School of Public Health

Permanent URI for this communityhttp://hdl.handle.net/1903/1633

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

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Now showing 1 - 10 of 994
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    FINANCIAL HARDSHIP, PSYCHOLOGICAL DISTRESS, AND RELATIONSHIP FUNCTIONING
    (2024) Chawla, Isha; Falconier, Mariana; Kim, Jinhee; Family Studies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This dissertation aimed to expand understanding of the impact of financial hardship on individual and relationship well-being within Black and Latinx populations during a time when these groups were facing disproportionately high economic challenges due to the COVID-19 pandemic. This goal was achieved through a comprehensive literature review and two empirical studies. The literature review highlighted the need for further research on the impact of financial hardship on psychological distress and relationship functioning in Black and Latinx during the COVID-19 pandemic. The literature review suggested that, although the link between financial hardship and psychological distress had been studied during the COVID-19 pandemic, research on potential moderating and mediating mechanisms, such as race-based trauma and social exclusion, remains unexplored.The first empirical study aimed to expand understanding of the association between pandemic related financial hardship and psychological distress, as proposed by the Family Stress Model (FSM; Conger et al., 1994), in Latinx and Black adults by examining potential mediating and moderating factors. Using the FSM framework, this study analyzed secondary data from non-Latinx Black (n = 355) and non-Black/non-White Latinx (n = 46) adults who completed the Maryland Pandemic Survey (UME, 2021) during the COVID-19 pandemic. The path analysis results showed a positive and significant relationship between pandemic related financial hardship and psychological distress. The study found a significant mediating role of pandemic related difficulty in accessing mental health care in the relationship between pandemic related financial hardship and psychological distress. Specifically, pandemic related financial hardship was positively associated with pandemic related difficulty accessing mental health care, which in turn, was positively linked to psychological distress. The second empirical study aimed to test FSM comprehensively by including all mediating mechanisms through which financial hardship may be associated with relationship dissatisfaction in both partners and to evaluate potential racial-ethnic differences by comparing Latinx and non-Latinx Black couples with non-Latinx White couples. Using baseline data from a federally funded relationship education program (collected between 2020 and 2023 during the COVID-19 period), the study conducted a path analysis to test the hypothesized relationships among heterosexual couples in which both partners identified as non-Latinx Black (n =167 couples), non-Black/non-White Latinx (n =78 couples), and non-White Latinx (n = 47 couples). Consistent with the FSM, results indicated a significant indirect positive relationship between each partner’s financial hardship and their hostility towards their partner, mediated by increases in their own psychological distress. Also consistent with FSM (Conger et al., 1994), there was an indirect positive relationship between each partner's psychological distress and their partner’s relationship dissatisfaction, mediated through increases in their own hostility towards their partner. In line with FSM’s hypothesized full pathways of influence, each partner’s financial hardship was positively and indirectly related to their partner’s relationship dissatisfaction (partner effect) through increases in their own psychological distress and hostility towards the other partner. Additionally, each partner’s financial hardship was indirectly related to their own relationship dissatisfaction (actor effect) through the same pathways of influence. The results highlight that financial hardship exacerbates psychological distress and relationship functioning, particularly among Black and Latinx populations. Barriers to mental health access and increased hostility within relationships were pivotal in linking financial hardship to adverse outcomes. These findings particularly emphasize the need for inclusive, culturally attuned support systems, as well as policy and programming efforts to mitigate the dual impacts of financial hardship on vulnerable communities during crises like the COVID-19 pandemic.
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    Gender Effects on Knee Loading and Prediction of Knee Loads Using Instrumented Insoles and Machine Learning
    (2024) Snyder, Samantha Jane; Miller, Ross H.; Shim, Jae Kun; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Women are more likely to experience knee osteoarthritis as compared to men, but the underlying mechanisms behind this disparity are unclear. Greater knee loads, knee adduction moment, knee flexion moment, and medial joint contact force, are linked to severity and progression of knee osteoarthritis. However, it is unknown if greater knee loads in healthy, young women during activities of daily living (sit-to-stand, stand-to-sit, walking and running) can partially explain the higher prevalence of knee osteoarthritis rates in women. Although previous research showed no significant differences in peak knee adduction moment and knee flexion moment between men and women, differences in peak medial joint contact force are largely unexplored. Women also tend to take shorter steps and run slower than men. It is unknown if these differences may result in greater cumulative knee loading per unit distance traveled as compared to men. Furthermore, knee loading measurement is typically confined to a gait laboratory, yet the knee is subjected to large cyclical loads throughout daily life. The combination of machine learning techniques and wearable sensors has been shown to improve accessibility of biomechanical measurements without compromising accuracy. Therefore, the goal of this dissertation is to develop a framework for measuring these risk factors using machine learning and novel instrumented insoles, and to investigate differences in peak and cumulative per unit distance traveled knee loads between young, healthy men and women. In study 1 we developed instrumented insoles and examined insole reliability and validity. In study 2, we estimated knee loads for most activities with strong correlation coefficients and low to moderate mean absolute errors. In study 3, we found peak medial joint contact force was not significantly different across activities for men and women. Similarly, in study 4, we found no significant difference between men and women in knee loads per unit distance traveled during walking and running. These findings suggest biomechanical mechanisms alone cannot explain the disproportionate rate of knee osteoarthritis in women. However, in future research, the developed knee loading prediction models can help quantify daily knee loads and aid in reducing knee osteoarthritis risk in both men and women.
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    Preventing Drowsy Driving in Young Adults Through Messaging Strategies that Influence Perceptions of Control and Risk
    (2024) Lee, Clark Johnson; Butler III, James; Beck, Kenneth H; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Drowsy driving is a serious health and safety problem in the United States: thousands of car crashes on U.S. roadways each year are attributed to this risky driving behavior. Although young drivers under the age of 26 years are especially at risk for being involved in drowsy driving car crashes, few anti-drowsy driving interventions targeting such drivers have been developed. Furthermore, most existing educational materials and interventions against drowsy driving have focused primarily on providing factual information about the dangers of drowsy driving and countermeasures against these dangers rather than on influencing beliefs and motivations underlying drowsy driving behavior, which may explain their apparent ineffectiveness at preventing drowsy driving behavior and resultant car crashes. Recent research indicates that messages targeting perceptions of control may be effective intervention strategies against drowsy driving behavior for young adult drivers by influencing their drowsy driving-related perceptions of risk, intentions, and willingness. This dissertation continues this line of research by pursuing two lines of inquiry. In Study #1, the efficacy of anti-drowsy driving messaging strategies designed to influence perceptions of control and risk related to drowsy driving behavior in reducing drowsy driving intentions, willingness, and behavior in a sample of young adult U.S. drivers between 18 and 25 years of age was evaluated through a randomized controlled trial. Study #1 sought to test the following hypotheses: Hypothesis 1: Participants exposed to interventional messaging strategies primarily aimed at lowering perceptions of control or heightening perceptions of risk related to drowsy driving report significantly less perceived control, greater perceived risk, less intentions, less willingness, and less behavior related to drowsy driving at 30-day post-intervention follow-up compared to participants exposed to messaging strategies providing only factual information about the dangers of drowsy driving; and Hypothesis 2: Participants exposed to interventional messaging strategies aimed at both lowering perceptions of control and heightening perceptions of risk related to drowsy driving report significantly less perceived control, greater perceived risk, less intentions, less willingness, and less behavior related to drowsy driving at 30-day post-intervention follow-up compared to participants exposed to messaging strategies providing only factual information about the dangers of drowsy driving, messaging strategies primarily aimed at lowering perceptions of control related to drowsy driving, or messaging strategies primarily aimed at heightening perceptions of risk related to drowsy driving. In Study #2, the relationships between perceived behavioral control, risk perception, intentions, willingness, and drowsy driving behavior in a sample of young adult U.S. drivers between 18 and 25 years of age were examined. Study #2 sought to test the following hypotheses: Hypothesis 3: The impact of interventional messaging strategies targeting drowsy driving perception of control on drowsy driving intentions, willingness, and behavior is mediated by drowsy driving risk perception such that messages lowering drowsy driving perceptions of control also heighten drowsy driving risk perception, which in turn decreases drowsy driving intentions, willingness, and behavior; Hypothesis 4: Interventional messaging strategies targeting drowsy driving-related perceptions of control or risk have a greater impact on drowsy driving willingness than on drowsy driving intentions; and Hypothesis 5: Drowsy driving willingness is a stronger predictor of drowsy driving behavior than is drowsy driving intentions. Study #1 provided supporting evidence of short-term cognitive effects but not short-term behavioral effects after exposure to messaging interventions designed to influence perceptions of control and risk related to drowsy driving behavior. Perceptions of risk were especially influenced by the messaging strategies examined, including those that provided only factual, knowledge-based information about drowsy driving. Study #2 provided supporting evidence that perceived behavioral control influenced drowsy driving intentions and drowsy driving willingness indirectly through perceptions of risk. Furthermore, willingness to drive drowsy was a stronger predictor of actual drowsy driving behavior than intentions to drive drowsy. The findings from these two studies should inform future research aimed at developing more effective messaging strategies against drowsy driving behavior in young adults.
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    DISPARITIES IN ADOLESCENT MENTAL HEALTH SERVICES UTILIZATION AND HELP-SEEKING
    (2024) Truong, Michelle L; Sehgal, Neil J; Boudreaux, Michel; Health Services Administration; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Inequities in access to and utilization of mental and behavioral health care for adolescents have persisted for numerous decades. Adolescents from racial and ethnic minority backgrounds, as well as those in underserved geographic regions, are disproportionately impacted. As the youth mental health crisis escalates, it is critical to study the mechanisms driving these disparities to inform effective and targeted interventions and policies. Divided into three studies, this dissertation explored the influence of individual, cultural, and contextual factors on adolescent help-seeking behaviors using data from the 2009 and 2011 to 2019 California Health Interview Survey (CHIS).The first study employed mediation analyses to assess the extent to which having a subjective or perceived need for mental health care, conditional on objective need, contributes to racial and ethnic disparities in mental health services utilization. I found significant racial and ethnic differences in subjective needs for mental health services and that these differences partially explain the racial and ethnic disparities in service utilization. The second study explored differences in mental health service utilization among subgroups of non-Hispanic (NH) Asian and Latino/Hispanic adolescents compared to NH white adolescents. I found that Vietnamese and Mexican adolescents were significantly less likely to utilize mental health services relative to their NH white counterparts. The third study merged the adolescent data with provider data from the National Plan and Provider Enumeration System (NPPES), facility data from the National Substance Use and Mental Health Services Survey (N-SUMHSS), and population data from the US Decennial Census Redistricting Data Summary Files to assess the moderating effects of distance to the nearest pediatric mental health facility and provider-to-population densities on the relationship between subjective mental health care needs and service utilization. I discovered that provider density and subjective needs interact, resulting in a diminished effect of subjective needs on service utilization among adolescents residing in areas with lower primary care provider density. I did not find that distance to the nearest pediatric mental health facility had a significant impact on service utilization. This dissertation examined racial, ethnic, and geographic mental health care disparities among a diverse adolescent population in California. Findings from this work contribute to the understanding of adolescent help-seeking behaviors and provide insights for targeted interventions and policies to advance mental health care equity.
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    P(L)AYING FOR THE FUTURE: THE COALESCING OF YOUTH, SPORT, AND COMMUNITY DEVELOPMENT IN CHARM CITY
    (2024) Stone, Eric Alexander; Andrews, David L; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This project explores how Sport-Based Youth Development (SBYD) has been arrived at as an ideal vehicle for youth development in contemporary Baltimore. To understand the SBYD approach, the project seeks to explore four interrelated empirically grounded sites/questions that explain why sport is expected to help develop, discipline, and prepare youth and communities for the future. Three key themes emerged from this work: 1) that youth must be problematized by different ideas, beliefs, and discourses to make them ‘amenable’ to being targets of SBYD; 2) that organizations are pushed into competing with one another rather than collaborating due to the need of the state to maintain control of how youth are incorporated into society; and 3) that various tools and techniques are used through the vehicle of sport to inculcate specific values into underserved youth and their communities. The first chapter identifies two of the key theoretical positions/approaches that inform the project: Governmentality and Articulation as theory/method. The second chapter provides an overview of how scholars have examined the phenomenon of Sport for Development and Peace as a historical, methodological, and empirical site. The third chapter identifies the methods and methodologies that underpin the project. The fourth chapter provides a brief reflexive overview of how I arrived in Baltimore to conduct the project. The fifth chapter seeks to (explore) how Baltimore’s underserved citizens have been positioned as targets of SBYD as conceived of by politicians, providers, public servants, and citizens of the city, state, and nation. The project found that SBYD in Baltimore is a product of specific policies, processes, decisions, ideologies, and discourses that conspire to create a specific understanding of youth and communities as ripe for and requiring intervention through sport and other recreational pursuits to reform their behavior and orientation towards neoliberal social values that has evolved over the last fifty years. The sixth chapter examines/explicates how discourses of youth, their future, and the role of sport are used by three SBYD organizations to connect with potential participants, to obtain resources and funding, and to report on their activities and programming to measure the impact on the targeted community. The project found that underserved youth and communities are subjectivated by discourses of responsibility, deficiency, the unknown future, and the perceived American values of neoliberal meritocracy. These discourses were conveyed by programs via their websites, curricula, tax documents, and other forms of media to funders, participants and other valueholders. The seventh chapter identifies how organizations make use of formal and informal relationships to support the implementation of programming, to obtain funding, and to support organizations as they seek to legitimize their operations and activities in the eyes of valueholders. The project found that the use of formal and informal relationships by valueholders and organizations enables SBYD providers to secure access to funding, space, and capacity to support program initiatives. The eighth chapter seeks to engage with the beliefs, perspectives, and values of SBYD providers and valueholders to understand how these personal ideas and views shape the implementation of SBYD in Baltimore by speaking to the staff of three organizations operating within the city. The project found that the production of SBYD programming is facilitated and challenged by perceptions of the youth and community, ideas about the purpose and value of sport, and a broader rooting of ideas about youth and communities in urban stereotypes. By examining these four sites/questions, the project identifies how SBYD is assembled into a disciplining, educating, rationalizing tool to create productive youth for the future. The project ends by identifying new areas of research such as education initiatives for volunteers to contextualize the communities they work in, challenges and limitations such as completing research during the COVID-19 Pandemic, and key takeaways such as connecting with youth to move away from abstract stereotypes of urban life.
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    EXPLORING ENVIRONMENTAL INJUSTICE AND AIR POLLUTION-RELATED HEALTH EFFECTS IN PRINCE GEORGE'S COUNTY, MARYLAND
    (2024) Ravichandran, Vivek; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Polluting facilities have been historically sited in disadvantaged communities of color, known as environmental justice (EJ) communities, due to limited perceived community resistance and mobilization. There is a plethora of air quality disparity research but a gap persists in ascertaining the health inequities associated with community exposure to air pollutants, such as particulate matter (PM) and black carbon (BC), at the neighborhood resolution. To address this gap in EJ science, this dissertation has four specific aims: (1) Implement the community-based participatory research (CBPR) framework to expand and enhance the community-engaged infrastructure to ensure the success of Aims 2-4; (2) Identify spatiotemporal pollution patterns across the Route 50-Sheriff Road-Kenilworth Ave Quadrant; (3) Determine short-term health impacts associated with community exposure to PM and BC via a panel study involving pulse oximeters to correlate elevated PM and BC levels to blood oxygen saturation (SpO2 levels); and (4) Conduct semi-structured interviews and use NVivo to perform thematic analysis on barriers and motivating factors towards passing EJ legislation. My findings demonstrated that a more diverse and representative community advisory board (CAB) allowed us to successfully conduct research while maintaining trust within the community, and bringing in voices from various demographic groups, including different ethnicities, ages, income levels, and geographic locations. This led to a more comprehensive understanding of the community's concerns, priorities, and needs related to air quality. Additionally, my findings revealed that both PM and BC levels were elevated during morning rush periods. PM levels did not exceed the Environmental Protection Agency (EPA) annual standards, but did exceed the more protective World Health Organization (WHO) guidelines. Robert Gray Elementary School exhibited higher PM levels than the other Quadrant sites. Furthermore, BC levels at Fairmount Heights High School were above the threshold defined in the literature above which cognitive inhibition and poor respiratory outcomes have been observed, highlighting the effect of air pollution exposure on vulnerable life stages in the Quadrant. BC peaks were also observed 10-15x these unofficial health-based thresholds. Using a pulse oximetry panel study, we found previous and concurrent day lagged fine particulate matter (PM2.5) was weakly associated with reductions in SpO2. Using NVivo, we identified 18 parent codes and 27 subcategories from our semi-structured interviews with Maryland policymakers/agency staff. Key barriers were: (1) the lack of strategic EJ plans; (2) limited community engagement particularly from those living in communities impacted by environmental injustice; and (3) interagency and policymaker collaboration exacerbated by a clear partisan divide. These findings provide evidence of previous misclassified exposure assessments from sparse existing regulatory monitors, present strategies for overcoming EJ barriers in the state, and underscore the importance of collaboration, community engagement, and policy reform to address environmental disparities and promote environmental justice.
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    THE INFLUENCE OF CUMULATIVE SLEEP RESTRICTION ON HUMAN PERFORMANCE: EXAMINATION OF BRAIN DYNAMICS AND SUSTAINED ATTENTION
    (2024) Kahl, Steven; Hatfield, Bradley; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Sustained attention (SA) impacts nearly every aspect of human performance. From the exactness of performing brain surgery to safely driving from one location to another, the ability to concentrate on a task for a period of time is important for success in work, school, relationships, and individual activities. As a key component of executive function (EF) and psychomotor performance, SA can be affected by many mental and physical processes. One process that can impact SA is restricted sleep, which is becoming more relevant in our ever-evolving technological society. Numerous studies have examined the impact of short bouts of restricted sleep on response time, a measure of SA, but few studies have examined the impact of the accumulating effect of sleep restriction (SR) on response time and brain dynamics as measured with electroencephalography (EEG). As part of a larger 40-day study, eight healthy participants (five female, average age 27.75) were observed for seven consecutive days and nights in a sleep lab, where they spent five hours in bed per night and engaged in numerous psychomotor vigilance tests (PVT), an indicator of SA, as part of their daytime activities. Through multiple one-factor ANOVAs, response time significantly slowed, and brain dynamic changes occurred, measured by slow wave activity (SWA) maxima change in the Fz electrode, located in the midline frontal region, over the course of the entire week of continual SR compared to an extended sleep night. Employing mixed method effects revealed a statistically significant relationship between response time and SWA maxima differences. The data show that not only does response time increase the day after rising first and last SWA maxima levels converge (i.e., flattening of the line slope connecting these values) caused by short bouts of SR, but these phenomena continue this progression with prolonged SR. Over the course of the week-long SR, the final SWA maximum increased at a higher rate than the first SWA maximum, leading to the maxima difference shrinking as response time increases. These findings indicate that brain dynamics highlight less restorative sleep occurring alongside a lack of sustained attention when sleep is restricted on a consistent basis.
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    THE RELATIONSHIP OF PERCEIVED WORKLOAD AND PSYCHOMOTOR PERFORMANCE TO BRAIN DYNAMICS DURING VARYING DEGREES OF TASK DEMAND AND CONTROLLABILITY IN A FLIGHT-RELATED COMPENSATORY TRACKING TASK
    (2024) Pietro, Kyle; Hatfield, Bradley D.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The assessment and prediction of cognitive-motor performance holds great importance for any discipline connected to human operators in the context of safety-critical behavior. A study of mental workload is essential to understanding the intrinsic limitations of the human information processing system, and the resultant cognitive-motor behavior. Mental workload and the quality of cognitive-motor performance are generally known to be impacted by task demand. However, one feature of task demand far less understood is the controllability of a system (e.g. the responsiveness of a flight platform and its handling qualities). In the realm of Human-Machine Interface, the assessment of system controllability has typically been conducted through subjective measurements, such as the Cooper-Harper Rating Scale, a widely used metric in aircraft design to measure perceived operator workload and handling qualities, first proposed in 1969. A fundamental element of the decision making process for handling qualities associated with operator workload includes the reporting of the control compensation required to overcome deficiencies and errors that could impact and inhibit the successful completion of a task. Yet, the Cooper-Harper Rating Scale, and all other subjective rating scales are limited by a lack of objectivity, reliability, reduced sensitivity to dynamic changes in operator workload, and, are solely dependent on subjective estimates of effort to control compensation within a system, despite such wide usage in the field. To overcome such limitations, the contribution of this dissertation is the estimation of perceived operator workload, based on objective brain dynamics captured during varying levels of task demand and controllability. Therefore, the objective of this dissertation was to ascertain how objective brain dynamics and subjective ratings would respond to flight-related compensatory tracking tasks when handling qualities and task demand are manipulated. More specifically, this dissertation assessed the relationship between objective brain dynamics and subjective rating scales explicitly related to mental workload, as reported during compensatory tracking tasks of varying complexity, while also challenged with progressively increasing levels of controllability (i.e., levels of handling qualities). Thus, Aim 1 was to assess the effects of varying levels of handling qualities (i.e., HQR1, HQR2, HQR3) on mental workload and psychomotor performance. Aim 2 was to investigate the effects of increased task demand (i.e., Single-axis vs. Multi-axis) on mental workload and psychomotor performance. Finally, Aim 3 was to examine the empirical relationship between objective brain dynamics and subjective ratings of workload. Accordingly, this dissertation employed a 2 Condition (Single-axis vs. Multi-axis) x 3 Level of Handling Qualities (HQR1, HQR2, HQR3) design. Perceived workload, psychomotor performance, and brain dynamics, derived from EEG power spectra and spectro-temporal analyses, were assessed in twenty-two volunteer participants in the Naval Reserve Officers’ Training Corps. Overall, the findings of this dissertation support a characterization of the human information processing system as a finite resource with a limited capacity. When challenged with increasing levels of handling qualities, parietal alpha power decreased, behavioral performance was significantly attenuated, and subjective ratings of workload were higher, as was expected. Accordingly, there was a significant relationship between objective brain dynamics and subjective ratings of workload. Furthermore, an exploratory wavelet-based analysis revealed some generally high cross-correlations between brain dynamics and psychomotor performance, which may inform future research efforts of more dynamic measurement strategies to capture perceived workload with increased fidelity. Therefore, the results of this dissertation underscore the usage of objective brain dynamics to supplement subjective rating scales, which can provide additional insights to enhance our understanding of brain and motor coordination under varying levels of task demand and system handling qualities.
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    ENVIRONMENTAL EXPOSURES AND CHILDREN’S HEALTH
    (2024) Crnosija, Natalie; Payne-Sturges, Devon C.; Puett, Robin C.; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Climate change-driven physicochemical exposures, like extreme heat, wildfire and hurricanes are increasingly being investigated in the public health literature for their potential association with health outcomes. It is important to investigate children’s health specifically in the context of the exposures, as children’s physiological immaturity can make them uniquely vulnerable to these stressors because of their limited adaptive capacity. This dissertation investigates three distinct epidemiologic questions within this sphere, examining: 1) whether Extreme Heat Event Exposure associates with Kindergarteners’ Reading and Mathematics Performance, 2) whether wildfire smoke exposure affects respiratory/cardiovascular pediatric inpatient hospitalization in Alaska, 2015-2019, and 3) the association between exposure to Hurricane Irma and Internalizing, Externalizing and Total Problem Behaviors Among South Floridian Adolescents. Data for each of these studies was obtained from different sources, including the Early Childhood Longitudinal Study—Birth Cohort, hospital administrative data from the Alaska Department of Health and the NIH’s Adolescent Brain Cognitive Development Study. Where appropriate, external data was linked to these datasets as a means of linking exposures to health outcome data. In the first study, we found weak evidence of an association between exposure to lagged extreme heat events and children’s performance on kindergarteners’ mathematics and reading performance. In the second study, we observed a number of nonsignificant, minor associations between wildfire smoke exposure and respiratory and cardiovascular inpatient hospitalization among Alaskan children. In the third study, we observed a number of nonsignificant, minor associations between exposure to Hurricane Irma and internalizing, externalizing and total problem behaviors using data from Baseline and Wave 2 of the ABCD study. In summary, this research indicates the need for larger, more robust samples to investigate children’s health outcomes.
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    THE EFFECTS OF AGE, SARCOPENIA, AND RESISTANCE EXERCISE TRAINING ON MITOCHONDRIAL STRUCTURAL DYNAMICS IN SKELETAL MUSCLE
    (2024) Sapp, Catherine; Prior, Steven J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Sarcopenia, the progressive, age-related loss of skeletal muscle mass, contributes to older adults’ risk of falls, hospitalization, and loss of independence. Mitochondrial dysfunction is a hallmark trait of aging and sarcopenia that may be mediated by changes to mitochondrial structure and location through the involvement of mitochondrial fusion, fission, and mitophagy (collectively referred to as mitochondrial quality control). Therefore, the purpose of this dissertation was to investigate whether mitochondrial quality control is altered by age or sarcopenia. The first study performed in a rat model of aging demonstrated that expression of proteins regulating fusion and mitophagy was higher in skeletal and cardiac muscle from old vs. young rats, and this was accompanied by reduced expression of fission proteins in skeletal muscle in the old rats. The second study included older humans and revealed no differences in mitochondrial quality control protein expression in skeletal muscle from sarcopenic vs. non-sarcopenic older adults. Furthermore, twelve weeks of resistance exercise training did not alter the expression of mitochondrial quality control proteins in the sarcopenic individuals. The third study investigated morphological differences in mitochondrial subpopulations and lipid droplets from the sarcopenic individuals from study two, both before and after resistance exercise training. Peripherally located and intermyofibrillar mitochondrial content and morphology did not change significantly after resistance exercise training. Lipid droplets from the intermyofibrillar region were similarly unchanged, but lipid droplets from the peripheral region had minor morphological changes after resistance exercise training. Together, this dissertation indicates that mitochondrial quality control proteins in skeletal and cardiac muscle are altered in response to aging and may contribute to mitochondrial dysfunction, but mitochondrial structural dynamics in skeletal muscle do not appear to be altered in older adults with a moderate degree of sarcopenia. This suggests that other, non-mitochondrial factors may play larger roles in the pathophysiology of sarcopenia. While the sarcopenic participants did improve muscular strength after resistance training, this was not accompanied by changes in mitochondrial content, morphology, or quality control. Therefore, resistance exercise training may not be an effective strategy to enhance mitochondrial structural dynamics in sarcopenia.