Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study.

BACKGROUND: Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS). METHODS: Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression. RESULTS: Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration. CONCLUSIONS: In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors.

Predicting work-related incidence of lateral and medial epicondylitis using the strain index.

BACKGROUND: The Strain Index (SI) has been developed to evaluate the risk for developing a distal upper extremity disorder. The objective of this study is to determine if the SI predicts incidence cases of work-related lateral, medial, or any epicondylities (LEPI, MEPI, and EPI). METHODS: Six hundred seven workers were followed for up to 3.5 years, 70 developed EPI on the dominant side (44 LEPI, 13 MEPI, and 13 both). Survival analyses were conducted adjusting for demographic, psychosocial, and work organizational factors, with the SI as time-dependent variable. RESULTS: High exposure (SI > 5), older age, and self-perceived poor general health were associated with incidence of LEPI and EPI, but not MEPI. There was a significant relationship between higher scores of SI and LEPI, hazard ratio (HR) 2.00 (95% CI 1.04-3.87) for SI 5.1-12, HR 2.12 (95% CI 1.11-4.05) for SI > 12. CONCLUSIONS: The SI can effectively identify jobs with increased risk of developing incidence of LEPI.

The association between combination of hand force and forearm posture and incidence of lateral epicondylitis in a working population.

OBJECTIVE: The objective of this prospective study is to investigate the exposure-response relationships between various workplace physical exposures of force, repetition, and their combination assessed at an individual level with lateral epicondylitis (LE). BACKGROUND: Workplace upper extremity musculoskeletal disorders (UEMSDs) are prevalent, disabling, and expensive. LE is one of the major UEMSDs in active workers. METHOD: We used detailed health history, symptoms, and physical examination for identifying incidence and detailed exposure assessment to capture work tasks of each worker and to measure quantitative mechanical workload. We used counting process style input of proportional hazards regression for modeling cumulative incidence that accounts for changed exposure estimates during the follow-up period when respondents change jobs. RESULTS: The incidence rate of LE on the dominant side was 4.91 per 100 person-years. Adjusted for age and gender, the combined effect of forearm pronation > or = 45 degrees for > or = 40% of time and time spent with forceful exertion, including any power grip (hazard ratio [HR] = 2.8, 95% confidence interval [CI] = [1.35-5.77]), lifting for > or = 3% of time (HR = 2.50, 95% CI = [1.19-5.24]), and duty cycle for forceful exertion for > or = 10% (HR = 2.25, 95% CI = [1.09-4.66]), were significant predictors of dominant side LE, whereas neither the awkward posture nor the forceful exertion alone was significant. Older workers with jobs requiring a high percentage of time working with force in combination with awkward postures of forearm were more likely to predict LE. CONCLUSION: This study shows the evidence of the etiologic role of strenuous manual tasks in the occurrence of LE.

Obesity prevalence by occupation in Washington State, Behavioral Risk Factor Surveillance System.

INTRODUCTION: Data that estimate the prevalence of and risk factors for worker obesity by occupation are generally unavailable and could inform the prioritization of workplace wellness programs. The aims of this study were to estimate the prevalence of obesity by occupation, examine the association of occupational physical activity and a range of health behaviors with obesity, and identify occupations in which workers are at high risk of obesity in Washington State. METHODS: We conducted descriptive and multivariable analyses among 37,626 employed Washington State respondents using the Behavioral Risk Factor Surveillance System in odd numbered years, from 2003 through 2009. We estimated prevalence and prevalence ratios (PRs) by occupational groups adjusting for demographics, occupational physical activity level, smoking, fruit and vegetable consumption, and leisure-time physical activity (LPTA). RESULTS: Overall obesity prevalence was 24.6% (95% confidence interval [CI], 24.0-25.1). Workers in protective services were 2.46 (95% CI, 1.72-3.50) times as likely to be obese as workers in health diagnosing occupations. Compared with their counterparts, workers who consumed adequate amounts of fruits and vegetables and had adequate LTPA were significantly less likely to be obese (PR = 0.91; 95% CI, 0.86-0.97 and PR = 0.63; 95% CI, 0.60-0.67, respectively). Workers with physically demanding occupational physical activity had a lower PR of obesity (PR = 0.83; 95% CI, 0.78-0.88) than those with nonphysically demanding occupational physical activity. CONCLUSION: Obesity prevalence and health risk behaviors vary substantially by occupation. Employers, policy makers, and health promotion practitioners can use our results to target and prioritize workplace obesity prevention and health behavior promotion programs.

Effects of residential location and work-commuting on long-term work disability.

PURPOSE: Little is known about the independent effect of workers' residential location and work-commuting on their long-term disability due to work-related injuries. We examined 149,110 incident claims while adjusting for multiple risk factors in a large, population-based sample of Washington State workers' compensation State Fund claims during 2002-2008. METHODS: Claimants' residential addresses were geocoded with census tract and aggregated into four category classification of the Rural Urban Commuting Area Codes (RUCAs) which takes into account for tract-level work-commuting. We used logistic regressions to assess the association between RUCAs and whether or not a person was off work for more than 180 days due to injury; Quantile regressions to predict various percentiles of cumulative lost workdays by RUCAs. RESULTS: Compared to those who live in the Urban Core, workers in other areas experienced longer average paid time loss days due to work-related injury. The association between residential location and long-term disability was significant, odds ratio (OR) 1.19 (95 % confidence interval (CI) 1.11-1.27) for residents of Small Town and Isolated Rural and OR 1.17 (95 % CI 1.12-1.22) for those of Sub Urban, and persisted after controlling for injury nature, socio-demographic, employment-related, and claim administrative characteristics. The impact of residential location and work-commuting elevated as the duration of disability increased. CONCLUSIONS: This study shows that residential location and work-commuting has a significant and time-varying impact on duration of work disability. Workers living in Sub Urban and Small Town and Isolated Rural areas represent a particularly vulnerable group with respect to risk of long-term work disability.

Distribution of influenza-like illness (ILI) by occupation in Washington State, September 2009-August 2010.

OBJECTIVES: We aim to estimate the prevalence of influenza-like illness (ILI) by occupation and to identify occupations associated with increased ILI prevalence. METHODS: Between September 2009 and August 2010, the Centers for Disease Control (CDC) included questions on ILI symptoms on the Behavioral Risk Factor Surveillance System (BRFSS). Washington State collects the occupation of all employed BRFSS respondents. ILI prevalence and prevalence ratios (PR) were calculated by occupational group. RESULTS: There were 8,758 adult, currently employed, non-military respondents to the Washington BRFSS during the study period. The ILI prevalence for all employed respondents was 6.8% (95% Confidence Interval (95% CI) = 6.1, 7.6). PRs indicated a lower prevalence of ILI in Technicians (PR = 0.4, 95% CI = 0.2, 0.9) and Truck Drivers (PR = 0.2, 95% CI = 0.1, 0.7) and higher prevalence in Janitors and Cleaners (PR = 2.5, 95% CI = 1.3, 4.7) and Secretaries (PR = 2.4, 95% CI = 1.1, 5.4). CONCLUSIONS: Some occupations appear to have higher prevalence of ILI than others. These occupational differences may be explained, in part, by differing levels of social contact with the public or contact with contaminated surfaces at work, or by other occupational factors such as stress or access to health care resources.

Occupation and the prevalence of current depression and frequent mental distress, WA BRFSS 2006 and 2008.

BACKGROUND: Workers with depression and frequent mental distress (FMD) have lost work productivity. Limited systematic comparisons exist for the prevalence of depression and FMD across occupational groups. METHODS: Using a state-added question for occupation coupled to measures of depression and FMD on the Washington State (WA) 2006 and 2008 Behavioral Risk Factor Surveillance System survey, we estimated the prevalence and odds ratios (ORs) among the 20,560 WA workers. RESULTS: The prevalences of current depression and FMD were 5.2% and 7.5%, respectively. The prevalence varied considerably across occupations. Compared with Management occupation, Truck drivers had significantly increased odds for both current depression [OR = 6.18, 95% confidence interval (CI): 2.52-15.16] and FMD (OR = 1.85, 95% CI: 1.01-3.41). Cleaning/Building services (OR = 1.95, 95% CI: 1.11-3.40) and Protective services (OR = 1.97, 95% CI: 1.19-3.27) were associated with increased FMD. CONCLUSIONS: These findings demonstrate the need for research on possible sources of the differences for current depression and FMD across occupations.

The impact of regulatory enforcement and consultation visits on workers' compensation claims incidence rates and costs, 1999-2008.

BACKGROUND: Studies of regulatory effectiveness have shown mixed evidence of impact of inspections on injury rates. We examine changes in workers compensation claims rates and costs for Washington employers having either an inspection, with or without citation, or a voluntary consultation activity. METHOD: We merge 10 years of enforcement and consultation activity with workers compensation records at the individual workplace level for stable firms with a single business location and at least 10 full-time employees. The change in claims incidence rates (CIRs) was estimated, controlling for workplace claims rate history, size, and industry. Separate analyses were performed for non-musculoskeletal and musculoskeletal (MSD) CIRs, claims costs and for enforcement activities with citation and without citation. RESULTS: Enforcement activities are associated with a significant reduction in CIRs and costs. Similar results may also be attributable to consultations. Inspections were associated with a 4% decline in time-loss claims rates relative to uninspected workplaces. The effect strengthens when MSD claims are excluded. Citations for non-compliance are associated with a 20% decline in non-MSD CIRs relative to uninspected workplaces. There is also some evidence for a reduction in MSD claims rates beginning in the second year following inspection. Enforcement and consultation activity is associated with substantial decreases in claims costs. CONCLUSIONS: Enforcement activities make a significant contribution to reducing CIRs and costs. Similar results following consultations may also exist. Inspections with citations are more effective than those without. Claims rates for non-MSD injuries, related to hazards covered by specific standards, are more affected in the year following the visit, while those for MSDs take longer to begin falling.

The persistent gap in health-care coverage between low- and high-income workers in Washington State: BRFSS, 2003-2007.

OBJECTIVES: We examined the disparities in health-care coverage between low- and high-income workers in Washington State (WA) to provide support for possible policy decisions for uninsured workers. METHODS: We examined data from the WA Behavioral Risk Factor Surveillance System 2003-2007 and compared workers aged 18-64 years of low income (annual household income <$35,000) and high income (annual household income ≥$35,000) on proportions and sources of health-care coverage. We conducted multivariable logistic regression analyses on factors that were associated with the uninsured. RESULTS: Of the 54,536 survey respondents who were working-age adults in WA, 13,922 (25.5%) were low-income workers. The proportions of uninsured were 38.2% for low-income workers and 6.3% for high-income workers. While employment-based health benefits remained a dominant source of health insurance coverage, they covered only 40.2% of low-income workers relative to 81.5% of high-income workers. Besides income, workers were more likely to be uninsured if they were younger; male; Hispanic; less educated; not married; current smokers; self-employed; or employed in agriculture/forestry/fisheries, construction, and retail. More low-income workers (28.7%) reported cost as an issue in paying for health services than did their high-income counterparts (6.7%). CONCLUSION: A persistent gap in health-care coverage exists between low- and high-income workers. The identified characteristics of these workers can be used to implement policies to expand health insurance coverage.

Responsiveness of the QuickDASH and SF-12 in workers with neck or upper extremity musculoskeletal disorders: one-year follow-up.

INTRODUCTION Questionnaires that measure functional status such as the Disability of the Arm, Shoulder and Hand (QuickDASH) and the Medical Outcomes Study 12-item Short-Form Health Survey (SF-12) can quantify the impact of health on performance. Little is known about whether these questionnaires can be used as a tool for measuring disabilities among workers. We compare the responsiveness of these two functional status questionnaires to changes in clinical outcomes of neck or upper extremity musculoskeletal disorders (UEMSD) among active workers in a longitudinal study. METHODS We evaluated the effect size (ES) and standardized response means (SRM) of the QuickDASH and the SF-12 for 148 workers who were divided into four subgroups based on the diagnosis status change between baseline and 1-year visit. RESULTS The ES and SRM for QuickDASH scores were 0.6/0.6 for the 50 subjects who became incident symptomatic neck or UEMSD cases, 1.3/1.0 for the 18 subjects who became incident clinical cases of neck or UEMSD, -1.0/-1.1 for the 46 subjects who recovered from having neck or UEMSD symptoms, and -1.1/-1.1 for the 34 subjects who recovered from being neck or UEMSD clinical cases. The correspondent ES/SRM for the QuickDASH work module were 0.4/0.3, 0.7/0.5, -0.6/-0.4, and -1.0/-0.8, respectively. The correspondent ES/SRM for the physical component scores of SF-12 (PCS12) for the four subgroups were 0.2/0.2, -0.9/-0.6, 0.3/0.2, and 0.3/0.3, respectively. CONCLUSIONS The QuickDASH scores were responsive to changes among active workers who were neck or UEMSD symptomatic or clinical case. PCS12 scores were sufficient only for use in clinical case status change.

The natural course of carpal tunnel syndrome in a working population.

OBJECTIVE: The aim of this study was to assess prevalence, incidence, and persistence of carpal tunnel syndrome (CTS) and associated symptoms over a one-year period in a working population. METHODS: We conducted a one-year prospective study of 418 active workers in 12 worksites. Detailed health interviews, psychosocial questionnaires, and electrophysiological studies [ie, nerve conduction velocity (NCV) tests] were conducted at baseline and one-year follow-up. Individual-observed exposure assessments of wrist posture, hand activity, and hand forces were conducted. RESULTS: Prevalence of CTS cases at baseline was 10.8% [95% confidence interval (95% CI) 7.8-13.7%] on the dominant side and 6.0% (95% CI 3.7-87.3%) on the non-dominant side; CTS symptoms were 14.1% (95% CI 10.8-17.5%) and 11.0% (95% CI 8.0-14.0%), respectively. Incidence of CTS cases were 7.5% (95% CI 4.8-10.2%) and 5.6% (95% CI 3.3-7.9%), respectively. Higher proportions of subjects with current symptoms or positive electrophysiological test findings at baseline became CTS cases at one year compared to those with neither (28.6% and 13.9%, respectively, versus 0.5%). One-year persistence of CTS case status was 44.4% (95% CI 29.9-59.0%) for the dominant hand and 52.0% (95% CI 32.4-71.6) for non-dominant hand. There were significant differences at baseline between asymptomatic subjects and CTS cases with respect to higher job demands (P=0.027), lower job satisfaction (P=0.036), lower general health (P=0.0009), higher exposure to vibrating hand tool use (P=0.039), and greater time using a forceful power grip (P=0.035) among cases. CONCLUSIONS: CTS symptoms more than positive NCV test results alone appear to predict CTS at one year. Persistence of CTS at one year is high.

Language preference and non-traumatic low back disorders in Washington State workers' compensation.

BACKGROUND: Workers in the United States with limited English proficiency likely perform more hazardous work, experience higher rates of work-related injury and illness, and have worse disability outcomes. METHODS: We conducted a descriptive study of employment characteristics, timeliness and utilization of workers' compensation (WC) insurance benefits, cost and occupational health outcomes for Washington State WC state fund, non-traumatic low back disorders (LBD) claimants by language preference. RESULTS: A greater proportion of Spanish language preferring (SLP) LBD claims filed were accepted and resulted in lost work time than English language preferring (ELP) LBD claims. There were significant differences in the demographic, employment, and occupational characteristics between the SLP and ELP compensable claimant populations. The SLP LBD compensable claimants had greater time loss duration, greater medical and total claim costs, more use of physical therapy and vocational services than the ELP LBD compensable claimants. With the exception of the timeliness for providing the first time loss payment, the time periods for provision of insurance benefits did not differ between the SLP and ELP populations. SLP compensable claimants received less back surgery and had comparable permanent partial disability payments to the ELP population. Employers were more likely to protest the acceptance of a SLP compensable than one in an ELP LBD compensable claim. CONCLUSION: For those injured workers accessing the Washington State WC system, we observed differences based on language preference for pre-injury, and workers compensation outcomes. Further research is needed to explain the observed differences.

Temporary workers in Washington state.

BACKGROUND: Evidence regarding the unequal burden of occupational injuries between workers employed by temporary agencies and those in standard employment arrangements is unclear. Studies range from no significant differences in risk to substantial increased risk for temporary workers. The purpose of this study is to compare the workers' compensation experience of a large cohort of temporary agency employed workers with those in standard forms of employment. METHODS: Washington State Fund workers' compensation data were obtained for claims with injury dates from January 1, 2003 to June 30, 2006, resulting in 342,540 accepted claims. General descriptive statistics, injury rates (per 10,000 FTE), and rate ratios (temp agency/standard employer) were computed by injury type and industry. RESULTS: Temporary agency employed workers had higher rates of injury for all injury types, and higher median time loss (40 vs. 27 days) but lower time loss costs (median $1,224 vs. $1,914, P < 0.001) and lower medical costs ($3,026 vs. $4,087, P < 0.001) than standard arrangement workers. Temporary agency workers had substantially higher rates for "caught in" and "struck by" injuries in the construction (IRR 4.93; 95% CI 2.80-8.08) and manufacturing (IRR 4.05; 95% CI 3.25, 5.00) industry sectors. CONCLUSION: Temporary agency employed workers have higher claims incidence rates than those in standard employment arrangements. The rate ratios are twofold higher in the construction and manufacturing industry sectors. More research is needed to explore potential reasons for this disparity in occupational injuries. Industry or some measure of job exposure should be included when comparing injury rates in different types of employment in order to better identify areas for prevention.

Quantitative exposure-response relations between physical workload and prevalence of lateral epicondylitis in a working population.

BACKGROUND: Lateral epicondylitis is a common work-related musculoskeletal disorder. The objective of this study was to identify risk factors associated with lateral epicondylitis among active workers. METHODS: Seven-hundred thirty-three workers in 12 Washington worksites participated in structured interviews, physical examinations, and individual exposure assessments of biomechanical and psychosocial factors. Multivariable logistic modeling was used. RESULTS: Thirty-eight subjects (5.2%) had lateral epicondylitis. Age (36-50 years-old), being female, and low social support at work were significant risk factors. Frequency of forceful exertion (> or =5 vs. < 1 times/min (OR 5.17, 95%CI 1.78-15.02), and > or =1 to <5 vs. <1 (OR 4.47, 95%CI 1.57-13.71)) and forearm supination at > or =45 degrees for > or =5% of the time with high lifting force (OR = 2.98, 95% CI 1.18-7.55) were significant physical load factors. CONCLUSIONS: Frequency of forceful exertion or a combination of forearm supination and forceful lifting were significant physical factors and should be considered for prevention strategies.

Gender adjustment or stratification in discerning upper extremity musculoskeletal disorder risk?

OBJECTIVES: The aim was to explore whether "adjustment" for gender masks important exposure differences between men and women in a study of rotator cuff syndrome (RCS) and carpal tunnel syndrome (CTS) and work exposures. METHODS: This cross-sectional study of 733 subjects in 12 health care and manufacturing workplaces used detailed individual health and work exposure assessment methods. Multiple logistic regression analysis was used to compare gender stratified and adjusted models. RESULTS: Prevalence of RCS and CTS among women was 7.1% and 11.3% respectively, and among men 7.8% and 6.4%. In adjusted (gender, age, body mass index) multivariate analyses of RCS and CTS, gender was not statistically significantly different. For RCS, upper arm flexion >/=45 degrees and forceful pinch increased the odds in the gender-adjusted model (OR 2.66, 95% CI 1.26-5.59) but primarily among women in the stratified analysis (OR 6.68, 95% CI 1.81-24.66 versus OR 1.45, 95% CI 0.53-4.00). For CTS, wrist radial/ulnar deviation >/=4% time and lifting >/=4.5kg >3% time, the adjusted OR was higher for women (OR 4.85, 95% CI 2.12-11.11) and in the gender stratified analyses, the odds were increased for both genders (women OR 5.18, 95% CI 1.70-15.81 and men OR 3.63, 95% CI 1.08-12.18). CONCLUSIONS: Gender differences in response to physical work exposures may reflect gender segregation in work and potential differences in pinch and lifting capacity. Reduction in these exposures may reduce prevalence of upper extremity disorders for all workers.

Psychosocial factors and shoulder symptom development among workers.

BACKGROUND: Shoulder injuries are a common cause of pain and discomfort. Many work-related factors have been associated with the onset of shoulder symptoms. The psychosocial concepts in the demand-control model have been studied in association with musculoskeletal symptoms but with heterogeneous findings. The purpose of this study was to assess the relationship between the psychosocial concepts of the demand-control model and the incidence of shoulder symptoms in a working population. METHODS: After following 424 subjects for approximately 1 year, 85 incident cases were identified from self-reported data. Cox proportional hazards modeling was used to assess the associations between shoulder symptoms and demand-control model quadrants. RESULTS: Cases were more likely to be female and report other upper extremity symptoms at baseline (P < 0.05). From the hazard models, being in either a passive or high strain job quadrant was associated with the incidence of shoulder symptoms. Hazard ratios were 2.17, 95% CI 1.02-4.66 and 2.19, 95% CI 1.08-4.42, respectively. CONCLUSIONS: Using self-reporting to determine demand-control quadrants was successful in identifying subjects at risk of developing work-related shoulder symptoms. Research is needed to determine if this relationship holds with clinically diagnosed shoulder and other upper extremity musculoskeletal disorders. This may be part of a simple tool for assessing risk of developing these UEMSDs.

Assessing validity of the QuickDASH and SF-12 as surveillance tools among workers with neck or upper extremity musculoskeletal disorders.

The purpose of this article was to assess validity of the regional Disabilities of Arm, Shoulder, and Hand (QuickDASH) and Short-Form 12 (SF-12) for surveillance purpose. We compared the predictive, discriminate, and concurrent validity of the QuickDASH and SF-12 among 231 workers with specific clinical diagnoses of neck or upper extremity musculoskeletal disorders (UEMSDs) and 175 workers with symptoms only. Compared to those with symptoms only, the odds of being any neck or UEMSD case were 1.45 (95% confidence interval [95% CI]: 1.24-1.70) and 0.66 (95% CI: 0.48-0.91) with every 10-point increase in QuickDASH disability and physical component scale (PCS-12) scores, respectively. The clinical cases had significantly higher QuickDASH disability (23.0 vs. 14.3, p<0.0001) and lower PCS-12 scores (44.8 vs. 47.3, p=0.0133) than those with symptom only. The QuickDASH disability scores were moderately correlated with the PCS-12 scores (rho=-0.40) among the clinical cases. Either QuickDASH or PCS-12 can be used as a simple surveillance tool in an active working population.

Evaluation of a symptom diagram for identifying carpal tunnel syndrome.

BACKGROUND: Hand symptom diagrams (HSDs) for rating the distribution of paraesthesias are proposed for use in epidemiological studies of carpal tunnel syndrome (CTS). AIM: To assess the validity of HSDs in a working population of manufacturing and service workers participating in a prospective study of musculoskeletal disorders. METHODS: Assessment of each subject involved completing a HSD, a heath assessment and electrodiagnostic studies (EDSs). HSDs were rated for CTS blinded to the health assessment and EDS results. The validity assessments of HSD used EDS as the sole confirmatory standard for CTS. RESULTS: A total of 733 subjects (65% of those eligible) participated in the study and 720 underwent EDSs. Dominant hand prevalence of a positive HSD and delayed nerve conduction studies in this working population was 9.2 per 100 workers. The sensitivity of a positive HSD for all workers was 0.28. By restricting the population to those workers with any current hand symptoms or to any worker with neuropathic hand symptoms, the sensitivities of HSD improved to 0.61 and 0.79, respectively. The positive predictive value of a HSD, with our study prevalence, was 0.48. CONCLUSIONS: The HSD classification schema has poor validity when applied to a general working population but improves when applied to workers with current neuropathic symptoms. The high number of false-negative HSDs in the general study population is most likely to be due to the inadequacies of using EDS as the confirmatory test. With a low prevalence of CTS, the positive predictive value for HSDs is poor.

Rotator cuff syndrome: personal, work-related psychosocial and physical load factors.

OBJECTIVE: To identify factors associated with rotator cuff syndrome (RCS) among active workers. METHODS: Seven hundred thirty-three workers in 12 worksites participated in a cross-sectional study with individual structured physical and psychosocial health interviews, physical examinations, and exposure assessments of biomechanical factors. Work organization, including job content or structural constraints, was assessed at the departmental level. Multivariable logistic modeling was used. RESULTS: Fifty-five subjects (7.5%) had RCS. Cases were more likely to report low job security (P < 0.04) and to have very high job structural constraints (P < 0.03). Age and body mass index were marginally significant. Upper arm flexion >or= 45 degrees >or= 15% of time and either duty cycle of forceful exertions >or=9% time (odds ratio = 2.43, 95% CI = 1.04 to 5.68) or forceful pinch >0% [odds ratio = 2.66, 95% CI = 1.26 to 5.59] were significant risk factors. CONCLUSIONS: Long duration of shoulder flexion and forceful exertion (especially pinch) in a job are significant risk factors for RCS. Work organization may impact physical and psychosocial exposures and should be further explored.

Geographical patterns of end-stage renal disease incidence and risk factors in rural and urban areas of South Carolina.

To assess the geographical patterns of end-stage renal disease (ESRD) incidence and to identify the risk factors on the regional differences, the authors conducted an ecological study on incidence of ESRD and related risk factors in the 46 counties of South Carolina (SC). Age and gender adjusted, race specific incidence rates for each county in SC were calculated for the 11,346 ESRD patients of all ages who registered in the United States Renal Data Systems Network 6 from 1990 to 1999. County level exposure measures on population physician density, hospitalization rates of diabetes and hypertension, per capita income, percent college degree, and percent below poverty were evaluated. There was a significant increase in mean incidence rates of ESRD from 1990 to 1999 in SC (p<0.0001). The incidence rates were consistently higher in rural than in urban counties. Population physician density (relative risk (RR) 0.49, 95% confidence interval (95%Cl, 0.41-0.58) and rural residence (adjusted RR 1.66, 95%Cl 1.59-1.74) were significantly associated with ESRD incidence. The strong relationship between ESRD and physician density suggests that access to adequate treatment of diabetes and hypertension is of paramount importance for ESRD prevention, and has important public policy implications.