UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
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Item RACIAL AND ETHNIC DISPARITIES OF BREAST CANCER RISK: THE ROLE OF INDIVIDUAL AND NEIGHBORHOOD-LEVEL CARDIOMETABOLIC FACTORS(2023) Ogbenna, Bethany Townsend; Dallal, Cher; Epidemiology and Biostatistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: Observed racial and ethnic disparities in breast cancer are complex, in part, due to biological and behavioral factors at the individual and neighborhood level. Cardiometabolic factors such as the use of cholesterol-lowering drugs and engaging in healthy lifestyle behaviors may reduce breast cancer risk, however, the current understanding of these factors among diverse racial and ethnic populations remains limited. Moreover, at the neighborhood-level, the extent to which neighborhood socioeconomic status (nSES) influences inflammatory profiles among racially and ethnically diverse populations remains unclear. Using data from the Multiethnic Cohort Study (MEC), this dissertation investigates cholesterol-lowering drug use (Aim I) and a Healthy Lifestyle Index (HLI) (Aim II) in relation to postmenopausal breast cancer risk by race and ethnicity; and, assesses associations between nSES and inflammatory biomarkers among adults (Aim III). Methods: Prospective cohort analyses were conducted among postmenopausal women who completed the third MEC follow-up questionnaire in 2003 (Aim 1, n=41,394) or the baseline questionnaire in 1993-1996 (Aim 2, n=65,561) and were followed until 2017 for invasive breast cancer diagnoses (n=1,681 and 4,555 cases, respectively). Multivariable adjusted hazard ratios [HR] and 95% confidence intervals [95% CI] were estimated using Cox proportional hazards regression. For Aim III, multivariable linear regression assessed cross-sectional associations between nSES and inflammatory serum biomarkers (adiponectin, leptin and C-reactive protein) among adults residing in California (n=6,919) and Hawaii (n=6,899) (2000-2017). Results: Cholesterol-lowering drug use (Aim 1) and duration was not associated with breast cancer risk among all women with no statistically significant heterogeneity in associations by race and ethnicity (p-interaction >0.05). In Aim 2 analyses, women with a higher HLI score (Tertile (T)) had a reduced risk of breast cancer (HRT3 vs T1: 0.76; 95% CI: 0.69, 0.84; HRT2 vs T1: 0.88; 95% CI: 0.79, 0.97) compared to women in the lowest HLI tertile with a significant dose-response observed (p-trend <0.01). Similar patterns were observed across all racial and ethnic groups of women. In California and Hawaii, individuals living in low nSES neighborhoods had higher serum levels of CRP (p-trend <0.001; p-trend = 0.02, respectively) and leptin (p-trend <0.001) while adiponectin levels were lower (p-trend <0.01; p-trend = 0.03, respectively) compared to individuals living in neighborhoods with high nSES. Additional adjustment for body mass index attenuated these associations (p-trend >0.05) (Aim III). Public Health Impact: Findings from this dissertation further support engaging in healthy lifestyle behaviors as a preventative strategy for breast cancer reduction among multiethnic populations of postmenopausal women whereas cholesterol-lowering drug use was not associated with reductions in risk. In addition, residing in low nSES neighborhoods was associated with less favorable inflammatory biomarkers levels.Item Examining Consumer Product Use And Phthalate Exposure Among Vulnerable Populations(2023) Boyle, Meleah; Quirós-Alcalá, Lesliam; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)One in 13 Americans have asthma, and higher rates have been reported among women and Black children.1 In addition, hairdressers who are exposed to chemicals through products used on themselves and their clients frequently report respiratory symptoms and conditions.2–10 Limited studies indicate that chemicals in personal care and consumer products (PCP) may impact respiratory health.11–14 The goal of this dissertation is to describe PCP use and exposures to recognized and suspected respiratory irritants (phthalates) among vulnerable populations who may experience disparate exposures. The aims are to: 1) characterize PCP use among 110 children with asthma, 2) examine associations between PCP use and asthma morbidity among 110 children with asthma, and 3) characterize concentrations and exposure determinants to phthalate metabolites in post-shift urine samples among 23 female hairdressers and 17 female office workers. In aim 1, participants were majority Black (87%), males (56%), and aged 8-11 years (66%). Adolescents (12-17 years) and females reported more frequent use of hair, face, and body products compared to children (8-11 years) and males. Participants used chemical treatments on their hair as young as 4 years and females 11-16 years used feminine wipes, spray, and regular deodorant in the genital area. For aim 2, use of aerosol products, hair products, and nail polish were positively associated with maximal symptom days [number of aerosol products (aOR: 1.36; CI: 1.17, 1.59), hairspray (aOR: 1.63; CI: 1.14, 2.33), perfume (aOR: 1.40; CI: 1.11,1.77); shampoo (aOR: 1.34; CI: 1.05,1.73), hair sheen (aOR: 1.41; CI: 1.00, 2.00), nail polish (aOR: 2.42; CI: 1.72, 3.41)] among children with asthma. For Aim 3, the geometric mean (GM) for monoethyl phthalate (MEP) was 10 times higher among hairdressers (161.4 ng/mL) than office workers (15.3 ng/mL). Hairdressers who provided chemical services had higher GM MEP concentrations than those who did not: texturizing (200.2 vs. 115.4 ng/mL), relaxing (181.6 vs. 92.1 ng/mL), bleaching (182.3 vs. 71.6 ng/mL), hair color (171.9 vs. 83.2 ng/mL), and Brazilian blowout (181.4 vs. 134.6 ng/mL). Hairdressers who provided natural services had lower GM MEP concentrations than those who did not: twists (129.1 vs. 215.8 ng/mL), sister locs/locs (86.0 vs. 241.9 ng/mL), and afros (94.7 vs. 203.9 ng/mL). While larger studies are needed, this dissertation provides new data on PCP use and phthalate exposure among Black children and hairdressers.Item SIMILAR VASCULAR RESPONSES TO A HIGH-FAT MEAL, REGARDLESS OF RACE AND SOCIAL DETERMINANTS OF HEALTH(2022) Weiner, Cynthia Marie; Ranadive, Sushant M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Black individuals are at a higher risk for developing cardiovascular disease (CVD), including hypertension, compared to white individuals. Chronic low-grade inflammation contributes to hypertension by causing vascular dysfunction, including increased vascular resistance. Young, healthy, normotensive black individuals exhibit heightened inflammatory biomarkers at rest, a possible factor in the higher prevalence of hypertension seen within this population. Vascular function decreases transiently as a result of an acute inflammatory stimulus, such as with consumption of a high-fat meal (HFM). However, there is limited evidence regarding the racial differences in inflammatory and vascular responses to a HFM in young, healthy black and white individuals. Furthermore, there are limited data regarding the association between social determinants of health (SDH) factors and the physiological components of inflammation and vascular responses. Therefore, the goal of the present study was twofold: to evaluate the racial differences in inflammatory and vascular responses to a HFM and to evaluate the potential impact of SDH factors on these relationships. Five black individuals (5 males, 21.2 ± 1.5 yrs) and 14 white individuals (7 males/7 females, 25 ± 4.1 yrs) completed the study. White individuals were significantly older than black individuals, but were similar in fitness status (VO2peak; 43.4 ± 10.8 ml/kg/min vs. 40.5 ± 5.9 ml/kg/min) and BMI (22.6 ± 2.9 kg/m2 vs. 23.5 ± 3.3 kg/m2). Black and white individuals exhibited similar vascular function, arterial stiffness, wave reflection, and hemodynamic variables (BP, HR) at baseline and following the HFM. Black individuals had a significantly lower total SDH score compared to white individuals, indicating lower SDH across seven domains assessed in the SDH questionnaire. However, SDH was not associated with any of the vascular measurements at baseline or following the HFM. Inflammation was not detected at baseline and following the HFM, as measured by a multiplex immunoassay. Therefore young, healthy black and white individuals maintain vascular function following a HFM, regardless of SDH status.Item Mental health and mental health services during the COVID-19 pandemic(2021) Benjenk, Ivy; Chen, Jie; Health Services Administration; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The COVID-19 pandemic significantly impacted mental health and mental health services in the United States. During February 2021, 42% of Americans experienced symptoms of depression or anxiety. During the pandemic, the largest and most sustained growth in telemedicine occurred in mental health services. The goal of this dissertation is to explore strategies for maintaining mental health services and promoting mental health during the COVID-19 pandemic. In this work, I review the literature on what is currently known about the impact of the COVID-19 pandemic on mental health and mental health services. I provide conceptual frameworks that posit how vulnerable populations are at highest risk for losing access to healthcare during the pandemic and how population-level strategies are needed to promote mental health recovery. In my first research paper, I use qualitative data collected from semi-structured interviews with twenty adults with serious mental illness (SMI) during the pandemic. I found that most study participants did not experience increases in unmet mental health or social service needs. However, several participants who lacked identification documents, housing, and/or a personal device reported significant increases in unmet needs, including inability to access mental health care and public benefits. As many participants in the qualitative study reported receiving audio-only telemental health services versus video telemedicine during the pandemic, I used data from the Medicare Current Beneficiary Survey COVID-19 Supplements to explore the use of audio-only telemedicine during the pandemic. Findings suggest that the high rate of audio-only telemedicine is not exclusively related to the digital divide or patient preferences, but also to provider behavior. Lastly, as the COVID-19 pandemic impacted the mental health of the entire population, I used data from the Census Bureau’s Household Pulse Survey to explore whether availability and receipt of an effective COVID-19 vaccine could promote mental health. Results suggest a reduction in the predicted probability of mental health symptoms after approval of the vaccine and a lower predicted probability of mental health symptoms among those who have been vaccinated, however these rates remain higher than what was seen prior to the pandemic. Overall findings suggest that the mental health care system has adapted fairly well to meet the needs of persons with SMI during the pandemic and mental health has improved since the approval of the vaccine, but additional work will be needed to reengage those who were disconnected from mental health services during the pandemic and to achieve pre-pandemic levels of mental health.