Using job-title-based physical exposures from O*NET in an epidemiological study of carpal tunnel syndrome

OBJECTIVE: We studied associations between job title based measures of force and repetition and incident carpal tunnel syndrome (CTS). BACKGROUND: Job exposure matrices (JEMs) are not commonly used in studies of work-related upper extremity disorders. METHODS: We enrolled newly-hired workers into a prospective cohort study. We assigned a Standard Occupational Classification (SOC) code to each job held and extracted physical work exposure variables from the Occupational Information Network (O*NET). CTS case definition required both characteristic symptoms and abnormal median nerve conduction. RESULTS: 751 (67.8%) of 1107 workers completed follow-up evaluations. 31 subjects (4.4%) developed CTS during an average of 3.3 years of follow-up. Repetitive Motion, Static Strength, and Dynamic Strength from the most recent job held were all significant predictors of CTS when included individually as physical exposures in models adjusting for age, gender, and BMI. Similar results were found using time-weighted exposure across all jobs held during the study. Repetitive Motion, Static Strength, and Dynamic Strength were correlated, precluding meaningful analysis of their independent effects. CONCLUSION: This study found strong relationships between workplace physical exposures assessed via a JEM and CTS, after adjusting for age, gender, and BMI. Though job title based exposures are likely to result in significant exposure misclassification, they can be useful for large population studies where more precise exposure data are not available. APPLICATION: JEMs can be used as a measure of workplace physical exposures for some studies of musculoskeletal disorders

Ulnar Neuropathy Among Active Workers Based Upon Hand Diagram Ratings

BackgroundLimited studies have estimated the prevalence of ulnar neuropathy (UN) in the workplace. Hand diagrams have been demonstrated to have a good sensitivity and specificity when attempting to identify patients with UN.ObjectiveTo determine the prevalence and associated risk factors for UN among active workers based on results of a hand diagram, and to determine the reliability of hand diagram scoring.DesignCross‐sectional study.SettingSeven different industrial and clerical work sites.MethodsA total of 501 active workers were screened. Subjects completed a hand diagram and the Job Content Questionnaire, and had ergonomic assessment of their job. Each hand diagram was scored independently by 2 raters.Main Outcome MeasuresRating of the hand diagram for UN.ResultsInterrater reliability of scoring the hand diagram for UN was very high. The estimated prevalence of UN was 3.6%. Suspected UN was associated with positioning of the elbow but not by contact stress at the elbow or force at the hand. Smokers had a lower prevalence, but smokers with suspected UN had higher‐pack year histories. Workers with suspected UN had a greater sense of job insecurity and lower job satisfaction rating.ConclusionsHand diagram rating has a high interrater reliability. Suspected UN has a relatively high prevalence among active workers in comparison to prior estimates of the prevalence of UN among the general population and is not strongly associated with ergonomic factors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146927/1/pmr2571.pd

Asthma following household exposure to hydrofluoric acid

Background Almost all reports of respiratory health effects of hydrofluoric acid are derived from industrial settings and usually involved massive and conspicuous exposures. In the present report we describe a case of adult-onset asthma immediately following use of a household rust stain remover that contained an 8–9% aqueous solution of hydrofluoric acid (HF). Methods This is a case-report. A literature search of hydrogen fluoride, and reactive airways dysfunction syndrome (RADS) was performed. Results A previously healthy 26-year-old woman developed asthma immediately following inhalation exposure to hydrofluoric acid from a household cleaner, consistent with reactive airways dysfunction syndrome. The circumstances of exposure and possible mechanism of disease are discussed. Conclusions It is likely that this patient's use of the rust stain remover resulted in inhalation exposure to hydrofluoric acid well above any applicable standard, and hence constituted a ‘high level’ irritant exposure capable of inducing reactive airways dysfunction syndrome. In our opinion, the presence of this concentration hydrofluoric acid in a consumer product may be unduly hazardous. Am. J. Ind. Med. 44:321–324, 2003. © 2003 Wiley-Liss, IncPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34824/1/10274_ftp.pd

Use of hand diagrams in screening for ulnar neuropathy: Comparison with electrodiagnostic studies

Introduction: The objective of this study was to determine whether a hand diagram could be used to predict ulnar mononeuropathy. Methods: This was a prospective study of 117 consecutive patients referred for hand symptoms. Each subject filled out a hand diagram of symptoms and had median and ulnar sensory and motor nerve conduction studies, including ulnar conduction across the elbow. Results: The best model for predicting an ulnar mononeuropathy included hand diagram scores of definite or possible. The model had a sensitivity of 50% and specificity of 93% with an ROC area of 0.90. Conclusions: The ulnar hand diagram scoring system can be useful as a screening tool in the electrodiagnostic laboratory or for epidemiologic studies. Muscle Nerve, 2012Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94454/1/23452_ftp.pd

Chemical pneumonitis following household exposure to hydrofluoric acid

A previously healthy 26-year-old woman developed hemorrhagic alveolitis and adult respiratory distress syndrome (ARDS) following use of a hydrofluoric acid-containing household cleaning agent. Exposure was inhalational in nature. The circumstances and possible mechanism of chemical pneumonitis from low-dose inhalational exposure to hydrofluoric acid are discussed. Am. J. Ind. Med. 31:474–478, 1997. © 1997 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34814/1/15_ftp.pd

Natural history and predictors of long-term pain and function among workers with hand symptoms

OBJECTIVE: To evaluate predictors of hand symptoms and functional impairment after three years of follow-up among workers with different types of hand symptoms including carpal tunnel syndrome (CTS). Functional status and job limitations were also analyzed as key secondary objectives. DESIGN: Cohort design of 3-years duration SETTING: Working population-based study PARTICIPANTS: 1107 newly employed workers without a pre-existing diagnosis of CTS. Subjects were categorized into four groups at baseline examination: no hand symptoms, any hand symptoms but not CTS (recurring symptoms in hands, wrist or fingers without neuropathic symptoms), any hand symptoms of CTS (neuropathic symptoms in the fingers and normal nerve conduction study), or confirmed CTS (CTS symptoms and abnormal nerve conduction study). Among workers with hand pain at baseline, subject and job characteristics were assessed as prognostic factors for outcomes, using bivariate and multivariate regression models. INTERVENTIONS: Not applicable MAIN OUTCOME MEASURE: The primary outcome assessed by questionnaire at 3 years was “severe hand pain” in the past 30 days. RESULTS: At baseline, 155 workers (17.5% of 888 followed workers) reported hand symptoms, 21 had confirmed CTS. Presence of hand pain at baseline was a strong predictor of future hand pain and job impairment. Subjects with confirmed CTS at baseline were more likely to report severe hand pain, (adjusted prevalence ratios 1.98 [1.11 – 3.52]) and functional status impairment (adjusted prevalence ratios 3.37 [1.01 – 11.29]) than workers with other hand pain. Among subjects meeting our case definition for CTS at baseline, only 4 (19.1%) reported seeing a physician in the 3 year period. CONCLUSIONS: Hand symptoms persisted among many workers after 3 year follow-up, especially among those with CTS, yet few symptomatic workers had seen a physician

Time-resolved cutaneous absorption and permeation rates of methanol in human volunteers

This paper reports on an experimental study of dermal exposure to neat methanol in human volunteers for the purposes of estimating percutaneous absorption rates, permeation kinetics, baseline (pre-exposure) levels of methanol in blood, and inter- and intrasubject variability. A total of 12 volunteers (seven men and five women) were exposed to methanol via one hand for durations of 0 to 16 min in a total of 65 sessions, making this the largest controlled study of percutaneous absorption for this common solvent. In each session, 14 blood samples were collected sequentially and analyzed for methanol. These data were used to derive absorption rates and delivery kinetics using a two compartment model that accounts for elimination and pre-exposure levels. The pre-exposure methanol concentration in blood was 1.7 ± 0.9 mg l −1 , and subjects had statistically different mean concentrations. The maximum methanol concentration in blood was reached 1.9 ± 1.0 h after exposure. Delivery rates from skin into blood lagged exposure by 0.5 h, and methanol continued to enter the systemic circulation for 4 h following exposure. While in vitro studies have reported comparable lag times, the prolonged permeation or epidermal reservoir effect for such miscible solvents has not been previously measured. The mean derived absorption rate, 8.1 ± 3.7 mg cm −2  h −1 , is compatible with that found in the other in vivo study of methanol absorption. Both in vivo absorption rate estimates considerably exceed in vitro estimates. The maximum concentration of methanol in blood following an exposure to one hand lasting ∼20 min is comparable to that reached following inhalational exposures at a methanol concentration of 200 ppm, the threshold limit value-time weighted average (TLV-TWA). While variability in blood concentrations and absorption rates approached a factor of two, differences between individuals were not statistically significant. The derived absorption and permeation rates provide information regarding kinetics and absorbed dose that can help to interpret biological monitoring data and confirm mathematical models of chemical permeation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42237/1/420-70-5-341_70700341.pd

The relationship between body mass index and the diagnosis of carpal tunnel syndrome

Increased weignt and, more recently, body mass index (BMI), have been suggested as risk factors for carpal tunnel syndrome (CTS). In an effort to determine the relative risk (RR) of obesity in the development of CTS, 949 patients who had an evaluation of the right upper extremity that included motor and sensory conduction studies of the median and ulnar nerves were reviewed. Of these patients, 261 were diagnosed with a median mononeuropathy at the wrist. Those individuals who were classified as obese (BMI > 29) were 2.5 times more likely than slender individuals (BMI < 20) to be diagnosed with CTS. Forty-three percent of obese women and 32% of obese men had the diagnosis of CTS compared to 21% of slender women and 0% of slender men. © 1994 John Wiley & Sons, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50161/1/880170610_ftp.pd