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Per- and polyfluoroalkyl substances (PFAS) are ubiquitous throughout the United States. Previous studies have shown PFAS exposure to be associated with a reduced immune response. However, the relationship between serum PFAS and antibody levels following SARS-CoV-2 infection or COVID-19 vaccination has not been examined. We examined differences in peak immune response and the longitudinal decline of antibodies following SARS-CoV-2 infection and COVID-19 vaccination by serum PFAS levels in a cohort of essential workers in the United States. We measured serum antibodies using an in-house semi-quantitative enzyme-linked immunosorbent assay (ELISA). Two cohorts contributed blood samples following SARS-CoV-2 infection or COVID-19 vaccination. We used linear mixed regression models, adjusting for age, race/ethnicity, gender, presence of chronic conditions, location, and occupation, to estimate differences in immune response with respect to serum PFAS levels. Our study populations included 153 unvaccinated participants that contributed 316 blood draws over a 14-month period following infection, and 860 participants and 2451 blood draws over a 12-month period following vaccination. Higher perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) concentrations were associated with a lower peak antibody response after infection (p = 0.009, 0.031, 0.015). Higher PFOS, perfluorooctanoic acid (PFOA), PFHxS, and PFNA concentrations were associated with slower declines in antibodies over time after infection (p = 0.003, 0.014, 0.026, 0.025). PFOA, PFOS, PFHxS, and PFNA serum concentrations prior to vaccination were not associated with differences in peak antibody response after vaccination or with differences in decline of antibodies over time after vaccination. These results suggest that elevated PFAS may impede potential immune response to SARS-CoV-2 infection by blunting peak antibody levels following infection; the same finding was not observed for immune response to vaccination., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Allison L Naleway reports a relationship with Pfizer Inc that includes: funding grants. Allison L Naleway reports a relationship with Vir Biotechnology Inc that includes: funding grants. Kurt Hegmann reports a relationship with American College of Occupational and Environmental Medicine that includes: consulting or advisory. Kurt Hegmann reports a relationship with National Institute for Occupational Safety and Health that includes: funding grants. Manjusha Gaglani reports a relationship with Westat Inc that includes: funding grants. Manjusha Gaglani reports a relationship with Vanderbilt University Medical Center that includes: funding grants. Manjusha Gaglani reports a relationship with Abt Associates Inc that includes: funding grants. Manjusha Gaglani reports a relationship with Infectious Diseases and Immunization Committee, Texas Pediatric Society, Texas Chapter of the American Academy of Pediatrics that includes: board membership. Ryan Sprissler reports a relationship with American Council of Life Insurers that includes: speaking and lecture fees. Ryan Sprissler reports a relationship with California legal case Ebers v. Castle Park that includes: consulting or advisory. Ryan Sprissler reports a relationship with Geneticure, Inc. that includes: equity or stocks. Ryan Sprissler reports a relationship with Beckman Coulter that includes: speaking and lecture fees. Ryan Sprissler reports a relationship with Shay Emma Hammer Research Foundation that includes: board membership. Ryan Sprissler has patent issued to Arizona Board of Regents on Behalf of the University of Arizona., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of the study is to assess risk of common musculoskeletal disorders (MSDs) based on cardiovascular disease (CVD) risk scores., Methods: Data from a 9-year prospective cohort of 1224 workers in three states were analyzed. Baseline data included questionnaires, structured interviews, physical examinations, anthropometric measurements, nerve conduction studies, and individualized measurement of job physical factors. Monthly follow-ups were conducted. Framingham risk scores were calculated. A priori case definitions were constructed for carpal tunnel syndrome, lateral epicondylopathy, medial epicondylopathy, and rotator cuff tendinopathy., Results: Adjusted RRs for one or more MSDs increased to 3.90 (95% confidence interval, 2.20-6.90) among those with 10-year cardiovascular disease risk scores greater than 15% and 17.4 (95% confidence interval, 3.85-78.62) among those with more than 4 disorders., Conclusions: Cardiovascular disease factors are strongly associated with the subsequent development of common MSDs. Risks among those with multiple MSDs are considerably stronger., Competing Interests: Conflict of interest: K.T.H. is the Editor-in-Chief of the American College of Occupational and Environmental Medicine’s Evidence-Based Practice Guidelines. D.L.D. has received payments from the University of Wisconsin at Milwaukee (UW System). R.K. has received funding for committee work for the American Board of Anesthesia., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Occupational and Environmental Medicine.)

In a cohort of essential workers in the United States previously infected with SARS-CoV-2, risk factors for reinfection included being unvaccinated, infrequent mask use, time since first infection, and being non-Hispanic Black. Protecting workers from reinfection requires a multipronged approach including up-to-date vaccination, mask use as recommended, and reduction in underlying health disparities.

Importance: Data on the epidemiology of mild to moderately severe COVID-19 are needed to inform public health guidance., Objective: To evaluate associations between 2 or 3 doses of mRNA COVID-19 vaccine and attenuation of symptoms and viral RNA load across SARS-CoV-2 viral lineages., Design, Setting, and Participants: A prospective cohort study of essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah with COVID-19 infection confirmed by reverse transcriptase-polymerase chain reaction testing and lineage classified by whole genome sequencing of specimens self-collected weekly and at COVID-19 illness symptom onset. This analysis was conducted among 1199 participants with SARS-CoV-2 from December 14, 2020, to April 19, 2022, with follow-up until May 9, 2022, reported., Exposures: SARS-CoV-2 lineage (origin strain, Delta variant, Omicron variant) and COVID-19 vaccination status., Main Outcomes and Measures: Clinical outcomes included presence of symptoms, specific symptoms (including fever or chills), illness duration, and medical care seeking. Virologic outcomes included viral load by quantitative reverse transcriptase-polymerase chain reaction testing along with viral viability., Results: Among 1199 participants with COVID-19 infection (714 [59.5%] women; median age, 41 years), 14.0% were infected with the origin strain, 24.0% with the Delta variant, and 62.0% with the Omicron variant. Participants vaccinated with the second vaccine dose 14 to 149 days before Delta infection were significantly less likely to be symptomatic compared with unvaccinated participants (21/27 [77.8%] vs 74/77 [96.1%]; OR, 0.13 [95% CI, 0-0.6]) and, when symptomatic, those vaccinated with the third dose 7 to 149 days before infection were significantly less likely to report fever or chills (5/13 [38.5%] vs 62/73 [84.9%]; OR, 0.07 [95% CI, 0.0-0.3]) and reported significantly fewer days of symptoms (10.2 vs 16.4; difference, -6.1 [95% CI, -11.8 to -0.4] days). Among those with Omicron infection, the risk of symptomatic infection did not differ significantly for the 2-dose vaccination status vs unvaccinated status and was significantly higher for the 3-dose recipients vs those who were unvaccinated (327/370 [88.4%] vs 85/107 [79.4%]; OR, 2.0 [95% CI, 1.1-3.5]). Among symptomatic Omicron infections, those vaccinated with the third dose 7 to 149 days before infection compared with those who were unvaccinated were significantly less likely to report fever or chills (160/311 [51.5%] vs 64/81 [79.0%]; OR, 0.25 [95% CI, 0.1-0.5]) or seek medical care (45/308 [14.6%] vs 20/81 [24.7%]; OR, 0.45 [95% CI, 0.2-0.9]). Participants with Delta and Omicron infections who received the second dose 14 to 149 days before infection had a significantly lower mean viral load compared with unvaccinated participants (3 vs 4.1 log10 copies/μL; difference, -1.0 [95% CI, -1.7 to -0.2] for Delta and 2.8 vs 3.5 log10 copies/μL, difference, -1.0 [95% CI, -1.7 to -0.3] for Omicron)., Conclusions and Relevance: In a cohort of US essential and frontline workers with SARS-CoV-2 infections, recent vaccination with 2 or 3 mRNA vaccine doses less than 150 days before infection with Delta or Omicron variants, compared with being unvaccinated, was associated with attenuated symptoms, duration of illness, medical care seeking, or viral load for some comparisons, although the precision and statistical significance of specific estimates varied.

Background: Although recent studies have identified important risk factors associated with incident carpal tunnel syndrome (CTS), risk factors associated with its severity have not been well explored., Objective: To examine the associations between personal, workplace psychosocial and biomechanical factors and incident work disability among workers with CTS., Methods: Between 2001 and 2010 five research groups conducted coordinated prospective studies of CTS and related work disability among US workers from various industries. Workers with prevalent or incident CTS (N=372) were followed for up to 6.4 years. Incident work disability was measured as: (1) change in work pace or work quality, (2) lost time or (3) job change following the development of CTS. Psychosocial factors were assessed by questionnaire. Biomechanical exposures were assessed by observation and measurements and included force, repetition, duty cycle and posture. HRs were estimated using Cox models., Results: Disability incidence rates per 100 person-years were 33.2 for changes in work pace or quality, 16.3 for lost time and 20.0 for job change. There was a near doubling of risk for job change among those in the upper tertile of the Hand Activity Level Scale (HR 2.17; 95% CI 1.17 to 4.01), total repetition rate (HR 1.75; 95% CI 1.02 to 3.02), % time spent in all hand exertions (HR 2.20; 95% CI 1.21 to 4.01) and a sixfold increase for high job strain. Sensitivity analyses indicated attenuation due to inclusion of the prevalent CTS cases., Conclusion: Personal, biomechanical and psychosocial job factors predicted CTS-related disability. Results suggest that prevention of severe disability requires a reduction of both biomechanical and organisational work stressors., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: The authors report no conflicts of interest.

Objective: This abbreviated version of the American College of Occupational and Environmental Medicine's (ACOEM) Low Back Disorders Guideline reviews the evidence and recommendations developed for non-invasive and minimally invasive management of low back disorders., Methods: Systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking. A total of 70 high-quality and 564 moderate-quality trials were identified for non-invasive low back disorders. Detailed algorithms were developed., Results: Guidance has been developed for the management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 121 specific recommendations., Conclusion: Quality evidence should guide treatment for all phases of managing low back disorders.

Recent studies have shown the 2001 American Conference of Governmental Industrial Hygienists (ACGIH ® ) Threshold Limit Value (TLV ® ) for Hand Activity was not sufficiently protective for workers at risk of carpal tunnel syndrome (CTS). These studies led to a revision of the TLV and Action Limit. This study compares the effect of applying the 2018 TLV vs. the 2001 TLV to predict incident CTS within a large occupational pooled cohort study (n = 4,321 workers). Time from study enrollment to first occurrence of CTS was modeled using Cox proportional hazard regression. Adjusted and unadjusted hazard ratios for incident CTS were calculated using three exposure categories: below the Action Limit, between the Action Limit and TLV, and above the TLV. Workers exposed above the 2001 Action Limit demonstrated significant excess risk of carpal tunnel syndrome, while the 2018 TLV demonstrated significant excess risk only above the TLV. Of 186 total cases of CTS, 52 cases occurred among workers exposed above the 2001 TLV vs. 100 among those exposed above the 2018 value. Eliminating exposures above the 2001 TLV might have prevented 11.2% of all cases of CTS seen in our pooled cohort, vs. 25.1% of cases potentially prevented by keeping exposures below the 2018 value. The 2018 revision of the TLV better protects workers from CTS, a recognized occupational health indicator important to public health. A significant number of workers are currently exposed to forceful repetitive hand activity above these guidelines. Public health professionals should promulgate these new guidelines and encourage employers to reduce hand intensive exposures to prevent CTS and other musculoskeletal disorders.

Objective: American College of Occupational and Environmental Medicine's (ACOEM's) evidence-based guidelines for acute low back pain (LBP) were used to assess relationships between guideline adherence and worker's compensation costs., Methods: Treatments at first appointments were abstracted. Two scoring tools were utilized to assess each patient's treatment plan. One score assessed ACOEM Guideline compliance while the second utilized mean expert scores of the perceived value of each treatment. Claim costs were log-transformed and compared with scores., Results: There is a significant trend between increased compliance and decreasing costs. Medical and total costs trended lower by an average $352.90 and $586.20 per unit of compliance score respectively. No outlier cost claims were in the best guidelines compliance groups., Conclusion: This study shows a statistically significant trend in the relationship between adherence to ACOEM guidelines for initial management of work-related LBP and decreasing claim costs.

Objective: The aim of this study was to summarize evidence-based diagnostic guidelines for low back disorders., Methods: A comprehensive literature review was conducted. A total of 101 articles of high or moderate quality addressing low back disorders diagnostic evaluation met the inclusion criteria. Evidence-based recommendations were developed and graded from (A) to (C) in favor and against the specific diagnostic test, with (A) level having the highest quality body of literature. Expert consensus was employed for insufficient evidence (I) to develop consensus guidance., Results: Recommendations are given for these diagnostic tests: functional capacity evaluations, roentgenograms (x-rays), magnetic resonance imaging (MRI), computerized tomography, myelography, bone scans, single proton emission computed tomography, electromyography, surface electromyography, ultrasound, thermography, fluoroscopy, videofluoroscopy, lumbar discography, MRI discography, and myeloscopy., Conclusion: Diagnostic testing is not indicated for the majority of patients with low back pain.

Introduction: Diagnostic screening tests for carpal tunnel syndrome (CTS) have not been rigorously assessed in large populations., Methods: This study is a cross-sectional analysis from a prospective cohort study. Participants' (n = 1,194) symptoms and disease prevalence were measured. Sensitivity, specificity, and positive and negative predictive values (NPVs) were calculated., Results: When defining CTS as tingling/numbness in at least two median nerve-served digits and an abnormal median nerve conduction study, the prevalence was 8.9%. The sensitivity of paresthesias with nocturnal awakening was 77.4%. The sensitivity of the Phalen sign was 52.8% and that of the Hoffman-Tinel sign was only 37.7%., Discussion: The highest sensitivity (77.4%) for a case definition of CTS in this population of workers was for nocturnal tingling/numbness in a median nerve distribution, and the highest specificity (97.5%) was for continuous tingling/numbness. The Phalen sign has a sensitivity of 52.8% and NPV of 95%, suggesting that the NPV is of particular diagnostic value. Hoffman-Tinel signs seem primarily helpful for the NPV (93.7%)., Level of Evidence: Level II diagnostic study.

Objectives: Working-age adults are disproportionately impacted by opioid misuse. Factors associated with opioid misuse in people with workers compensation (WC) claims are not well studied. WC in some states is a "captured" market making it a more efficient site for researching the opioids epidemic. A pilot study was conducted to identify factors associated with opioid use using a large WC insurer's claims in Utah., Methods: This was a case-control study using a large WC insurer's database. We conducted secondary data analyses of a de-identified dataset originally obtained from the WC insurer. Cases were defined as claims with a morphine equivalent dose (MED)≥50 mg/d in the 30 days after the claim was filed while controls = 0 mg/d., Results: A total of 76 patient's claims (28 cases and 48 controls) were included in the final data analyses. The majority of claimants were male (N = 50, 65.8 percent), worked full time (N = 58, 76.3 percent) and had a mean age of 37.0±11.4 years. The majority of controls filed medical only claims (N = 40, 83.3 percent) while the majority of cases filed indemnity claims (N = 19, 67.9 percent). Cases were prescribed a mean MED of 126.4 (SD = 93.3) within the first month after filing the claim. Most cases visited>3 medical providers (N = 13, 46.4 percent) in the first month after filing the claim while the majority of controls only visited one provider (N = 28, 58.3 percent). Remarkably, the mean number of providers visited within the first month for the cases was 3.8, which was 2-fold greater than the control group. Exploratory multivariate analyses showed that cases were 4.6 times more likely to have visited 2-3 medical providers (p = 0.025), and 41.8 times more likely to have visited more than three medical providers (p < 0.001). Cases had 3.6 higher odds of having been prescribed nonsteroidal anti-inflammatory prescription within the first month as compared to controls (p = 0.014)., Conclusion: This pilot study found risk factors, some of which may be modifiable. We aim to conduct a large study using existing WC data to create a scoring system that identifies those claimants at higher risk of adverse opioid-related events that may have preventive applications at a systems-level.

Background: There is growing use of a job exposure matrix (JEM) to provide exposure estimates in studies of work-related musculoskeletal disorders; few studies have examined the validity of such estimates, nor did compare associations obtained with a JEM with those obtained using other exposures., Objective: This study estimated upper extremity exposures using a JEM derived from a publicly available data set (Occupational Network, O*NET), and compared exposure-disease associations for incident carpal tunnel syndrome (CTS) with those obtained using observed physical exposure measures in a large prospective study., Methods: 2393 workers from several industries were followed for up to 2.8 years (5.5 person-years). Standard Occupational Classification (SOC) codes were assigned to the job at enrolment. SOC codes linked to physical exposures for forceful hand exertion and repetitive activities were extracted from O*NET. We used multivariable Cox proportional hazards regression models to describe exposure-disease associations for incident CTS for individually observed physical exposures and JEM exposures from O*NET., Results: Both exposure methods found associations between incident CTS and exposures of force and repetition, with evidence of dose-response. Observed associations were similar across the two methods, with somewhat wider CIs for HRs calculated using the JEM method., Conclusion: Exposures estimated using a JEM provided similar exposure-disease associations for CTS when compared with associations obtained using the 'gold standard' method of individual observation. While JEMs have a number of limitations, in some studies they can provide useful exposure estimates in the absence of individual-level observed exposures., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: This study aims to quantify the crash risk for truck drivers with multiple comorbid medical conditions, after adjusting for confounders., Methods: This retrospective cohort of 38,184 drivers evaluated concomitant medical conditions and subsequent crash data between January 1, 2005, and October 31, 2012. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated for any cause and preventable crashes of varying severity., Results: Drivers with three or more medical conditions had a significantly increased risk of preventable Department of Transportation (DOT) reportable crashes (HR = 2.53, 95% CI = 1.65 to 3.88) and preventable crashes with injuries (HR = 2.23, 95% CI = 1.09 to 5.31) after adjustment for covariates. Similarly, adjusted HRs were 2.55 (95% CI = 1.37 to 4.73) for any cause DOT-reportable crashes and 3.21 (95% CI = 1.18 to 8.75) for any cause crashes with injuries., Conclusions: Having three concomitant medical conditions may be a statistically significant risk factor for preventable and any cause DOT-reportable crashes and crashes with injuries.

Background: Between 2001 and 2010, six research groups conducted coordinated prospective studies of carpal tunnel syndrome (CTS) incidence among US workers from various industries to estimate exposure-response relationships., Objective: This analysis examined the presence and magnitude of confounding between biomechanical and workplace psychosocial factors and incidence of dominant-hand CTS., Methods: 1605 participants, without CTS at enrolment, were followed for up to 3.5 years (2471 person-years). Demographic information, medical history and workplace psychosocial stress measures were collected at baseline. Individual workplace biomechanical exposures were collected for each task and combined across the workweek using time-weighted averaging (TWA). CTS case criteria were based on symptoms and results of electrophysiological testing. HRs were estimated with Cox proportional hazard models. Confounding was assessed using causal diagrams and an empirical criterion of 10% or greater change in effect estimate magnitude., Results: There were 109 incident CTS cases (IR=4.41/100 person-years; 6.7% cumulative incidence). The relationships between CTS and forceful repetition rate, % time forceful hand exertion and the Threshold Limit Value for Hand Activity Level (TLV-HAL) were slightly confounded by decision latitude with effect estimates being attenuated towards the null (10-14% change) after adjustment. The risk of CTS among participants reporting high job strain was attenuated towards the null by 14% after adjusting for the HAL Scale or the % time forceful hand exertions., Conclusions: Although attenuation of the relationships between CTS and some biomechanical and work psychosocial exposures was observed after adjusting for confounding, the magnitudes were small and confirmed biomechanical and work psychosocial exposures as independent risk factors for incident CTS., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: The goal is to assess the relationships between psychosocial factors and both medial and lateral epicondylitis after adjustment for personal and job physical exposures., Methods: One thousand eight hundred twenty-four participants were included in pooled analyses. Ten psychosocial factors were assessed., Results: One hundred twenty-one (6.6%) and 34 (1.9%) participants have lateral and medial epicondylitis, respectively. Nine psychosocial factors assessed had significant trends or associations with lateral epicondylitis, the largest of which was between physical exhaustion after work and lateral epicondylitis with and odds ratio of 7.04 (95% confidence interval = 2.02 to 24.51). Eight psychosocial factors had significant trends or relationships with medial epicondylitis, with the largest being between mental exhaustion after work with an odds ratio of 6.51 (95% confidence interval = 1.57 to 27.04)., Conclusions: The breadth and strength of these associations after adjustment for confounding factors demonstrate meaningful relationships that need to be further investigated in prospective analyses.

Objective: The aim of the study was to ascertain if cardiovascular (CVD) risk factors are carpal tunnel syndrome (CTS) risk factors., Methods: Analysis of pooled baseline data from two large prospective cohort studies (n = 1824) assessed the relationships between a modified Framingham Heart Study CVD risk score both CTS and abnormal nerve conduction study prevalence. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratio and 95% confidence intervals were calculated for individual risk scores., Results: There was a strong relationship between CVD risk score and both CTS and abnormal nerve conduction study after adjustment for confounders, with odds ratios as high as 4.16 and 7.35, respectively. Dose responses were also observed., Conclusions: In this workplace population, there is a strong association between CVD risk scores and both CTS and abnormal nerve conduction study that persisted after controlling for confounders. These data suggest a potentially modifiable disease mechanism.

Objective: Summarize developed evidence-based diagnostic and treatment guidelines for work-related asthma (WRA)., Methods: Comprehensive literature reviews conducted with article critiquing and grading. Guidelines developed by a multidisciplinary expert panel and peer-reviewed., Results: Evidence supports spirometric testing as an essential early test. Serial peak expiratory flow rates measurement is moderately recommended for employees diagnosed with asthma to establish work-relatedness. Bronchial provocation testing is moderately recommended. IgE and skin prick testing for specific high-molecular weight (HMW) antigens are highly recommended. IgG testing for HMW antigens, IgE testing for low-molecular weight antigens, and nitric oxide testing for diagnosis are not recommended. Removal from exposure is associated with the highest probability of improvement, but may not lead to complete recovery., Conclusion: Quality evidence supports these clinical practice recommendations. The guidelines may be useful to providers who diagnose and/or treat WRA.

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., (© 2015 Wiley Periodicals, Inc.)

Background: Six research groups independently conducted prospective studies of carpal tunnel syndrome (CTS) incidence in 54 US workplaces in 10 US States. Physical exposure variables were collected by all research groups at the individual worker level. Data from these research groups were pooled to increase the exposure spectrum and statistical power., Objective: This paper provides a detailed description of the characteristics of the pooled physical exposure variables and the source data information from the individual research studies., Methods: Physical exposure data were inspected and prepared by each of the individual research studies according to detailed instructions provided by an exposure subcommittee of the research consortium. Descriptive analyses were performed on the pooled physical exposure data set. Correlation analyses were performed among exposure variables estimating similar exposure aspects., Results: At baseline, there were a total of 3010 participants in the pooled physical exposure data set. Overall, the pooled data meaningfully increased the spectra of most exposure variables. The increased spectra were due to the wider range in exposure data of different jobs provided by the research studies. The correlations between variables estimating similar exposure aspects showed different patterns among data provided by the research studies., Conclusions: The increased spectra of the physical exposure variables among the data pooled likely improved the possibility of detecting potential associations between these physical exposure variables and CTS incidence. It is also recognised that methods need to be developed for general use by all researchers for standardisation of physical exposure variable definition, data collection, processing and reduction., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objective: To analyze differences in carpal tunnel syndrome (CTS) prevalence using a combination of electrodiagnostic studies (EDSs) and symptoms using EDS criteria varied across a range of cutpoints and compared with symptoms in both ≥1 and ≥2 median nerve-served digits., Design: Pooled data from 5 prospective cohorts., Setting: Hand-intensive industrial settings, including manufacturing, assembly, production, service, construction, and health care., Participants: Employed, working-age participants who are able to provide consent and undergo EDS testing (N=3130)., Interventions: None., Main Outcome Measures: CTS prevalence was estimated while varying the thresholds for median sensory latency, median motor latency, and transcarpal delta latency difference. EDS criteria examined included the following: median sensory latency of 3.3 to 4.1 milliseconds, median motor latency of 4.1 to 4.9 milliseconds, and median-ulnar sensory difference of 0.4 to 1.2 milliseconds. EDS criteria were combined with symptoms in ≥1 or ≥2 median nerve-served digits. EDS criteria from other published studies were applied to allow for comparison., Results: CTS prevalence ranged from 6.3% to 11.7%. CTS prevalence estimates changed most per millisecond of sensory latency compared with motor latency or transcarpal delta. CTS prevalence decreased by 0.9% to 2.0% if the criteria required symptoms in 2 digits instead of 1., Conclusions: There are meaningful differences in CTS prevalence when different EDS criteria are applied. The digital sensory latency criteria result in the largest variance in prevalence., (Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Objectives: This paper aimed to quantify exposure-response relationships between the American Conference of Governmental Industrial Hygienists' (ACGIH) threshold limit value (TLV) for hand-activity level (HAL) and incidence of carpal tunnel syndrome (CTS)., Methods: Manufacturing and service workers previously studied by six research institutions had their data combined and re-analyzed. CTS cases were defined by symptoms and abnormal nerve conduction. Hazard ratios (HR) were calculated using proportional hazards regression after adjusting for age, gender, body mass index, and CTS predisposing conditions., Results: The longitudinal study comprised 2751 incident-eligible workers, followed prospectively for up to 6.4 years and contributing 6243 person-years of data. Associations were found between CTS and TLV for HAL both as a continuous variable [HR 1.32 per unit, 95% confidence interval (95% CI) 1.11-1.57] and when categorized using the ACGIH action limit (AL) and TLV. Those between the AL and TLV and above the TLV had HR of 1.7 (95% CI 1.2-2.5) and 1.5 (95% CI 1.0-2.1), respectively. As independent variables (in the same adjusted model) the HR for peak force (PF) and HAL were 1.14 per unit (95% CI 1.05-1.25), and 1.04 per unit (95% CI 0.93-1.15), respectively., Conclusion: Those with exposures above the AL were at increased risk of CTS, but there was no further increase in risk for workers above the TLV. This suggests that the current AL may not be sufficiently protective of workers. Combinations of PF and HAL are useful for predicting risk of CTS.