Browsing by Author "Rosecrance, John, advisor"
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Item Open Access A comparison of wearable measurement systems for estimating trunk postures in manual material handling(Colorado State University. Libraries, 2017) Arroyo Vera, Jose Gustavo, author; Rosecrance, John, advisor; Gilkey, David, committee member; Reiser, Raoul, committee memberEpidemiologic studies have established that awkward trunk postures during manual materials handling are associated with an increased risk of developing occupational low back disorders. With recent advances in motion capture technology, emerging wearable measurement systems have been designed to quantify trunk postures for exposure assessments. Wearable measurement systems integrate portable microelectromechanical sensors, real-time processing algorithms, and large memory capacity to effectively quantify trunk postures. Wearable measurement systems have been available primarily as research tools, but are now quickly becoming accessible to health and safety professionals for industrial application. Although some of these systems can be highly complex and deter health and safety professionals from using them, other systems can serve as a simpler, more user-friendly alternative. These simple wearable measurement systems are designed to be less intricate, allowing health and safety professionals to be more willing to utilize them in occupational posture assessments. Unfortunately, concerns regarding the comparability and agreement between simple and complex wearable measurement systems for estimating trunk postures are yet to be fully addressed. Furthermore, application of wearable measurement systems has been affected by the lack of adaptability of sensor placement to work around obstructive equipment and bulky gear workers often wear on the job. The aims of the present study were to 1) compare the Bioharness™3, a simple wearable measurement system, to Xsens™, a complex wearable measurement system, for estimating trunk postures during simulated manual material handling tasks and 2) to explore the effects of Xsens sensor placement on assessing trunk postures. Thirty participants wore the two systems simultaneously during simulated tasks in the laboratory that involved reaching, lifting, lowering, and pushing a load for ten minutes. Results indicated that the Bioharness 3 and Xsens systems are comparable for strictly estimating trunk postures that involved flexion and extension of 30° or less. Although limited to a short range of trunk postures, the Bioharness also exhibited moderate to strong agreement and correlations with the Xsens system for measuring key metrics commonly used in exposure assessments, including amplitude probability distribution functions and percent time spent in specific trunk posture categories or bins. The Bioharness is suggested to be an a more intuitive alternative to the Xsens system for posture analysis, but industrial use of the device should be warranted in the context of the exposure assessment goals. In addition, a single motion sensor from the Xsens system placed on the sternum yielded comparable and consistent estimates to a sensor secured on the sternum relative to a motion sensor on the sacrum. Estimates included descriptive measures of trunk flexion and extension and percent time spent in specific trunk posture categories. Using one motion sensor instead of two may serve as an alternative for sensor placement configuration in situations where worker portable equipment or personal preference prevents preferred sensor placement.Item Open Access Analysis of 3D facial anthropometric measurements for respirator fit outcomes(Colorado State University. Libraries, 2023) Hobbs-Murphy, Kayna, author; Rosecrance, John, advisor; Brazile, Bill, committee member; Anderson, Brooke, committee member; Morris, Kristen, committee member; Hess, Ann, committee memberAnthropometry is central to the development of efficacious products and environments (i.e., personal protective equipment, clothing, sunglasses, chairs, interior spaces, etc.) used by humans. Three-dimensional (3D) scanning is increasingly common for collecting anthropometric data, as it is faster and less intrusive than traditional manual methods. Additionally, 3D anthropometric methods used to derive facial dimensions provide greater contextual application in the development of respirators and facemasks. More than 2,000 3D facial scans were analyzed to assess measurement reliability and the dimensions of 27 facial features. This research represents the largest sample of 3D facial anthropometrics assessed to date. The three specific aims of the research included: 1) to assess the intra- and inter-rater reliability of 3D facial measurement methods, 2) to compare the 3D facial anthropometric summary statistics from the present study to relevant summary statistics from manual facial measurements found in the literature, and 3) to assess the presence of differences in 3D facial anthropometrics related to respirator fit, based on demographic factors of gender, race/ethnicity, and age. Post hoc analyses were completed to quantify 3D facial measurement differences between demographic groups (within the larger demographic categories of gender, race/ethnicity, and age group). The most notable results of this research include a) high reliability in 3D measurement data collection methods, b) differences in measurement data summary statistics between 3D and manual methods, and c) significant differences in facial measurements between demographic categories of gender (Male and Female/Other), race/ethnicity (White, Black, LatinX, Asian, and Other), and age (18-34, 35-54, and 55-72).Item Open Access ATV mortality in the United States, 2011-2013(Colorado State University. Libraries, 2015) Lagerstrom, Elise, author; Gilkey, David, advisor; Rosecrance, John, advisor; Magzamen, Sheryl, committee member; Stallones, Lorann, committee memberThe purpose of this study is to examine contributing factors of ATV injuries and deaths through application of the Agent-Host-Environment epidemiological model. By analyzing the associations between contributing factors and classifying these factors based on the model, appropriate intervention strategies may be identified. All US incident reports of ATV fatalities and injuries between 2011 and 2013 were obtained from the Consumer Product Safety Commission (CPSC). Each report was read and coded based on information available in the narrative incident report. Each coded variable was classified as relating to a section of the epidemiologic triangle: agent, host, or environment. Descriptive statistics were obtained for the coded variables and Chi-Square Automatic Interaction Detector (CHAID) analysis was performed in order to identify associations between predictor variables. A total of 1,230 incident reports were obtained and, after data cleansing, a total 1,193 fatality reports remained. While only 12% of cases occurred on farms, the calculated incidence rate in the farming population (.62 per 100,000 population/year) is higher than the overall incident rate in the United States (.13 per 100,000 population/year). Descriptive statistics showed low helmet use (11.85% of fatal cases) and high use of alcohol and drugs (84.2% of fatal cases). The CHAID results showed significant associations between all types of variables: agent, host, and environment. The present study provides nationwide statistics on ATV fatalities, approaching risk factor analysis with regard to the agent-host-environment epidemiological model. The three aspects of the epidemiologic triangle each contribute, and build upon each other, to create the combination of risk factors that lead to a fatal event. By modeling and categorizing risk it is possible to develop targeted solutions to the root cause of the hazard. Through use of legislation and training, many host-related risk factors can be controlled, use of engineering controls can mitigate risk due to the agent and/or physical environment, and use of targeted marketing strategies and education may be able to limit risk due to the social environment.Item Open Access Characterizing stooped posture of agricultural tasks(Colorado State University. Libraries, 2024) Sanders, Denali, author; Rosecrance, John, advisor; Brazile, Bill, committee member; Hobbs-Murphy, Kayna, committee memberAgricultural field workers worldwide are often required to work in stooped postures during their working tasks. Stooped postures constitute a significant risk factor for the development of musculoskeletal disorders, specifically low back pathologies that cause pain. Chronic low back pain is a devastating disorder that can lead to depression, decreased mobility, lower quality of life, absenteeism from work, and decreased work productivity. Unfortunately, few studies have quantified stooped postures among agricultural workers, which makes it difficult to develop targeted work design improvements. The present study aimed to characterize stooped postures among workers engaged in several common agricultural tasks. Agricultural workers (N=43) were recruited from multiple Colorado farms and represented eight distinct work tasks. Participants wore a biomodule that contained a tri-axial accelerometer (Zephyr BioHarness) on their chests to record and log trunk postures in degrees for approximately two hours during specific work tasks. Data recorded on the sensor module were downloaded and analyzed in a customized RStudio program by participant and task to determine task cycle time, percentage of time spent in three posture categories (<0° to 30°, >30° to <60°, ≥60°), and mean trunk flexion. Stooped posture was defined as a trunk flexion equal to or greater than 60 degrees. The data indicated differences in task cycle time, percentage of time spent in posture categories, and mean trunk flexion across agricultural tasks. The results of the current study provide quantitative data that can help inform the development of targeted interventions aimed at reducing stooped postures in agricultural workers. Additionally, the methods developed in the present study may assist the Colorado Department of Agriculture and farm owners with evaluating the policies established in the Colorado Senate Bill (SB 21-087), which limits stooped postures during agricultural tasks that involve thinning and weeding during crop production.Item Open Access Direct assessment of upper limb muscle activity associated with dairy milking tasks through use of surface electromyography: an occupational research project(Colorado State University. Libraries, 2016) Mixco, Anthony, author; Rosecrance, John, advisor; Gilkey, David, advisor; Reiser, Raoul F., II, committee member; Tracy, Brian, committee member; Brazile, William, committee memberWork-related musculoskeletal disorders (WRMSDs) are an economic burden on employers across all industries. Within agriculture, a high prevalence of WRMSDs have been found among dairy workers (specifically those involved in milking tasks) in small and large-herd operations. However, the effects of milking activities in large-herd dairy operations have not been investigated with the direct physical exposure measures, such as surface electromyography (sEMG), necessary to best quantify occupational risk. The goal of the research reported in this dissertation was to fill that gap, using sEMG to better quantify upper-limb muscle activity among large-herd dairy workers and to compare the muscle activity across large and small-herd operations. Three studies were conducted to reach this goal. In the first, sEMG was used to detail activity of upper-limb muscles across all milking tasks in large-heard dairies. This study revealed that the biceps brachii have the most activity in overall milking work. In the second study, sEMG was used to examine the muscle activity associated with each of the five primary milking tasks: pre-dipping, stripping, wiping, milk cluster attachment, and post-dipping. This study revealed that wiping and milk cluster attachment tasks required the most muscle activity. Identification of these two tasks as the most strenuous provides the groundwork for future researchers to explore different ergonomic intervention methods for milking tasks in addition to milk cluster attachment. The third study compared the sEMG associated with milking activities at large-herd operations with those in small-herd dairies. The results revealed that although work pace and total tasks completed per milking shift differed from one size of dairy to the other, milking work was strenuous in both cases. The comparison of muscle activity associated with small-herd and large-herd milking activities establishes that interventions to alleviate exposure to ergonomic risk factors may potentially be used interchangeably. Future research should continue to analyze differences between small and large-herd dairy operations by examining the specific milking tasks in both settings.Item Open Access Inter-rater reliability of the hand activity level using cyclic and non-cyclic tasks(Colorado State University. Libraries, 2010) Gober, Jennifer, author; Rosecrance, John, advisor; Gilkey, David, committee member; Fitzhorn, Patrick, committee memberResearch has shown a link between exposure to excessive repetitive motion and the development of musculoskeletal disorders. Exposure assessment tools have been developed to measure risk factors, such as repetitive motion, and their relationship to health outcomes. To accurately evaluate risk factors, a tool must be both valid and reliable. The present study evaluated the inter-rater reliability of the Hand Activity Level (HAL), which is one portion of the ACGIH TLV for hand activity. Workers from a large appliance manufacturing facility were video recorded and assessed on a HAL rating scale by two independent raters. The HAL was originally designed to be used for tasks cyclic in nature, however, in the present study non-cyclic tasks were also rated. Work task HAL ratings were compared across raters using a weighted Pearson Product Moment Correlation Coefficient. Fair to moderate inter-rater reliability was found for both cyclic and non-cyclic tasks. A paired t-test was used to determine if there was a significant difference in correlation coefficients between HAL ratings for cyclic and noncyclic tasks. No significant difference was found between the correlation coefficients of cyclic and non-cyclic tasks. The present study found that the HAL is a reliable measure for both cyclic and non-cyclic tasks. Additional studies should be conducted to determine if the HAL is a valid measure of repetition in non-cyclic tasks.Item Open Access Intra-rater and inter-rater reliability of 3D facial measurements(Colorado State University. Libraries, 2023) Olmedo-Nockideneh, Isabel Rosalene, author; Rosecrance, John, advisor; Brazile, William, committee member; Gutilla, Margaret, committee memberThe purpose of this study was to assess the intra- and inter-rater reliability of a three-dimensional (3D) measurement system for determining the facial anthropometrics of 2,000 individuals. Intra-rater reliability is the degree of agreement among repeated administrations of a measurement system performed by a single rater and inter-rater reliability is the degree of agreement among independent raters who rate, code, or assess the same phenomenon using the same measurement system. Research studies that require the use of novel measurement systems by several raters must first establish that the phenomenon being measured have acceptable levels of both intra- and inter-rater reliability. Assessments of novel measurement systems are useful in refining the measurement tools given to raters by determining if a particular scale is appropriate for measuring a specific phenomenon. The present study was one facet of a larger anthropometric study of 2,000 facial scans, which investigates the demographic variables that may account for differences in facial size and shape. For this reliability study, a random sample of 30 facial scans was hand-digitized by four coders. The randomized sample was used to assess the intra- and inter-rater reliability of 28 facial anthropometric landmarks. The intraclass correlation coefficient was used to assess rater reliability. The results of the study indicated generally good inter-rater reliability and a steady improvement in both intra- and inter-rater reliability with greater experience. There are no conflicts of interest or a current funding source regarding this study. This study will impact environmental and occupational health by contributing a reliability study to my colleagues.Item Open Access Low back biomechanics during manual materials handling of beer kegs(Colorado State University. Libraries, 2017) Brents, Colleen, author; Rosecrance, John, advisor; Gilkey, David, committee member; Reiser, Raoul, committee memberBiomechanical risk factors such as heavy loads and awkward trunk postures have been associated with occupational low back pain. Those same risk factors are commonly experienced among workers handling beer kegs. The present study used a 3-dimensional motion capture system as a tool to investigate the low back biomechanics during keg handling at a working brewery. Specifically, five workers transferred spent kegs from a pallet to a conveyor to be cleaned and filled with beer in the present study. Data was collected during the portion of the shift workers handled kegs. Low back angular displacements were assessed during keg handling at two heights. Kegs originated from a high or low position and were defined as a high or low lift. Kinematic data from the study was used to estimate compressive and shear forces at the lumbosacral joint from a 2-dimensional static biomechanical model. Repeated measures analyses were performed with each low back angular displacement variable as a function of lift condition. Differences in low back biomechanics between high and low lifts were identified. During low lifts, torso flexion was significantly greater than high lifts. The magnitudes of flexion achieved during low lifts significantly exceeded those of high lifts. Differences between left axial rotation where significant with larger magnitudes of rotation occurring during high lifts. A broader range of angular displacements was observed in high lifts. In both lifting conditions, estimated kinetics exceeded recommended action limits, potentially putting workers at an increased risk for developing low back pain. Work design (lift condition) influenced low back motion during keg handling. Data collection during operational hours was feasible due to the portability and small design of inertial measurement units. Results from the study can help improve workplace design in a craft brewery, reduce risk, and create safer work.Item Open Access Managing through measurement: occupational health and safety in the construction industry(Colorado State University. Libraries, 2014) Schwatka, Natalie V., author; Rosecrance, John, advisor; Gilkey, David, committee member; Brazile, William, committee member; Henry, Kimberly, committee memberThe purpose of my dissertation was to describe five original research activities designed to characterize and enhance the health and safety of U.S. construction workers. The sequence of research activities illustrates my focus on occupational health and safety (OHS) measurement methods (i.e., lagging and leading measures), as well as an interest in translating this research into practical methods for industry stakeholders. First, I investigated a vulnerable sub-population of construction workers, the aging workforce, via a literature review and analysis of workers' compensation (WC) data. Through the results of these studies, I found that aging workers may have a different OHS experience than younger workers (e.g., greater lost work time costs), but the frequency and cost of injuries and illnesses was high regardless of worker age. Furthermore, in the cost regression models, the age of the claimant only accounted for a small amount of variance, which suggests that other factors influence the cost of a WC claim (e.g., organizational factors such as safety climate). Second, I investigated safety climate measurement methods, and translated prior safety climate research into an intervention for construction site supervisors. I demonstrated that safety climate could be measured via worker perceptions of top management, supervisor, and co-workers' response to safety on the job. Furthermore, a supervisor workshop focused on safety climate concepts could improve the safety participation behaviors of supervisors, and their crew members. Together, my findings demonstrate that both lagging and leading measures are valuable indicators of safety performance. Lagging measures such as WC data may serve as motivators for contractors to make decisions regarding safety. Leading measures such as safety climate and safety behaviors may also be useful, because we can use them to identify hazards and their associated risks before they result in serious negative outcomes. Since it was beyond the scope of my dissertation to measure both lagging and leading measures simultaneously, it is important for future research to evaluate the predictive validity of these measures of OHS.Item Open Access Musculoskeletal disorder symptom prevalence among construction workers(Colorado State University. Libraries, 2022) Townsend, Kelsey, author; Rosecrance, John, advisor; Brazile, Bill, committee member; Morris, Kristen, committee memberIntroduction: Musculoskeletal disorder (MSD) symptoms among construction workers have direct impact on their work ability and quality of life. Understanding self-reported MSD symptoms and their association with work tasks may assist in the identification of interventions to reduce their occurrence. The purpose of this descriptive study was to assess MSD symptom prevalence and job factors that may be associated with symptoms among a sample of 104 construction workers (plumbers and pipefitters) in the San Jose region of California. Methods: A self-administered survey, which was used with several other cohorts (including within construction trades) by a variety of investigators, was distributed to 104 plumbers and pipefitters at a local union meeting. The survey assessed demographic characteristics, work-related MSD symptom history in the previous 12-months and job factors which may contribute to MSD symptoms. Results: The mean age of the participating workers was 48. The top four body regions reported to have MSD symptoms were the low back, the shoulders, the neck, and the knees. Low back pain was associated with the job factor bending or twisting the back in an awkward way. Shoulder pain was associated with reaching or working overhead or away from the body. Neck pain was associated with working in cramped or awkward positions. Significance: Based on these analyses, a prioritization of resources that focus on the anatomical areas most likely to be injured as well as the job factors that contribute to the MSD symptoms in specific construction work may assist in injury prevention.Item Open Access Occupational injuries among craft brewery workers in Colorado(Colorado State University. Libraries, 2021) Brents, Colleen, author; Rosecrance, John, advisor; Brazile, William, committee member; Anderson, Brooke, committee member; Gibbons, Alyssa, committee member; Biegert, Jeff, committee memberWorkers at craft breweries in the U.S. are an understudied occupational cohort in a rapidly growing industry. Between 2015 and 2019, the number of craft breweries in Colorado grew 120% (Brewers Association, 2020). At the start of 2020, Colorado had more than 420 craft breweries with more than 9,100 workers. California is the only state with more craft breweries than Colorado. In the U.S., 8,000 craft breweries employed 161,000 workers (Brewers Association, 2020). As craft brewery workers produce beer through manufacturing processes, they are exposed to numerous occupational hazards that have been associated with injuries. These hazards include awkward body postures, lifting/carrying heavy loads, highly repetitive activities, sharp edges on materials and equipment, hot surfaces, and high levels of noise. According to national injury surveillance data, occupational injury rates are higher among brewery workers compared to all industries including private, state, and local government. Unfortunately, the national injury surveillance data do not differentiate between large and craft breweries. Craft breweries are substantially smaller than large industrialized breweries. An analysis of national injury data that includes all sizes of breweries may lead to erroneous perceptions of injuries affecting craft brewery workers. To date, no published studies have specifically outlined occupational hazards and injuries associated with craft brewing tasks. To effectively improve safety among craft brewery workers, it is critical that researchers and industry stakeholders have a better understanding of the occupational exposures related to injuries specific to craft brewery workers. The purpose of the present study was to characterize injuries specific to craft brewery workers and to identify their contributing factors in order to inform practitioners tasked with directing intervention resources. Researchers used data from workers' compensation to analyze injuries among Colorado craft brewery workers from 2013 to 2018. Researchers then analyzed accident narratives using the revised agent-host-environment epidemiologic model to better understand the relationship between the reported injury claim and the contributing factors to the agent, host, environment, and vehicle. Informal interviews with subject matter experts supplemented the workers' compensation analysis. Due to restrictions caused by the COVID-19 Pandemic, qualitative data were collected through virtual informal interviews with subject matter experts. Researchers developed a series of injury process models to highlight the relationship between injury characteristics and contributing factors that resulted in an injury nature. These models included information on how an injury nature was the result of an injury event when energy was transferred from the environment or vehicle to the injured workers' anatomical region. Researchers analyzed 570 claims. Results of the present study indicated that new workers experience occupational injuries, as more than 60% of claimants had less than two years of tenure at the time of injury. Among claims that incurred costs, the median total claim cost was $680 and the mean total claim cost was $2,100. Claims associated with sprains/strains incurred the highest costs per claim and the highest cumulative cost. Sprains/strains and contusions were the most frequent injury natures. The low back, hands, and fingers were the most frequently injured body parts. By analyzing accident narratives, researchers determined that injuries in craft breweries were typically associated with claimants either carrying items or performing cleaning tasks. The majority of injuries occurred in the packaging hall area of the craft brewery. Subject matter experts described how the packaging hall typically had the highest number of workers and the greatest proportion of new workers compared to other regions of the craft brewery. Contusions, lacerations, and burns affected the hands/fingers whereas sprains/strains predominately affected the low back. Sprains/strains and contusions both typically occurred in the packaging area of the craft brewery while the claimant carried an item. Lacerations typically occurred in the packaging area or kitchen. Burns typically occurred in the brewery or kitchen. Both burns and lacerations occurred while the worker performed maintenance work, cleaning activities, or food preparation tasks. Findings from this study (including the injury process models) can help guide practitioners tasked with developing interventions to reduce injuries and improve the quality of work life among craft brewery workers.Item Open Access Occupational injury prevention among loggers in the Intermountain region of the United States(Colorado State University. Libraries, 2018) Lagerstrom, Elise, author; Rosecrance, John, advisor; Magzamen, Sheryl, committee member; Brazile, William, committee member; Stallones, Lorann, committee memberDespite advances in harvesting techniques, commercial logging continues to be one of the most dangerous occupations in the United States (US). In 2015, logging workers had the highest rate of fatal work injuries of all US industries (Bureau of Labor Statistics, 2017). In 2016, the nationwide fatality rate for the logging industry was 100.1 per 100,000 full-time equivalent workers (FTE), almost 30 times higher than the nationwide fatality rate for all occupations combined (U.S. Bureau of Labor Statistics, 2017). Logging in the Intermountain (Montana and Idaho, USA) region is especially dangerous due to steep terrain, weather conditions, and remote work locations. To date, there are very few studies which provide an analysis of logging safety and none which focus on the specific challenges and risks present in the Intermountain region. The specific aims and objectives of this proposal are consistent with the recommended strategic goals outlined in the National Occupational Research Agenda (NORA). Strategic goals six and seven in the NORA are to reduce the number, rate and severity of traumatic injuries and deaths involving hazards of forestry and to improve the health and well-being of forestry workers by reducing occupational causes or contributing factors to acute and chronic illness and disease (NORA Agricultural Forestry and Fishing Sector Council, 2008). The Systematic Approach to Training provided the overall model for this project. Several other models and methodology were also used to create an intervention program focused on logging workers operating in the Intermountain region of the United States. The intervention program consisted of an emergency first-aid training program that provided didactic instruction, relevant examples, and practical skills to respond to emergencies, which commonly occur in the logging industry. The justification of the need for an emergency first-aid training program in the logging industry was primarily based mixed methods analysis of five-years of workers' compensation data and focus groups with 63 professional loggers (Study 1). We then investigated the demographics and self-reported work-related musculoskeletal symptoms among a cohort of 743 loggers in Montana (Study 2). We also conducted a study to quantify safety climate and identify the determinants of safety climate (Study 3). A Systematic Approach to Training was then used to develop, implement, and evaluate an emergency first-aid training program that specifically addresses the challenges and hazards of the logging industry (Study 4). Approximately 7-months following the emergency first-aid training a qualitative analysis was conducted to evaluate the longer-term effects of the training program and identify curriculum improvements (Study 5).Item Open Access Occupational physical activity in sedentary and active workers(Colorado State University. Libraries, 2017) Thompson, Janalee, author; Rosecrance, John, advisor; Anderson, Brooke, committee member; Crain, Tori, committee memberWith the increasing use of technology in the workplace, many jobs are becoming more sedentary. The purpose of this study was to establish a quantitative baseline measure of occupational physical activity (OPA) in active and sedentary workers. Two activity trackers (Fitbit Charge HR™ and Hexoskin) were used to assess activity measures (step count, heart rate and energy expenditure) among workers during their work shift. The first objective of the study was to assess the agreement between two types of accelerometer-based activity trackers as measures of OPA. The second objective of this study was to assess differences in measures of OPA among workers in physically active and sedentary work environments. There was a statistically significant difference in measures of total step counts between the two devices. When comparing active and sedentary workers there were also statistically significant differences in measures of step counts, mean percent heart rate increase, maximum heart rate range and energy expenditure. Conclusion: The Fitbit Charge HR™ and Hexoskin had significant differences in measures of step counts and heart rate. When comparing active and sedentary workers, there were significant differences in measures of step counts, mean heart rate, maximum heart rate range required by job, and energy expenditure. The results of the present study provide quantitative evidence that active workers require greater physiologic demands than sedentary workers.Item Open Access Prevalence of carpal tunnel syndrome among dairy parlor workers(Colorado State University. Libraries, 2011) Patil, Anuja, author; Rosecrance, John, advisor; Bachand, Annette, committee member; Gilkey, David, committee member; Greene, David, committee memberBACKGROUND The purpose of this study was to determine the prevalence of carpal tunnel syndrome (CTS) and median mononeuropathy among dairy workers. METHODS Sixty-six dairy parlor workers and 58 non-parlor workers at dairies in Texas, New Mexico and Colorado participated in structured interviews regarding hand symptoms and nerve conduction studies (NCS). A case definition of CTS was based on the presence of characteristic CTS symptoms and an abnormal median mononeuropathy. RESULTS The prevalence of CTS among the dairy parlor workers was 16.9% (n=11) and 3.6% (n=2) among non-parlor workers. The difference was found to be statistically significant (p<0.05) with an odds ratio of 5.3, CI (1.1-25.5). CONCLUSIONS Dairy parlor workers are exposed to highly repetitive and excessive hand and wrist postures combined with high muscle forces increasing the risk of developing CTS. Work tasks in dairy parlor need additional study to identify engineering as well as administrative controls to reduce CTS risk.Item Open Access Reference values of the distal sensory median and ulnar nerves among newly hired workers(Colorado State University. Libraries, 2021) Hischke, Molly, author; Rosecrance, John, advisor; Neophytou, Andreas, committee member; Anderson, Brooke, committee member; Gerr, Fredric, committee member; Reiser, Raoul F., II, committee memberCarpal tunnel syndrome (CTS) is the most common entrapment neuropathy in the upper extremity and more common among workers in industrial occupations than in the general population (Atroshi et al., 1999; Mattioli et al., 2009; Palmer, Harris, & Coggon, 2007). Because of the high prevalence of CTS in certain industries, some employers have implemented post-offer pre-placement screening programs using nerve conduction studies (NCS) to identify those at higher risk of developing CTS. NCS are commonly used to identify the median neuropathy characteristic of CTS by assessing the nerve conduction speed of the median nerve. There have been a number of retrospective and prospective cohort studies that have examined the relationship between NCS indicating median neuropathy among workers and the subsequent development of CTS (Werner et al., 2001; Franzblau et al., 2004; Gell et al., 2005; Silverstein et al., 2010; Dale et al., 2014). These studies have indicated that workers with NCS indicating median neuropathy across the carpal tunnel who were initially asymptomatic for CTS, eventually developed CTS at a statistically significant greater rate than workers with normal nerve studies. Some employers have used NCS to identify workers at higher risk of developing CTS and placing them into low hand-intensive work tasks to reduce the high prevalence of work-related CTS. To identify workers at higher risk, their NCS results are often compared to population-based reference values. However, many of these published reference values are limited by their small samples sizes and unsuitable statistical methodologies (Dillingham et al., 2016). Further, some researchers have questioned whether population-based reference values are representative of working populations, especially those in industries with a high prevalence of abnormal NCS (Dale, Gardner, Buckner-petty, Strickland, & Evanoff, 2016; Salerno et al., 1998). The purpose of this dissertation research was to (1) establish reference values for NCS outcomes of the distal upper extremity from a large sample (N=17,630) of newly hired manufacturing workers using novel statistical methods more appropriate for nerve conduction data, (2) investigate comorbid conditions associated with nerve conduction outcomes, and (3) determine the sensitivity and specificity of CTS symptoms for identifying workers with median mononeuropathy.