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Objective: Assessment of possible relationships between work-related psychosocial measures and self-reported low back pain (LBP) outcomes in a large pooled dataset of 1929 participants from 82 facilities in the United States., Methods: Pooled data from three prospective cohort studies were used to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for relationships between psychosocial factors and the LBP outcomes. Personal and occupational confounders were controlled for in adjusted Logistic regression models., Results: Supervisor support and job satisfaction were significantly (P < 0.05) related to all three LBP outcomes. Other psychosocial factors were significantly (P < 0.05) associated with at least one of the LBP outcomes. Adjusted ORs ranged from approximately 1.50 to 3.50 for most associations., Conclusions: There is a significant relationship between work-related psychosocial measures and LBP outcomes.

Objective: To assess the effect of morphine equivalent dose-days (MED-D) on the total cost for acute low back pain (LBP) workers' compensation claims., Methods: Simple random samples of 123 opioid and 141 nonopioid acute LBP claims were obtained. Opioid claims were divided into low, medium, and high subgroups for MED-D, MED, and prescription duration. Subgroup mean total costs were compared to the nonopioid group using multivariate regression analyses., Results: MED-D and prescription duration were each, respectively, associated with significantly increased total costs at both medium and high levels. Increasing MED had a negative association with total cost, though stratification by duration abrogated this perceived trend. Interaction testing indicated MED and duration together better explained cost than MED alone., Conclusion: MED-D is a better predictor of total cost in acute LBP claims than MED alone.

Introduction: Some studies show that truck drivers use tobacco and other stimulants to stay awake as they drive. Despite their increased risks for many of tobacco-related health disparities, there is limited engagement of truck drivers in smoking cessation programs. The objective of this study was to describe smoking characteristics and identify their preferred smoking cessation methods among truck drivers., Methods: This was a cross-sectional mixed methods study. Participants were truck drivers recruited at trucking companies in Utah in 2019. Participants were either individually interviewed (n = 4), or filled out a survey (n = 33). We conducted qualitative data analysis of the interviews followed by descriptive statistics of smoking and cessation characteristics from the survey., Results: Reasons for smoking included, staying awake, stress reduction, or something to do while driving. Of the drivers surveyed, 68.8% were daily smokers while 97% had smoked at least 100 cigarettes in their life time. The mean number of cigarettes per day (cpd) was 15.7, and 25 among those who had 10 or more cpd. Sixty-one percent had made at least a quit attempt. In addition to counseling or brief advice, 68% reported interest in using Nicotine Replacement Therapy (NRT) either as gum or patch to help them quit. 21% reported interest in telephone text messaging to engage them in treatment., Conclusion: Cigarette smoking is a public health problem among truck drivers. Our findings suggest that truck drivers are interested in quitting smoking. Evidence based interventions tailored to this population are needed to help them quit and reduce their smoking-related morbidity., Competing Interests: Declaration of conflicting interests:The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2020.)

Introduction: Commercial motor vehicle drivers, such as truck drivers, experience unique health, lifestyle, and occupational challenges directly associated with their profession., Methods: All participants in this multistate cross-sectional study completed questionnaire measurements. Participants were categorized with metabolic syndrome (MetS) if they had at least three of the five modified criteria used in the joint scientific statement on metabolic syndrome., Results: Overall MetS prevalence was 52.4% (n = 428) of the 817 participants. Prevalence of MetS criteria were waist circumference (n = 634, 77.0%), low HDL cholesterol (n = 580, 71.0%), elevated triglycerides (n = 552, 67.6%), elevated blood pressure (n = 175, 21.2%), and elevated hemoglobin A1c (n = 97, 11.9%). Truck drivers were 2.7 times more likely to have MetS compared to the general working population., Conclusion: Truck drivers in the United States have a high prevalence of MetS compared to the general working population.

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.

Based on experiments conducted in low wind speed and calm air environments, the current International Organization for Standardization (ISO) and European Committee for Standardization (CEN) convention modeling human aerosol inhalability (i.e. aspiration efficiency) may not be valid when wind speeds are less than 0.5 ms-1. Additionally, the convention is based primarily on mouth breathing data and aerosols with aerodynamic diameters smaller than 100 µm. Since the convention's development, experimental inhalation data at wind speeds lower than 0.5 ms-1 for nose, mouth, and oronasal breathing have been generated for aerosols in a wider range of sizes (1.5-135 µm). These data were gathered and modeled with the intention of providing a simple convention recommendation for inhalability in low wind speed (>0 to <0.5 ms-1) and calm air (~0 ms-1) conditions to the ISO Technical Committee (TC) 146, Subcommittee 2, Working Group (WG) 1 ('Particle Size-Selective Sampling and Analysis'), as it relates to standard ISO 7708, and to CEN TC 137/WG 3, as it relates to standard EN 481. This paper presents several equations as possibilities, all relating aspiration efficiency to aerodynamic diameter. The equation AE=1+0.000019dae2-0.009788dae stands out as a possible new convention. This polynomial model balances simplicity and fit while addressing the weakness of the current convention., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Objective: Commercial motor vehicle (CMV) drivers face many challenges to their health, including poor diet, disease, and crash risk. This study quantifies relationships between the percentage of calories from fat (PCF) and markers of poor health, many of which are associated with increased crash risk., Methods: Cross-sectional data from 790 CMV drivers were analyzed. PCF were estimated using the National Cancer Institute Percentage Energy from Fat Screener. Adjusted odds ratios (ORs) were calculated., Results: The highest category of PCF (>38.2%) was statistically significantly more likely to not exercise (OR = 2.08), have sleep apnea (OR = 2.31), snore (OR = 1.90), smoke (OR = 2.28), and use alcohol (OR = 1.87) after adjustments., Conclusion: Meaningful relationships between PCF and poor health indicators exist. These indicators may provide an intervention to improve the health and safety of CMV drivers.

Objective: The primary goal of this cross-sectional analysis was to determine the relationships between self-reported low back pain (LBP) ratings and use of opioid medications., Methods: At baseline, subjects completed a computerized questionnaire. Structured interviews were conducted by residents or certified therapists under the direction of board-certified physicians., Results: There was a statistically significant nonlinear relationship between lifetime prevalence of worst LBP rating (0 to 10) and lifetime prevalence of opioid use. Those with a low pain rating for worst lifetime LBP and those with high LBP ratings were significantly more likely to have been prescribed opioids. Surprisingly, those with moderate pain ratings were the least likely to have used opioids., Conclusion: This study found a higher use of opioids between workers with low and high severe pain rating then those with moderate pain. We also found an increase of opioid use for severe pain.

Objective: The aim of this study was to determine the efficacy of an evidence-based opioid guidelines-based program implemented at the largest worker's compensation insurer in Utah., Methods: All new claims, including surgeries, were included. Pre- and post-intervention comparisons included percentage of claims treated with an opioid, provision of a second opioid prescription, opioid use above 50 mg morphine equivalent dose (MED), opioid use more than 90 mg MED, and opioid use over 90 days., Results: There were significant (P < 0.001) reductions in all primary outcomes, with a reduction in MEDs in the 18 months after implementation totaling 65,502 mg., Conclusion: This program significantly reduced the usage of opioids among acute claims. The year of program implementation, Utah experienced a 19.8% reduction in opioid-related fatalities, which may be partly related to the reduction in MEDs. Regardless, this study suggests that the implementation of an evidence-based guideline is impactful and feasible.

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.

Background: Low back pain (LBP) is a common and costly problem throughout the United States. To achieve a greater understanding of the occupational risk factors, the National Institute for Occupational Safety and Health (NIOSH) funded a low back health effects consortium, which performed several surveillance studies throughout the United States. This study combines data from the consortium research groups resulting in a data set with nearly 2000 workers in various regions of the country. The purpose of this paper is to examine prevalence and personal risk factors of low back health effects among these workers., Methods: There were three common questions regarding history of low back health effects in the past 12 months including 1) have you had LBP lasting 7 days, 2) have you sought medical care for LBP, and 3) have you taken time off work due to LBP. The questionnaire included demographic questions. There were five data collections institutions or sites including NIOSH, Ohio State University, University of Wisconsin-Milwaukee, Texas A&M University, and University of Utah., Results: The 12-month period prevalence of low back pain lasting 7 days, seeking medical care, and lost time due to LBP were 25, 14 and 10%, respectively. There were no statistically significant differences in gender, age or weight between cases and non-cases for any prevalence measure. The height of workers was significantly greater in the cases compared to non-cases for all three prevalence definitions. There were significant differences among the sites on the prevalence of seeking medical care for LBP and lost time due to LBP. The Ohio State University had significantly higher prevalence rates for seeking medical care and lost time due to LBP than University of Wisconsin, University of Utah, or Texas A&M University., Conclusion: LBP, the least severe low back health effect studied, had the highest prevalence (25%) and lost time due to LBP, the most severe low back health effect studied, had the lowest prevalence (10%) among nearly 2000 US manual material handling workers. There was a significant site or regional influence in prevalence rates for seeking medical care and lost time due to LBP.

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.

Objectives: Identify if Carpal tunnel syndrome (CTS) symptoms vary by measured biomechanical exposures., Methods: A nested prospective cohort within a large, multicenter, 8-year cohort study. The CTS case definition was tingling/numbness in 2+ median nerve-served digits plus a nerve conduction study consistent with CTS. Workers were assigned to: (1) low (strain index [SI] less than or equal to 6.1), and (2) high (SI more than 6.1) job groups., Results: Among 1201 workers, 106 had CTS. Those in the high SI group became and remained symptom-free for at least 3 months, faster than the low SI group, adjusted hazard ratio (HR) = 2.07 (95% confidence interval [CI] = 1.21 to 3.56, P = 0.008). Only surgical release trended towards resolving CTS. Light duty had no impact, and job change was associated with delayed symptoms resolution., Conclusions: High biomechanical exposures paradoxically predicted faster improvement in CTS and light duty did not result in symptom resolution.

Objective: To quantify sensitivity and specificity of the tender points and demonstrate how variability in case definition impacts prevalence of lateral epicondylitis (LE)., Methods: Baseline data analyzed from 1216 workers from the WISTAH study, a multicenter prospective cohort study of upper extremity musculoskeletal disorders. All workers completed computerized questionnaires, structured interviews, and two independent physical examinations in accordance with an established protocol., Results: The prevalence of LE differed based on case definition ranging from 4.7% to 12.1%. Sensitivity was low for tender points 1 to 4 ranging from 6.8% to 34.6%. Specificity was high for tender points 1 to 4 ranging from 95.2% to 97.9%., Conclusions: The prevalence of lateral epicondylitis differs markedly based on case definition used, ranging more than two-fold. Standardization of a case definition is essential to allow for comparisons across studies.

Objective: Accurate and reliable shoulder tendinopathy examination maneuvers are essential for diagnosing and treating shoulder pain; however, studies have reported varying results as to the accuracy of common maneuvers. Thus, data from a large, cross-sectional study were used to systematically quantify the reliability and accuracy of clinical diagnostic tests., Methods: Baseline data from the WISTAH cohort study were used to evaluate inter-tester reliability and accuracy of common provocative shoulder examination tests compared with a case definition of shoulder tendinitis., Results: Inter-tester reliability showed reliable consistency between providers with kappa coefficients between 89.5% and 94.8% for all tests. However, sensitivity was generally poor (3.0% to 60.6%). Specificity was consistently high (96.2% to 99.6%)., Conclusion: Common shoulder provocative tests show low sensitivity but high specificity, which implies that the primary utility of examination maneuvers is for their negative predictive values.

Background: Glenohumeral pain and rotator cuff tendinopathy (RCT) are common musculoskeletal complaints with high prevalence among working populations. The primary proposed pathophysiologic mechanisms are sub-acromial RC tendon impingement and reduced tendon blood flow. Some sleep postures may increase subacromial pressure, potentially contributing to these postulated mechanisms. This study uses a large population of workers to investigate whether there is an association between preferred sleeping position and prevalence of: (1) shoulder pain, and (2) rotator cuff tendinopathy., Methods: A cross-sectional analysis was performed on baseline data from a multicenter prospective cohort study. Participants were 761 workers who were evaluated by questionnaire using a body diagram to determine the presence of glenohumeral pain within 30 days prior to enrollment. The questionnaire also assessed primary and secondary preferred sleep position(s) using 6 labeled diagrams. All workers underwent a structured physical examination to determine whether RCT was present. For this study, the case definition of RCT was glenohumeral pain plus at least one of a positive supraspinatus test, painful arc and/or Neer's test. Prevalence of glenohumeral pain and RCT were individually calculated for the primary and secondary sleep postures and odds ratios were calculated., Results: Age, sex, Framingham cardiovascular risk score and BMI had significant associations with glenohumeral pain. For rotator cuff tendinopathy, increasing age, Framingham risk score and Hand Activity Level (HAL) showed significant associations. The sleep position anticipated to have the highest risk of glenohumeral pain and RCT was paradoxically associated with a decreased prevalence of glenohumeral pain and also trended toward being protective for RCT. Multivariable logistic regression showed no further significant associations., Conclusion: This cross-sectional study unexpectedly found a reduced association between one sleep posture and glenohumeral pain. This cross-sectional study may be potentially confounded, by participants who are prone to glenohumeral pain and RCT may have learned to avoid sleeping in the predisposing position. Longitudinal studies are needed to further evaluate a possible association between glenohumeral pain or RCT and sleep posture as a potential risk factor.

Objective: The aim of the study was to assess the relationship between leisure time exercise and whether workers ever had modified duty or lost time (MD/LT) due to low back pain (LBP) in an occupational cohort., Methods: Workers (N = 827) completed a structured interview assessing characteristics of their LBP, whether or not the pain caused modified or lost work time, and their participation in leisure time exercise. Odds ratio of modified/lost time and minutes of exercise participation were assessed., Results: Workers who participated in over 316 min/wk of leisure time exercise incurred significantly less modified/lost time, adjusted odds ratio = 0.46 (95% confidence interval, 0.23 to 0.98). There also lies a significant trend between increases in leisure time exercise and reductions in modified/lost time (P = 0.0016)., Conclusion: These results suggest exercise reduces risk of MD/LT from LBP.

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.)

The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value for hand activity level (TLV for HAL) have been shown to be associated with prevalence of distal upper-limb musculoskeletal disorders such as carpal tunnel syndrome (CTS). The SI and TLV for HAL disagree on more than half of task exposure classifications. Similarly, time-weighted average (TWA), peak, and typical exposure techniques used to quantity physical exposure from multi-task jobs have shown between-technique agreement ranging from 61% to 93%, depending upon whether the SI or TLV for HAL model was used. This study compared exposure-response relationships between each model-technique combination and prevalence of CTS. Physical exposure data from 1,834 workers (710 with multi-task jobs) were analyzed using the SI and TLV for HAL and the TWA, typical, and peak multi-task job exposure techniques. Additionally, exposure classifications from the SI and TLV for HAL were combined into a single measure and evaluated. Prevalent CTS cases were identified using symptoms and nerve-conduction studies. Mixed effects logistic regression was used to quantify exposure-response relationships between categorized (i.e., low, medium, and high) physical exposure and CTS prevalence for all model-technique combinations, and for multi-task workers, mono-task workers, and all workers combined. Except for TWA TLV for HAL, all model-technique combinations showed monotonic increases in risk of CTS with increased physical exposure. The combined-models approach showed stronger association than the SI or TLV for HAL for multi-task workers. Despite differences in exposure classifications, nearly all model-technique combinations showed exposure-response relationships with prevalence of CTS for the combined sample of mono-task and multi-task workers. Both the TLV for HAL and the SI, with the TWA or typical techniques, appear useful for epidemiological studies and surveillance. However, the utility of TWA, typical, and peak techniques for job design and intervention is dubious.

Background: Truck drivers face many health challenges, including lifestyle, diet, inactivity, stressors, and social support., Methods: A repeated cross-sectional analysis compared 88,246 truck drivers with data from (n = 11 918) the National Health and Nutrition Examination Survey (NHANES). Trends over time for body mass index (BMI), high blood pressure, diabetes mellitus, heart disease, and sleep disorders were analyzed, adjusting for potential confounders., Results: Truck drivers had significantly worsening health metrics between 2005 and 2012 compared to NHANES participants. Truck drivers were significantly more likely to be obese and morbidly obese with prevalence odds ratios (POR) and 95% confidence intervals (95%CI) of 1.99 (1.87, 2.13) and 2.34 (2.16, 2.54), respectively. Measured blood pressure, self-reported high blood pressure, diabetes mellitus, and heart disease all significantly increased. Also, sleep disorders increased among truck drivers from 2005 to 2012 (POR = 6.55, 95%CI 5.68, 7.55)., Conclusion: These data suggest disproportionate increases in poor health among truck drivers from 2005 to 2012., (© 2017 Wiley Periodicals, Inc.)

Background: The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value for Hand Activity Level (TLV for HAL) use different constituent variables to quantify task physical exposures. Similarly, time-weighted-average (TWA), Peak, and Typical exposure techniques to quantify physical exposure from multi-task jobs make different assumptions about each task's contribution to the whole job exposure. Thus, task and job physical exposure classifications differ depending upon which model and technique are used for quantification. This study examines exposure classification agreement, disagreement, correlation, and magnitude of classification differences between these models and techniques., Methods: Data from 710 multi-task job workers performing 3,647 tasks were analyzed using the SI and TLV for HAL models, as well as with the TWA, Typical and Peak job exposure techniques. Physical exposures were classified as low, medium, and high using each model's recommended, or a priori limits. Exposure classification agreement and disagreement between models (SI, TLV for HAL) and between job exposure techniques (TWA, Typical, Peak) were described and analyzed., Results: Regardless of technique, the SI classified more tasks as high exposure than the TLV for HAL, and the TLV for HAL classified more tasks as low exposure. The models agreed on 48.5% of task classifications (kappa = 0.28) with 15.5% of disagreement between low and high exposure categories. Between-technique (i.e., TWA, Typical, Peak) agreement ranged from 61-93% (kappa: 0.16-0.92) depending on whether the SI or TLV for HAL was used., Conclusions: There was disagreement between the SI and TLV for HAL and between the TWA, Typical and Peak techniques. Disagreement creates uncertainty for job design, job analysis, risk assessments, and developing interventions. Task exposure classifications from the SI and TLV for HAL might complement each other. However, TWA, Typical, and Peak job exposure techniques all have limitations. Part II of this article examines whether the observed differences between these models and techniques produce different exposure-response relationships for predicting prevalence of carpal tunnel syndrome.

Introduction: Previous studies have reported higher wrist ratios (WR) related to carpal tunnel syndrome (CTS) but have not assessed effect modification by obesity and may have inadequately controlled for confounders., Methods: Baseline data of a multicenter prospective cohort study were analyzed. CTS was defined by nerve conduction study (NCS) criteria and symptoms., Results: Among the 1,206 participants, a square-shaped wrist was associated with CTS after controlling for confounders (prevalence ratio = 2.27; 95% confidence interval [95% CI], 1.33-3.86). Body mass index (BMI) was a strong effect modifier on the relationship between WR and both CTS and abnormal NCS results, with normal weight strata of rectangular versus square wrists = 8.18 (95% CI, 1.63-49.96) and 7.12 (95% CI, 2.19-23.16), respectively., Discussion: A square wrist is significantly associated with CTS after controlling for confounders. Effect modification by high BMI masked the eightfold magnitude adjusted relationship seen between WR and CTS among normal weight participants. Muscle Nerve 56: 1047-1053, 2017., (© 2017 Wiley Periodicals, Inc.)

Background: The pathophysiology of lateral epicondylitis (LE) is unclear. Recent evidence suggests some common musculoskeletal disorders may have a basis in cardiovascular disease (CVD) risk factors. Thus, we examined CVD risks as potential LE risks., Methods: Workers (n = 1824) were enrolled in two large prospective studies and underwent structured interviews and physical examinations at baseline. Analysis of pooled baseline data assessed the relationships separately between a modified Framingham Heart Study CVD risk score and three prevalence outcomes of: 1) lateral elbow pain, 2) positive resisted wrist or middle finger extension, and 3) a combination of both symptoms and at least one resisted maneuver. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratios (ORs) and 95% Confidence Intervals (CIs) were calculated., Results: There was a strong relationship between CVD risk score and lateral elbow symptoms, resisted wrist or middle finger extension and LE after adjustment for confounders. The adjusted ORs for symptoms were as high as 3.81 (95% CI 2.11, 6.85), for positive examination with adjusted odds ratios as high as 2.85 (95% CI 1.59, 5.12) and for combined symptoms and physical examination 6.20 (95% CI 2.04, 18.82). Relationships trended higher with higher CVD risk scores., Conclusions: These data suggest a potentially modifiable disease mechanism for LE.

Objective: Recent evidence has found potential associations between cardiovascular disease (CVD) risk factors and common musculoskeletal disorders. We evaluated possible associations between risk factors and both glenohumeral joint pain and rotator cuff tendinopathy., Methods: Data from WISTAH hand study participants (n = 1226) were assessed for associations between Framingham Heart Study CVD risk factors and both health outcomes., Results: A strong association was observed between CVD risk scores and both glenohumeral joint pain and rotator cuff tendinopathy. Peak odds ratios (ORs) of the adjusted models were 4.55 [95% confidence interval (95% CI) 1.97 to 10.31] and 5.97 (95% CI 2.12 to 16.83), respectively. The results show a dose-response trend of increasing risk., Conclusions: Individual risk factors were associated with both outcomes. Combined, CVD risk factors demonstrated a strong correlation with glenohumeral joint pain and an even stronger correlation with rotator cuff tendinopathy. Results suggest a potentially modifiable disease mechanism.

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/.)

Background: Monitoring core body temperature to identify heat strain in workers engaged in hot work in heat stress environments is intrusive and expensive. Nonintrusive, inexpensive methods are needed to calculate individual Physiological Strain Index (PSI)., Objective: Thermal imaging and heart rate monitoring were used in this study to calculate Physiological Strain Index (PSI) from thermal imaging temperatures of human subjects wearing thermal protective garments during recovery from hot work., Methods: Ten male subjects were evaluated for physiological strain while participating in hot work. Thermal images of the head and neck were captured with a high-resolution thermal imaging camera concomitant with measures of gastrointestinal and skin temperature. Lin's concordance correlation coefficient (rho&#95;c), Pearson's coefficient (r) and bias correction factor (C-b) were calculated to compare thermal imaging based temperatures to gastrointestinal temperatures. Calculations of PSI based thermal imaging recorded temperatures were compared to gastrointestinal based PSI., Results: Participants reached a peak PSI of 5.2, indicating moderate heat strain. Sagittal measurements showed low correlation (rho&#95;c=0.133), moderate precision (r=0.496) and low accuracy (C&#95;b=0.269) with gastrointestinal temperature. Bland-Altman plots of imaging measurements showed increasing agreement as gastrointestinal temperature rose; however, the Limits of Agreement (LoA) fell outside the ±0.25C range of clinical significance. Bland-Altman plots of PSI calculated from imaging measurements showed increasing agreement as gastrointestinal temperature rose; however, the LoA fell outside the ±0.5 range of clinical significance., Conclusion: Results of this study confirmed previous research showing thermal imagery is not highly correlated to body core temperature during recovery from moderate heat strain in mild ambient conditions. Measurements display a trend toward increasing correlation at higher body core temperatures. Accuracy was not sufficient at mild to moderate heat strain to allow calculation of individual physiological stress., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Application and interpretation of statistical evaluation of relationships is a necessary element in biomedical research. Statistical analyses rely on P value to demonstrate relationships. The traditional level of significance, P<0.05, can be negatively impacted by small sample size, bias, and random error, and has evolved to include interpretation of statistical trends, correction factors for multiple analyses, and acceptance of statistical significance for P>0.05 for complex relationships such as effect modification., Competing Interests: The authors have no conflicts of interest to declare.

Objective: The aim of this study was to identify relationships between work organizational variables (job rotation, overtime work, having a second job, and work pacing) (These work organizational variables and their relationships with biomechanical and psychosocial exposures were studied previously and published in a separate paper.) and health outcome measures [carpal tunnel syndrome (CTS), lateral and medial epicondylitis (LEPI/MEPI)]., Methods: Using a pooled baseline cohort of 1834 subjects, the relationships were studied using logistic regression models., Results: Varied degrees of associations between the work organizational and outcomes variables were found. Job rotation was significantly associated with being a CTS case [odds ratio (OR) = 1.23, 95% confidence interval (95% CI): 1.00 to 1.50]. Overtime work was significantly associated with lower LEPI prevalence (OR = 0.48, 95% CI: 0.28 to 0.84). No statistically significant associations were found between having a second job and different work pacing and any of the three health outcome measures., Conclusions: Work organizational variables were only partially associated with the studied health outcomes.

Objective: This study assesses relationships between the Framingham cardiovascular disease risk (CVD risk) score and prevalence of US Department of Transportation (DOT)-reportable crashes in commercial motor vehicle (CMV) drivers, after controlling for potential confounders., Methods: Data were analyzed from CMV drivers (N = 797) in a large cross-sectional study. CVD risk was calculated for each driver. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) between CVD risk and DOT-reportable crashes were calculated., Results: Drivers in the two highest CVD risk groups had significantly higher likelihood of crash (OR = 2.08, 95% CI = 1.20 to 3.63 and OR = 1.99, 95% CI = 1.05 to 3.77, respectively) after adjusting for confounders. There was a significant trend of increasing prevalence of crashes with an increasing CVD risk score (P = 0.0298)., Conclusion: Drivers with a high CVD risk had a higher likelihood of a crash after controlling for confounders.

Statistical analyses are a key part of biomedical research. Traditionally surgical research has relied upon a few statistical methods for evaluation and interpretation of data to improve clinical practice. As research methods have increased in both rigor and complexity, statistical analyses and interpretation have fallen behind. Some evidence suggests that surgical research studies are being designed and analyzed improperly given the specific study question. The goal of this article is to discuss the complexities of surgical research analyses and interpretation, and provide some resources to aid in these processes., Competing Interests: The authors have no conflicts of interest to declare.

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.

Introduction: The temporal relationship between disease and disability progression in Parkinson disease (PD) is not well understood. Our objective was to describe the natural, multidimensional trajectory of disability in persons with PD over a two-year period., Methods: We conducted a multi-center, prospective cohort study involving four institutions. Data were collected at baseline and at 6-month intervals over 2 years using standardized clinical tests representing three World Health Organization defined disability domains: impairment, activity limitation, and participation restriction. Unadjusted mixed effects growth models characterized trajectories of disability in the three disability domains. The data set was analyzed using restricted maximum likelihood (REML) estimation. Standardized estimates of change were also computed using Cohen's d for each measure., Results: Of the 266 enrolled participants, we analysed data from individuals who participated in at least 3 assessments (n = 207, 79%). Rates of disability progression over the 2-year period differed across domains. Moderate effects were detected for motor impairment (d = .28) and walking-related activity limitation (gait-related balance (d = .31); gait speed (d = .30)). Marginal effects were noted for upper extremity-related activity limitation (d = .11) and health-related quality of life participation restriction (d = .08)., Conclusions: The natural trajectory of walking-related activity limitation was the most potent indicator of evolving disability, suggesting that routine assessment of walking and periodic rehabilitation is likely to be warranted for many persons with PD. Natural trajectories of disability provide important comparison data for future intervention studies., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated., Practitioner Summary: The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors.

In addition to chemical composition, the site of deposition of inhaled particles is important for determining the potential health effects from an exposure. As a result, the International Organization for Standardization adopted a particle deposition sampling convention. This includes extrathoracic particle deposition sampling conventions for the anterior nasal passages (ET1) and the posterior nasal and oral passages (ET2). This study assessed how well a polyurethane foam insert placed in an Institute of Occupational Medicine (IOM) sampler can match an extrathoracic deposition sampling convention, while accounting for possible static buildup in the test particles. In this way, the study aimed to assess whether neutralized particles affected the performance of this sampler for estimating extrathoracic particle deposition. A total of three different particle sizes (4.9, 9.5, and 12.8 µm) were used. For each trial, one particle size was introduced into a low-speed wind tunnel with a wind speed set a 0.2 m/s (∼40 ft/min). This wind speed was chosen to closely match the conditions of most indoor working environments. Each particle size was tested twice either neutralized, using a high voltage neutralizer, or left in its normal (non neutralized) state as standard particles. IOM samplers were fitted with a polyurethane foam insert and placed on a rotating mannequin inside the wind tunnel. Foam sampling efficiencies were calculated for all trials to compare against the normalized ET1 sampling deposition convention. The foam sampling efficiencies matched well to the ET1 deposition convention for the larger particle sizes, but had a general trend of underestimating for all three particle sizes. The results of a Wilcoxon Rank Sum Test also showed that only at 4.9 µm was there a statistically significant difference (p-value = 0.03) between the foam sampling efficiency using the standard particles and the neutralized particles. This is interpreted to mean that static buildup may be occurring and neutralizing the particles that are 4.9 µm diameter in size did affect the performance of the foam sampler when estimating extrathoracic particle deposition.

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.

Objective: This large, cross-sectional study calculated prevalence of disorders and assessed factors associated with self-reported lifetime crashes., Methods: Truck drivers (n = 797) completed computerized questionnaires reporting crashes, demographics, psychosocial factors, and other elements, as well as had taken measurements (eg, height, weight, serum, and blood pressure)., Results: Most drivers were male (n = 685, 85.9%), and the mean body mass index was 32.9 ± 7.5  kg/m2 with 493 (61.9%) being obese. Many drivers (n = 326, 39.9%) experienced at least one, with 132 (16.6%) having multiple, lifetime, reportable crashes. Many factors were associated with crashes, including increasing age, increasing truck driving experience, male sex, alcohol, low back pain, heart disease, and feeling tense. The most consistent associations with crashes were pulse pressure, cell phone use, and feeling physically exhausted after work., Conclusions: Modifiable factors associated with self-reported crashes were identified. These suggest targeted interventions may reduce risks of crashes.

Objective: To assess relationships and trends over time in individual conditions and multiple conditions among a large sample of independent, nonoverlapping truck drivers using a repeated cross-sectional study design., Methods: Commercial driver medical examinations were conducted on 95,567 commercial drivers between January 1, 2005, and October 31, 2012. Specific medical conditions that have been identified by the Federal Motor Carrier Safety Administration's Medical Review Board as possibly increasing crash risk were examined. Prevalence and trends over time were analyzed., Results: A total of 8 of the 13 conditions significantly increased from 2005 to 2012. Prevalence of multiple concomitant conditions also increased, with prevalence odds ratios as high as 7.39 (95% confidence interval, 3.92 to 13.98) for four or more conditions in 2012 as compared with 2005., Conclusions: Individual and multiple conditions thought to be associated with increased crash risk significantly increased between 2005 and 2012.

Objective: To ascertain worker health characteristics and psychosocial factors associated with changes in body weight and total cholesterol (TC) among two production operation populations., Methods: We performed descriptive and predictive analysis of questionnaire data and biomedical measurements from two prospective cohort studies. Our key outcomes were changes in weight, and TC over 5 to 10 years between baseline and exit assessments., Results: A total of 146 subjects were analyzed. Increases in weight were associated with belief in being overweight and baseline overweight and obesity. Increases in TC levels were associated with female sex, belief that TC levels were "not good," and feeling depressed., Conclusions: Most of the reported associations with increases in weight and TC levels are amenable to interventions and may be a target for workplace intervention programs.

Objective: The objective of this study was to assess relationships between body mass index (BMI) and comorbid conditions within a large sample of truck drivers., Methods: Commercial driver medical examination data from 88,246 commercial drivers between 2005 and 2012 were analyzed for associations between BMI, medical disorders, and driver certification., Results: Most drivers were obese (53.3%, BMI >30.0 kg/m) and morbidly obese (26.6%, BMI >35.0 kg/m), higher than prior reports. Obese drivers were less likely to be certified for 2 years and more likely to report heart disease, hypertension, diabetes mellitus, nervous disorders, sleep disorders, and chronic low back pain (all P < 0.0001). There are relationships between multiple potentially disqualifying conditions and increasing obesity (P < 0.0001). Morbid obesity prevalence increased 8.9% and prevalence of three or more multiple conditions increased fourfold between 2005 and 2012., Conclusions: Obesity is related to multiple medical factors as well as increasing numbers of conditions that limit driving certification.

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.)

Objective: To describe demographic and health characteristics, and factors associated with obesity among production workers., Methods: This cross-sectional study analyzed baseline data from two occupational cohorts. Regression modeling was used to assess associations between worker characteristics and obesity., Results: A total of 1974 subjects were included in these analyses. The mean body mass index was 29.5 kg/m (SD = 6.5). Having smoked in the past and currently smoking decreased the odds of being obese in the WISTAH Distal Upper Extremity cohort, whereas those feeling depressed had increased odds of being obese. Being a Pacific Islander/Native Hawaiian and married increased the odds of obesity in the BackWorks Low Back Pain cohort., Conclusions: Factors associated with obesity differed substantially between the two cohorts. Recognizing factors associated with obesity in specific work settings may provide opportunities for optimizing preventive workplace interventions.

A job exposure matrix may be useful for the study of biomechanical workplace risk factors when individual-level exposure data are unavailable. We used job title-based exposure data from a public data source to construct a job exposure matrix and test exposure-response relationships with prevalent carpal tunnel syndrome (CTS). Exposures of repetitive motion and force from the Occupational Information Network were assigned to 3,452 active workers from several industries, enrolled between 2001 and 2008 from 6 studies. Repetitive motion and force exposures were combined into high/high, high/low, and low/low exposure groupings in each of 4 multivariable logistic regression models, adjusted for personal factors. Although force measures alone were not independent predictors of CTS in these data, strong associations between combined physical exposures of force and repetition and CTS were observed in all models. Consistent with previous literature, this report shows that workers with high force/high repetition jobs had the highest prevalence of CTS (odds ratio = 2.14-2.95) followed by intermediate values (odds ratio = 1.09-2.27) in mixed exposed jobs relative to the lowest exposed workers. This study supports the use of a general population job exposure matrix to estimate workplace physical exposures in epidemiologic studies of musculoskeletal disorders when measures of individual exposures are unavailable., (© The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)