Bert Stover

Early opioid prescription and subsequent disability among workers with back injuries: the Disability Risk Identification Study Cohort.

Study Design. Prospective, population-based cohort study. Objective. To examine whether prescription of opioids within 6 weeks of low back injury is associated with work disability at 1 year. Summary of Background Data. Factors related to early medical treatment have been little investigated as possible risk factors for development of long-term work disability among workers with back injuries. We have previously shown that about 1 of 3 of workers receive an opioid prescription early after a low back injury, and a recent study suggested that such prescriptions may increase risk for subsequent disability. Methods. We analyzed detailed data reflecting paid bills for opioids prescribed within 6 weeks of the first medical visit for a back injury among 1843 workers with lost work-time claims. Additional baseline measures included an injury severity rating from medical records, and demographic, psychosocial, pain, function, smoking, and alcohol measures from a worker survey conducted 18 days (median) after receipt of the back injury claim. Computerized database records of work disability 1 year after claim submission were obtained for the primary outcome measure. Results. Nearly 14% (254 of 1843) of the sample were receiving work disability compensation at 1 year. More than one-third of the workers (630 of 1843) received an opioid prescription within 6 weeks, and 50.7% of these (319 of 630) were received at the first medical visit. After adjustment for pain, function, injury severity, and other baseline covariates, receipt of opioids for more than 7 days (odds ratio = 2.2; 95% confidence interval, 1.5–3.1) and receipt of more than 1 opioid prescription were associated significantly with work disability at 1 year. Conclusion. Prescription of opioids for more than 7 days for workers with acute back injuries is a risk factor for long-term disability. Further research is needed to elucidate this association.

ISSLS Prize Winner: Early Predictors of Chronic Work Disability : A Prospective, Population-Based Study of Workers With Back Injuries

Study Design. Prospective population-based cohort study. Objective. To identify early predictors of chronic work disability after work-related back injury. Summary of Background Data. Identification of early predictors of prolonged disability after back injury could increase understanding concerning the development of chronic, disabling pain, and aid in secondary prevention. Few studies have examined predictors across multiple domains in a large, population-based sample. Methods. Workers (N = 1885) were interviewed 3 weeks (average) after submitting a lost work-time claim for a back injury. Sociodemographic, employment-related, pain and function, clinical, health care, administrative/legal, health behavior, and psychological domain variables were assessed via worker interviews, medical records, and administrative databases. Logistic regression analyses identified early predictors of work disability compensation 1 year after claim submission. Results. Significant baseline predictors of 1-year work disability in the final multidomain model were injury severity (rated from medical records), specialty of the first health care provider seen for the injury (obtained from administrative data), and worker-reported physical disability (Roland-Morris disability questionnaire), number of pain sites, “very hectic” job, no offer of a job accommodation (e.g., light duty), and previous injury involving a month or more off work. The model showed excellent ability to discriminate between workers who were/were not disabled at 1 year (area under the receiver operating characteristic curve = 0.88, 95% CI = 0.86–0.90). Conclusion. Among workers with new lost work-time back injury claims, risk factors for chronic disability include radiculopathy, substantial functional disability, and to a lesser extent, more widespread pain and previous injury with extended time off work. The roles of employers and health care providers also seem important, supporting the need to incorporate factors external to the worker in models of the development of chronic disability and in disability prevention efforts.

The Respiratory Effects of Volatile Organic Compounds

Abstract Volatile organic compounds (VOGs) have been implicated as causative agents in asthma and building-related illness. To determine whether a mixture of VOGs could impair lung function or cause airway inflammation among subjects without bronchial hyper responsiveness, the authors conducted a randomized, crossover-design trial of controlled human exposures to filtered air for four hours, VOCs at 25 mg/m3 for four hours, and VOGs at 50 mg/ m3 for four hours, using a VOG mixture based on sampling of indoor environments. VOG exposures caused dose-related increases in lower respiratory, upper respiratory, and non-respiratory symptoms, with no significant change in lung function (FEV1, FVC, or FEF25–75), nasal lavage cellularity or differential cell counts, induced sputum cellularity or differential cell counts, or biomarkers of airway inflammation, including IL-8, LTB4, or albumin in nasal lavage or induced sputum samples. Atopic individuals had significantly reduced FEE25–75 following exposure to VOCs at 50 mg/m3, suggesting that these individuals may be more sensitive to the health effects of VOCs. The authors conclude that reductions in levels of VOCs to substantially less than 25 mg/m3 are required if a “non-irritating” work environment is desired.

Predictors of Hearing Protection Use in Construction Workers

OBJECTIVES Although noise-induced hearing loss is completely preventable, it remains highly prevalent among construction workers. Hearing protection devices (HPDs) are commonly relied upon for exposure reduction in construction, but their use is complicated by intermittent and highly variable noise, inadequate industry support for hearing conservation, and lax regulatory enforcement. METHODS As part of an intervention study designed to promote HPD use in the construction industry, we enrolled a cohort of 268 construction workers from a variety of trades at eight sites and evaluated their use of HPDs at baseline. We measured HPD use with two instruments, a questionnaire survey and a validated combination of activity logs with simultaneous dosimetry measurements. With these measurements, we evaluated potential predictors of HPD use based on components of Penders revised health promotion model (HPM) and safety climate factors. RESULTS Observed full-shift equivalent noise levels were above recommended limits, with a mean of 89.8 +/- 4.9 dBA, and workers spent an average of 32.4 +/- 18.6% of time in each shift above 85 dBA. We observed a bimodal distribution of HPD use from the activity card/dosimetry measures, with nearly 80% of workers reporting either almost never or almost always using HPDs. Fair agreement (kappa = 0.38) was found between the survey and activity card/dosimetry HPD use measures. Logistic regression models identified site, trade, education level, years in construction, percent of shift in high noise, and five HPM components as important predictors of HPD use at the individual level. Site safety climate factors were also predictors at the group level. CONCLUSIONS Full-shift equivalent noise levels on the construction sites assessed were well above the level at which HPDs are required, but usage rates were quite low. Understanding and predicting HPD use differs by methods used to assess use (survey versus activity card/dosimetry). Site, trade, and the belief that wearing HPD is not time consuming were the only predictors of HPD use common to both measures on an individual level. At the group level, perceived support for site safety and HPD use proved to be predictive of HPD use.

10-Year prospective study of noise exposure and hearing damage among construction workers

Objectives To characterise the effects of noise exposure, including intermittent and peaky exposure, on hearing damage as assessed by standard pure-tone thresholds and otoacoustic emissions, a longitudinal study was conducted on newly hired construction apprentices and controls over a 10-year period. Methods Among the 456 subjects recruited at baseline, 316 had at least two (mean 4.6) examinations and were included in this analysis. Annual examinations included hearing threshold levels (HTLs) for air conducted pure tones and distortion product otoacoustic emission (DPOAE) amplitudes. Task-based occupational noise exposure levels and recreational exposures were estimated. Linear mixed models were fit for HTLs and DPOAEs at 3, 4 and 6 kHz in relation to time since baseline and average noise level since baseline, while controlling for hearing level at baseline and other risk factors. Results Estimated LEQ noise exposures were 87±3.6 dBA among the construction workers. Linear mixed modelling demonstrated significant exposure-related elevations in HTL of about 2–3 dB over a projected 10-year period at 3, 4 or 6 kHz for a 10 dB increase in exposure. The DPOAE models (using L1=40) predicted about 1 dB decrease in emission amplitude over 10 years for a 10 dB increase in exposure. Conclusions The study provides evidence of noise-induced damage at an average exposure level around the 85 dBA level. The predicted change in HTLs was somewhat higher than would be predicted by standard hearing loss models, after accounting for hearing loss at baseline. Limited evidence for an enhanced effect of high peak component noise was observed, and DPOAEs, although similarly affected, showed no advantage over standard hearing threshold evaluation in detecting effects of noise on the ear and hearing.

Tuberculosis in Health Care Settings and the Estimated Benefits of Engineering Controls and Respiratory Protection

Intra-institutional spread of tuberculosis (Tb) has re-emerged as a substantial public and occupational health threat. To characterize the person-hours and lifetime risks of Tb-related morbidity and mortality, we performed a risk assessment for health care workers (HCWs) developing Tb-related morbidity and mortality at varying levels of exposure, engineering controls, and respiratory protection. Under average conditions of exposure, one Tb skin-test conversion is estimated to occur for every 2650 person-hours of work by unprotected workers. With higher exposures, a skin-test conversion for an unprotected worker may occur in as few as 3 person-hours. Use of respiratory protection is estimated to reduce risks by the following proportions: surgical mask, 2.4-fold; disposable dust, fume, mist, or disposable high-efficiency particulate air filtering (HEPA) mask, 17.5-fold; elastomeric HEPA cartridge respirator, 45.5-fold; or powered air-purifying respirator (PAPR), 238-fold. Assuming a lifetime exposure of 250 hours, the risk of a skin-test conversion is estimated to be 9%. We conclude that HCWs are at substantial risk for Tb-related morbidity and mortality, and that administrative controls, engineering controls, and respirators offer substantial benefits in risk reduction.

Blood Manganese as an Exposure Biomarker: State of the Evidence

Despite evidence of adverse health effects resulting from exposure to manganese (Mn), biomarkers of exposure are poorly understood. To enhance understanding, mean blood Mn (MnB) and mean air Mn (MnA) were extracted from 63 exposure groups in 24 published papers, and the relationship was modeled using segmented regression. On a log/log scale, a positive association between MnA and MnB was observed among studies reporting MnA concentrations above about 10 μg/m3, although interpretation is limited by largely cross-sectional data, study design variability, and differences in exposure monitoring methods. Based on the results of the segmented regression, we hypothesize that below the concentration of about 10 μg/m3, Mn in the body is dominated by dietary Mn, and additional inhaled Mn only causes negligible changes in Mn levels unless the inhaled amount is substantial. However, stronger study designs are required to account for temporal characteristics of the MnA to MnB relationships that reflect the underlying physiology and toxicokinetics of Mn uptake and distribution. Thus, we present an inception cohort study design we have conducted among apprentice welders, and the analytical strengths this study design offers. To determine if blood could be a useful biomarker for Mn to be utilized by industrial hygienists in general industry requires additional time-specific analyses, which our inception cohort study design will allow.

Lobe of origin and histologic type of lung cancer associated with asbestos exposure in the Carotene and Retinol Efficacy Trial (CARET)

Lower lobe origin and histologic diagnosis of adenocarcinoma have been described as useful parameters for attributing lung cancer to prior asbestos exposure. To assess whether these characteristics differed between asbestos-exposed individuals and smokers, we evaluated lobe of origin and histologic type of tumors in 78 asbestos-exposed and 214 nonexposed heavy smokers developing lung cancer during the Carotene and Retinol Efficacy Trial (CARET), a prospective cancer chemoprevention trial. Most tumors in both cohorts, regardless of radiographic fibrosis at baseline, originated in upper lobes, representing 67% in asbestos-exposed and 80% in smokers, respectively (adjusted OR for lower lobe = 1.41; 95% CI = 0.69-2.91). Adenocarcinoma represented 32% of lung tumors in the asbestos cohort, and 30% in the smoking cohort (adjusted OR = 0.78; 95% CI = 0.40-1.55), and was inversely associated with radiographic fibrosis (adjusted OR = 0.19; 95% CI = 0.06-0.62). We conclude that neither anatomic site nor histologic cell type of tumors distinguishes effectively between smoking and asbestos as causal factors in development of lung cancer.

A multi-component intervention to promote hearing protector use among construction workers

Abstract Hearing protection devices (HPD) remain a primary method of prevention of noise-induced hearing loss despite their well-known limitations. A three-pronged intervention to increase HPD use was conducted among construction workers and included a baseline hearing loss prevention training, follow-up ‘toolbox’ (TB) reinforcement trainings, and use of a personal noise level indicator (NLI). A total of 176 subjects on eight sites completed three assessments. Prior to intervention, HPDs were used an average of 34.5% of the time and increased significantly, up about 12.1% after intervention and 7.5% two months after interventions were completed. The increase in HPD use was greatest among the group receiving both TB and NLI interventions; up about 25% from baseline, and this group was about two times more likely to use HPDs than the BL (baseline) training only group. This study demonstrates the mild impact of a well-constructed HPD use training and provides support for the additional use of a personal NLI to increase use of HPDs among construction workers. The most effective procedures for using such instruments require further exploration. Sumario Los instrumentos para la protección de la audición (HPD) siguen siendo el método primordial para la prevención de las pérdidas auditivas inducidas por ruido, a pesar de sus bien conocidas limitaciones. Se ha propiciado una intervención de tres facetas para incrementar el uso de los HPD por parte de los trabajadores de la construcción que incluyen un entrenamiento básico para la prevención de problemas auditivos, un conjunto de herramientas (TB) de seguimiento para reforzar los entrenamientos y el uso de un indicador personal de niveles de ruido (NLI). Completaron las tres evaluaciones un total de 176 sujetos en ocho sedes. Antes de la intervención, se usaron los HPD con un promedio de 34.5% del tiempo y aumentaron significativamente hasta alrededor del 12.1% después de la intervención y 7.5% dos meses después de que se completaron las intervenciones. El incremento en el uso de HPD fue mayor entre el grupo que recibió las intervenciones TB y NLI, hasta cerca del 25% a partir de la línea de base y este grupo fue usuario de HPD, cerca de dos veces más que el grupo que solo recibió el entrenamiento BL. Este estudio demuestra el ligero impacto de un entrenamiento bien estructurado del HPD y proporciona apoyo para el uso adicional de un NLI personal para incrementar el uso de HPDs en trabajadores de la construcción. Los procedimientos más efectivos para el uso de estos instrumentos, requiere un análisis adicional.

Crab allergen exposures aboard five crab-processing vessels.

Aerosolized crab allergens are suspected etiologic agents for asthma among crab-processing workers. The objectives of this study were to characterize crab allergen concentrations and respiratory symptom prevalence among processing workers aboard crab-processing vessels. A cross-sectional survey of five crab-processing vessels was conducted near Dutch Harbor, Alaska. Crab allergen concentrations were quantified during specific work activities with 25 personal air samples collected on polytetrafluoroethylene filters and analyzed by a competitive IgE immunoassay technique. Two standardized respiratory questionnaires were used to assess respiratory symptoms suggestive of bronchitis or asthma in 82 workers. Aerosolized crab allergen concentrations ranged from 79 ng/m3 to 21,093 ng/m3 (mean = 2797 ng/m3, SD = 4576 ng/m3). The highest concentrations were measured at butchering/degilling work stations, which were combined on the smallest vessel. A significant percentage of workers reported development of respiratory symptoms during the crab-processing season. Cough developed in 28% of workers, phlegm in 11% of workers, and wheeze and other asthma-like symptoms developed in 4% of workers. Despite variations in crab allergen levels, respiratory symptom prevalence was similar across all job categories. Substantial concentrations of crab allergen exposure were measured, as well as the potential for wide variability in exposure during crab processing aboard vessels. The high prevalence of reported respiratory symptoms across all job categories suggests potential adverse respiratory effects that should be further characterized by prospective studies using pulmonary function and serology testing, and rigorous exposure characterization.