Respiratory-related workers' compensation claims from private employers - Ohio, 2001-2018.

BACKGROUND: Diseases and conditions related to the respiratory system contribute to work-related morbidity, mortality, and disability. Details on the causes and nature of work-related respiratory disease and the specific industries in which they occur are limited. This study identifies respiratory-related claims in the Ohio Bureau of Workers' Compensation (OHBWC) system and describes claim and worker characteristics to inform public health surveillance. METHODS: We developed a list of respiratory-related International Classification of Diseases Clinical Modification (ICD-CM) diagnosis codes and searched over 2 million claims filed between 2001 and 2018 in the OHBWC system for at least one of these codes. The claim characteristics, rates of claims by employer industry classification, and causes of claims from narrative text were determined for these respiratory-related claims. RESULTS: Among the 23,015 respiratory-related claims (5.8 per 10,000 full-time equivalents [FTE]), 54.6% had at least one ICD-CM code for Allergic Reactions and 30.6% had at least one code for Toxic Effects of Substances Chiefly Non-medicinal as to Source. Claim causes from narrative text included Chemical Exposure (30.3%), Activity Suggesting Exposure (24.4%), and Vapors, Gases, Dusts, or Fumes (VGDF) Exposure (19.3%). The highest overall rates of respiratory-related claims among private employers were for the agriculture, forestry & fishing (11.4 per 10,000), public safety (ambulance services) (11.3), and manufacturing (10.7) industry sectors. CONCLUSIONS: Respiratory-related claims in the OHBWC system were often acute in nature and included allergic reactions. Narratives from these claims provide insight into the work-related exposures and events causing claims or the disease and symptom factors surrounding claims.

Oil and Gas Extraction Industry Workers' Compensation Claims and Proposed Safety Interventions.

OBJECTIVE: This study analyzed Ohio workers' compensation data to identify potential prevention strategies for common oil and gas extraction industry claims. METHODS: Claim rates for 2001-2018 were calculated per full-time equivalent employee. Descriptive analyses on free-text descriptions of lost-time (LT) claims (>7 days away from work) identified common characteristics among claims and injured workers. RESULTS: Among 3134 claims, 860 (27%) were LT. The industry group, drilling contractors, experienced the highest LT claims rate, whereas the cost from servicing contractors was the highest. Contact with objects and equipment caused the highest LT claims rate. The most frequent LT occupation was roustabout, and the most frequent LT work activity was material handling. Transportation incidents caused most fatalities and hospitalizations. Over half of LT claims were from short-tenured workers. CONCLUSIONS: Both proven and innovative approaches are needed to reduce severe workers' compensation claims in this industry.

Construction industry workers' compensation injury claims due to slips, trips, and falls - Ohio, 2010-2017.

PROBLEM: Compared to other industries, construction workers have higher risks for serious fall injuries. This study describes the burden and circumstances surrounding injuries related to compensable slip, trip, and fall (STF) claims from private construction industries covered by the Ohio Bureau of Workers' Compensation. METHODS: STF injury claims in the Ohio construction industry from 2010-2017 were manually reviewed. Claims were classified as: slips or trips without a fall (STWOF), falls on the same level (FSL), falls to a lower level (FLL), and other. Claim narratives were categorized by work-related risk and contributing factors. Demographic, employer, and injury characteristics were examined by fall type and claim type (medical-only (MO, 0-7 days away from work, DAFW) or lost-time (LT, ≥8 DAFW)). Claim rates per 10,000 estimated full-time equivalent employees (FTEs) were calculated. RESULTS: 9,517 Ohio construction industry STF claims occurred during the 8-year period, with an average annual rate of 75 claims per 10,000 FTEs. The rate of STFs decreased by 37% from 2010 to 2017. About half of the claims were FLL (51%), 29% were FSL, 17% were STWOF, and 3% were "other." Nearly 40% of all STF claims were LT; mostly among males (96%). The top three contributing factors for STWOF and FSL were: slip/trip hazards, floor irregularities, and ice/snow; and ladders, vehicles, and stairs/steps for FLL. FLL injury rates per 10,000 FTE were highest in these industries: Foundation, Structure, and Building Exterior Contractors (52); Building Finishing Contractors (45); and Residential Building Construction (45). The highest rate of FLL LT claims occurred in the smallest firms, and the FLL rate decreased as construction firm size increased. Discussion and Practical Applications: STF rates declined over time, yet remain common, requiring prevention activities. Safety professionals should focus on contributing factors when developing prevention strategies, especially high-risk subsectors and small firms.

Work-Related Risk Factors for Rotator Cuff Syndrome in a Prospective Study of Manufacturing and Healthcare Workers.

OBJECTIVE: This prospective study assessed the risk of developing rotator cuff syndrome (RCS) with separate or specific combinations of biomechanical exposures measures, controlling for individual confounders. BACKGROUND: Compared with other musculoskeletal disorders, rates of work-related shoulder musculoskeletal disorders have been declining more slowly. METHOD: We conducted up to 2 years of individual, annual assessments of covariates, exposures, and health outcomes for 393 U.S. manufacturing and healthcare workers without RCS at baseline. Task-level biomechanical exposures assessed exposure to forceful exertions (level, exertion rates, duty cycles), vibration, and upper arm postures (flexion, abduction). Hazard ratios (HRs) were calculated with Cox proportional hazard models. RESULTS: We observed 39 incident RCS cases in 694 person-years (incidence rate = 5.62 per 100 person-years). Adjusting for confounders, we found increased risk of incident RCS associated with forceful hand exertions per minute for three upper arm posture tertiles: flexion ≥45° (≥28.2% time, HR = 1.11, CI [1.01, 1.22]), abduction ≥30° (11.9-21.2%-time, HR = 1.18, CI [1.04, 1.34]), and abduction >60° (≥4.8% time, HR = 1.16, CI [1.04, 1.29]). We failed to observe statistically significant effects for other interactions or any separate measures of biomechanical exposure. CONCLUSION: This study highlights the importance of assessing combinations of exposure to forceful repetition and upper arm elevation when developing interventions for preventing RCS. APPLICATION: Based on these results, interventions that reduce exposure to forceful repetition (i.e., lower force levels and/or slower exertion rates) may reduce the risk of RCS, especially when upper arm elevation cannot be avoided.

Comparison of the observer, single-frame video and computer vision hand activity levels.

Observer, manual single-frame video, and automated computer vision measures of the Hand Activity Level (HAL) were compared. HAL can be measured three ways: (1) observer rating (HALO), (2) calculated from single-frame multimedia video task analysis for measuring frequency (F) and duty cycle (D) (HALF), or (3) from automated computer vision (HALC). This study analysed videos collected from three prospective cohort studies to ascertain HALO, HALF, and HALC for 419 industrial videos. Although the differences for the three methods were relatively small on average (<1), they were statistically significant (p < .001). A difference between the HALC and HALF ratings within ±1 point on the HAL scale was the most consistent, where more than two thirds (68%) of all the cases were within that range and had a linear regression through the mean coefficient of 1.03 (R2 = 0.89). The results suggest that the computer vision methodology yields comparable results as single-frame video analysis.Practitioner summary: The ACGIH Hand Activity Level (HAL) was obtained for 419 industrial tasks using three methods: observation, calculated using single-frame video analysis and computer vision. The computer vision methodology produced results that were comparable to single-frame video analysis.

Occupational Injuries Among Construction Workers by Age and Related Economic Loss: Findings From Ohio Workers' Compensation, USA: 2007-2017.

Background: This study examined age-group differences in the rate, severity, and cost of injuries among construction workers to support evidence-based worker safety and health interventions in the construction industry. Methods: Ohio workers' compensation claims for construction workers were used to estimate claim rates and costs by age group. We analyzed claims data auto-coded into five event/exposure categories: transportation incidents; slips, trips, and falls (STFs); exposure to harmful substances and environments; contact with objects and equipment (COB); overexertion and bodily reaction. American Community Survey data were used to determine the percentage of workers in each age group. Results: From 2007-2017, among 72,416 accepted injury claims for ∼166,000 construction full-time equivalent (FTE) per year, nearly half were caused by COB, followed by STFs (20%) and overexertion (20%). Claim rates related to COB and exposure to harmful substances and environments were highest among those 18-24 years old, with claim rates of 313.5 and 25.9 per 10,000 FTE, respectively. STFs increased with age, with the highest claim rates for those 55-64 years old (94.2 claims per 10,000 FTE). Overexertion claim rates increased and then declined with age, with the highest claim rate for those 35-44 years old (87.3 per 10,000 FTE). While younger workers had higher injury rates, older workers had higher proportions of lost-time claims and higher costs per claim. The total cost per FTE was highest for those 45-54 years old ($1,122 per FTE). Conclusion: The variation in rates of injury types by age suggests that age-specific prevention strategies may be useful.

Workers' compensation claim counts and rates by injury event/exposure among state-insured private employers in Ohio, 2007-2017.

INTRODUCTION: This study analyzed workers' compensation (WC) claims among private employers insured by the Ohio state-based WC carrier to identify high-risk industries by detailed cause of injury. METHODS: A machine learning algorithm was used to code each claim by U.S. Bureau of Labor Statistics (BLS) event/exposure. The codes assigned to lost-time (LT) claims with lower algorithm probabilities of accurate classification or those LT claims with high costs were manually reviewed. WC data were linked with the state's unemployment insurance (UI) data to identify the employer's industry and number of employees. BLS data on hours worked per employee were used to estimate full-time equivalents (FTE) and calculate rates of WC claims per 100 FTE. RESULTS: 140,780 LT claims and 633,373 medical-only claims were analyzed. Although counts and rates of LT WC claims declined from 2007 to 2017, the shares of leading LT injury event/exposures remained largely unchanged. LT claims due to Overexertion and Bodily Reaction (33.0%) were most common, followed by Falls, Slips, and Trips (31.4%), Contact with Objects and Equipment (22.5%), Transportation Incidents (7.0%), Exposure to Harmful Substances or Environments (2.8%), Violence and Other Injuries by Persons or Animals (2.5%), and Fires and Explosions (0.4%). These findings are consistent with other reported data. The proportions of injury event/exposures varied by industry, and high-risk industries were identified. CONCLUSIONS: Injuries have been reduced, but prevention challenges remain in certain industries. Available evidence on intervention effectiveness was summarized and mapped to the analysis results to demonstrate how the results can guide prevention efforts. Practical Applications: Employers, safety/health practitioners, researchers, WC insurers, and bureaus can use these data and machine learning methods to understand industry differences in the level and mix of risks, as well as industry trends, and to tailor safety, health, and disability prevention services and research.

Workers' Compensation Claim Rates and Costs for Musculoskeletal Disorders Related to Overexertion Among Construction Workers - Ohio, 2007-2017.

Overexertion is a leading cause of work-related musculoskeletal disorders (WMSDs) among construction workers. Nearly 90% of construction jobs require manual handling of materials for approximately one half of the worker's time (1). In 2015, overexertion from lifting and lowering materials caused 30% of WMSDs among construction workers; overexertion involving pushing, pulling, holding, carrying, and catching materials caused an additional 37% of WMSDs (1). This study examined the rate and cost of WMSD claims from overexertion among Ohio construction workers during 2007-2017. Workers' compensation claims related to overexertion that were submitted to the Ohio Bureau of Worker's Compensation (OHBWC) by workers in the construction industry for injuries and illnesses occurring during 2007-2017 were analyzed. Rates and costs of allowed claims were measured by age group. Workers aged 35-44 years experienced the highest claim rate: 63 per 10,000 full-time employees (FTEs) for WMSDs from overexertion. However, claims by workers aged 45-54 years and 55-64 years were more costly on average and resulted in more days away from work. Ergonomic design improvements and interventions are needed to ensure that the majority of construction workers can safely perform jobs throughout their careers. Age-specific WMSD prevention and risk communication efforts also might be helpful.

Factors That Might Affect SARS-CoV-2 Transmission Among Foreign-Born and U.S.-Born Poultry Facility Workers - Maryland, May 2020.

Numerous recent assessments indicate that meat and poultry processing facility workers are at increased risk for infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (1-4). Physical proximity to other workers and shared equipment can facilitate disease transmission in these settings (2-4). The disproportionate number of foreign-born workers employed in meat and poultry processing reflects structural, social, and economic inequities that likely contribute to an increased COVID-19 incidence in this population* (5). In May 2020, the Maryland Department of Health and CDC investigated factors that might affect person-to-person SARS-CoV-2 transmission among persons who worked at two poultry processing facilities.† A survey administered to 359 workers identified differences in risk factors for SARS-CoV-2 infection between workers born outside the United States and U.S.-born workers. Compared with U.S.-born workers, foreign-born workers had higher odds of working in fixed locations on the production floor (odds ratio [OR] for cutup and packaging jobs = 4.8), of having shared commutes (OR = 1.9), and of living with other poultry workers (OR = 6.0). They had lower odds of participating in social gatherings (OR for visits to family = 0.2; OR for visits to friends = 0.4), and they visited fewer businesses in the week before the survey than did their U.S.-born coworkers. Some workplace risk factors can be mitigated through engineering and administrative controls focused on the production floor, and this will be of particular benefit to the foreign-born workers concentrated in these areas. Employers and health departments can also partner with local organizations to disseminate culturally and linguistically tailored messages about risk reduction behaviors in community settings, including shared transportation§ and household members dwelling in close quarters.¶.

Workers' compensation claims for traumatic brain injuries among private employers-Ohio, 2001-2011.

BACKGROUND: The purpose of this analysis was to identify and prioritize high-risk industry groups for traumatic brain injury (TBI) prevention efforts. METHODS: Workers with TBI from 2001 to 2011 were identified from the Ohio Bureau of Workers' Compensation data. To prioritize industry groups by claim type (lost-time (≥8 days away from work) and total claims) and injury event categories, we used a prevention index (PI) that averaged TBI counts and rate ranks (PI = (count rank + rate rank)/2). TBI rates per 10 000 estimated full-time equivalent (FTE = 2000 h/y) workers were calculated. RESULTS: From 2001 to 2011, 12 891 TBIs were identified among private employers, resulting in a rate of 5.1 TBIs per 10 000 FTEs. Of these, 40% (n = 5171) were lost-time TBIs, at a rate of 2.0 per 10 000 FTEs. Spectator Sports had the highest lost-time TBI rate (13.5 per 10 000 FTEs), whereas General Freight Trucking had the greatest number of lost-time TBIs (n = 293). Based on PIs, General Freight Trucking ranked first for lost-time TBIs for all injury events combined. Several industry groups within Construction, General and Specialized Freight Trucking, Services to Building and Dwellings, Employment Services, and Restaurants and Other Eating Places ranked high across multiple injury event categories for lost-time TBIs. CONCLUSIONS: The high-ranking industry groups identified from our study can be used to effectively direct occupational TBI prevention efforts.

Modeling the Effect of the 2018 Revised ACGIH® Hand Activity Threshold Limit Value® (TLV) at Reducing Risk for Carpal Tunnel Syndrome.

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.

Degree of Integration Between Occupational Safety and Health Programs and Wellness Programs: First-year Results From an Insurer-Sponsored Wellness Grant for Smaller Employers.

OBJECTIVE: The aim of this study was to describe levels of integration between occupational safety and health (OSH) and workplace wellness programs/practices/policies ("programs") among participants in an insurer-sponsored wellness grant program. METHODS: We analyzed survey responses about year 1 of an insurer-sponsored grant to start a wellness program from 220 small- and medium-sized employers. Responses yielded 25 indicators of OSH-wellness integration, and 10 additional indicators to summarize multiple responses. RESULTS: At least half of the employers (N = 220) reported some level of integration within five of seven categories of OSH-wellness integration. Employers sometimes considered ergonomics, safety, or substance exposure hazards while designing their wellness program (15%) or reduced such hazards to support their wellness program (24%). Few meaningful differences were observed by employer size. CONCLUSIONS: Although high levels of integration were unusual, some degree of integration was common for most indicator categories.

Workers' compensation injury claims among workers in the private ambulance services industry-Ohio, 2001-2011.

BACKGROUND: Ambulance service workers frequently transfer and transport patients. These tasks involve occupational injury risks such as heavy lifting, awkward postures, and frequent motor vehicle travel. METHODS: We examined Ohio workers' compensation injury claims among state-insured ambulance service workers working for private employers from 2001 to 2011. Injury claim counts and rates are presented by claim types, diagnoses, and injury events; only counts are available by worker characteristics. RESULTS: We analyzed a total of 5882 claims. The majority were medical-only (<8 days away from work). The overall injury claim rate for medical-only and lost-time cases was 12.1 per 100 full-time equivalents. Sprains and strains accounted for 60% of all injury claims. Overexertion from patient handling was the leading injury event, followed by motor vehicle roadway incidents. CONCLUSIONS: Study results can guide the development or improvement of injury prevention strategies. Focused efforts related to patient handling and vehicle incidents are needed.

Applying Machine Learning to Workers' Compensation Data to Identify Industry-Specific Ergonomic and Safety Prevention Priorities: Ohio, 2001 to 2011.

OBJECTIVE: This study leveraged a state workers' compensation claims database and machine learning techniques to target prevention efforts by injury causation and industry. METHODS: Injury causation auto-coding methods were developed to code more than 1.2 million Ohio Bureau of Workers' Compensation claims for this study. Industry groups were ranked for soft-tissue musculoskeletal claims that may have been preventable with biomechanical ergonomic (ERGO) or slip/trip/fall (STF) interventions. RESULTS: On the basis of the average of claim count and rate ranks for more than 200 industry groups, Skilled Nursing Facilities (ERGO) and General Freight Trucking (STF) were the highest risk for lost-time claims (>7 days). CONCLUSION: This study created a third, major causation-specific U.S. occupational injury surveillance system. These findings are being used to focus prevention resources on specific occupational injury types in specific industry groups, especially in Ohio. Other state bureaus or insurers may use similar methods.

Development of methods for using workers' compensation data for surveillance and prevention of occupational injuries among State-insured private employers in Ohio.

BACKGROUND: Workers' compensation (WC) claims data may be useful for identifying high-risk industries and developing prevention strategies. METHODS: WC claims data from private-industry employers insured by the Ohio state-based workers' compensation carrier from 2001 to 2011 were linked with the state's unemployment insurance (UI) data on the employer's industry and number of employees. National Labor Productivity and Costs survey data were used to adjust UI data and estimate full-time equivalents (FTE). Rates of WC claims per 100 FTE were computed and Poisson regression was used to evaluate differences in rates. RESULTS: Most industries showed substantial claim count and rate reductions from 2001 to 2008, followed by a leveling or slight increase in claim count and rate from 2009 to 2011. Despite reductions, there were industry groups that had consistently higher rates. CONCLUSION: WC claims data linked to employment data could be used to prioritize industries for injury research and prevention activities among State-insured private employers. Am. J. Ind. Med. 59:1087-1104, 2016. © 2016 Wiley Periodicals, Inc.

Mortality among styrene-exposed workers in the reinforced plastic boatbuilding industry.

BACKGROUND: We updated mortality through 2011 for 5203 boat-building workers potentially exposed to styrene, and analysed mortality among 1678 employed a year or more between 1959 and 1978. The a priori hypotheses: excess leukaemia and lymphoma would be found. METHODS: Standardised mortality ratios (SMRs) and 95% CIs and standardised rate ratios (SRRs) used Washington State rates and a person-years analysis programme, LTAS.NET. The SRR analysis compared outcomes among tertiles of estimated cumulative potential styrene exposure. RESULTS: Overall, 598 deaths (SMR=0.96, CI 0.89 to 1.04) included excess lung (SMR=1.23, CI 0.95 to 1.56) and ovarian cancer (SMR 3.08, CI 1.00 to 7.19), and chronic obstructive pulmonary disease (COPD) (SMR=1.15, CI 0.81 to 1.58). Among 580 workers with potential high-styrene exposure, COPD mortality increased 2-fold (SMR=2.02, CI 1.08 to 3.46). CONCLUSIONS: COPD was more pronounced among those with potential high-styrene exposure. However, no outcome was related to estimated cumulative styrene exposure, and there was no change when latency was taken into account. We found no excess leukaemia or lymphoma mortality. As in most occupational cohort studies, lack of information on lifestyle factors or other employment was a substantial limitation although we excluded from the analyses those (n=3525) who worked <1 year. Unanticipated excess ovarian cancer mortality could be a chance finding. Comparing subcohorts with potential high-styrene and low-styrene exposure, COPD mortality SRR was elevated while lung cancer SRR was not, suggesting that smoking was not the only cause for excess COPD mortality.

The effectiveness of insurer-supported safety and health engineering controls in reducing workers' compensation claims and costs.

BACKGROUND: This study evaluated the effectiveness of a program in which a workers' compensation (WC) insurer provided matching funds to insured employers to implement safety/health engineering controls. METHODS: Pre- and post-intervention WC metrics were compiled for the employees designated as affected by the interventions within 468 employers for interventions occurring from 2003 to 2009. Poisson, two-part, and linear regression models with repeated measures were used to evaluate differences in pre- and post-data, controlling for time trends independent of the interventions. RESULTS: For affected employees, total WC claim frequency rates (both medical-only and lost-time claims) decreased 66%, lost-time WC claim frequency rates decreased 78%, WC paid cost per employee decreased 81%, and WC geometric mean paid claim cost decreased 30% post-intervention. Reductions varied by employer size, specific industry, and intervention type. CONCLUSIONS: The insurer-supported safety/health engineering control program was effective in reducing WC claims and costs for affected employees.

Occupational injuries in Ohio wood product manufacturing: a descriptive analysis with emphasis on saw-related injuries and associated causes.

BACKGROUND: Stationary sawing machinery is often a basic tool in the wood product manufacturing industry and was the source for over 2,500 injury/illness events that resulted in days away from work in 2010. METHODS: We examined 9 years of workers' compensation claims for the state of Ohio in wood product manufacturing with specific attention to saw-related claims. For the study period, 8,547 claims were evaluated; from this group, 716 saw-related cases were examined. RESULTS: The sawmills and wood preservation sub-sector experienced a 71% reduction in average incidence rate and an 87% reduction in average lost-time incidence rate from 2001 to 2009. The top three injury category descriptions for lost-time incidents within saw-related claims were fracture (35.8%), open wounds (29.6%), and amputation (14.8%). CONCLUSIONS: For saw-related injuries, preventing blade contact remains important but securing the work piece to prevent kickback is also important.

A prospective study of musculoskeletal outcomes among manufacturing workers: I. Effects of physical risk factors.

OBJECTIVE: To better characterize associations between physical risk factors and upper-extremity musculoskeletal symptoms and disorders, a prospective epidemiologic study of 386 manufacturing workers was performed. BACKGROUND: Methodological limitations of previous studies have resulted in inconsistent associations. METHOD: An individual, task-based exposure assessment strategy was used to assess upper-extremity exertion intensity, repetition, and time-in-posture categories. Participants recorded time spent performing daily work tasks on a preprinted log, which was then used to calculate time-weighted-average exposures across each week of follow-up. In addition, a weekly Strain Index (SI) risk category was assigned to each participant. Incident musculoskeletal symptoms and disorders were assessed weekly. Proportional hazards analyses were used to examine associations between exposure measures and incident hand/arm and neck/shoulder symptoms and disorders. RESULTS: Incident symptoms and disorders were common (incident hand/arm symptoms = 58/100 person-years (PY), incident hand/arm disorders = 19/100 PY, incident neck/shoulder symptoms = 54/100 PY, incident neck/shoulder disorders = 14/100 PY). Few associations between separate estimates of physical exposure and hand/arm and neck/shoulder outcomes were observed. However, associations were observed between dichotomized SI risk category and incident hand/arm symptoms (hazard ratio [HR] = 1.73, 95% confidence interval [CI] = [0.99, 3.04]) and disorders (HR = 1.93,95% CI = [0.85,4.40]). CONCLUSION: Evidence of associations between physical risk factors and musculoskeletal outcome was strongest when exposure was estimated with the SI, in comparison to other metrics of exposure. APPLICATION: The results of this study provide evidence that physical exposures in the workplace contribute to musculoskeletal disorder incidence. Musculoskeletal disorder prevention efforts should include mitigation of these occupational risk factors.

Evaluation of alternate category structures for the Strain Index: an empirical analysis.

OBJECTIVE: The purpose of this study was to develop alternative Strain Index risk classification categories. BACKGROUND: Strain Index scores are usually categorized into four Strain Index "risk categories." The "original" risk categories were developed in the meat-packing industry and may not be fully applicable to other industries. METHOD: Daily Strain Index scores were estimated among 276 manufacturing workers participating in a cohort study of occupational risk factors for hand-arm musculoskeletal symptoms. Each score was categorized using the original method and a new method based on quartiles of Strain Index score values among symptomatic participants. Models examining associations between original Strain Index risk categories and incident hand-arm symptoms were compared to models examining associations between the alternative Strain Index risk categories and incident hand-arm symptoms. RESULTS: Compared to the respective referent categories, a twofold or greater increase in the risk of incident hand-arm symptoms was observed for the highest original Strain Index risk category (HR = 2.06, 95% CI = [1.08-3.92]) and for the second highest alternate Strain Index risk exposure category (HR = 2.21, 95% CI = [1.26-3.85]). Although significant associations between Strain Index risk category and incident hand-arm symptoms were observed for both Strain Index categorization methods, model fit statistics favored the alternate approach. CONCLUSION: Results from this study suggests that the Strain Index risk category structure may need to be tailored to specific populations. APPLICATION: If verified, results from this study provide a better way to identify hazardous manufacturing jobs and target them for exposure reduction.