. After adjustment for sex, age and occupation, new LBP was predicted by poor mental health (PRR 1.5, 95% CI 1.0 to 2.2), somatising tendency (PRR 1.8, 95% CI 1.2 to 2.7) and presence of LBP for >1 month in the year before baseline (PRR 4.7, 95% CI 3.1 to 6.9). Among 392 subjects who had LBP at baseline, 59.4% reported persistence at follow-up, which was associated with presence of symptoms for >1 month in the 12 months before baseline (PRR 1.4, 95% CI 1.2 to 1.7) and more weakly with somatising tendency, and with adverse beliefs about LBP work-relatedness and prognosis. CONCLUSIONS: In Spain, as in northern European countries, psychological and culturally-influenced factors have an important role in LBP development and persistence.