Theses and Dissertations

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21775

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State Cannabis Laws, Risk Perceptions, and Delta-8 THC Use among Young Adults
(2022-12) LoParco, Cassidy R.; Rossheim, Matthew; Walters, Scott T.; Zhou, Zhengyang
Background: Delta-8 THC, a federally unregulated psychoactive substance, has been rising in popularity. Although no prevalence data exist, calls to U.S. poison control have been increasing. Preliminary research indicates Google search trends relating to Delta-8 THC are higher in states where adult non-medical use of Delta-9 THC is not legal. Theoretical models posit that perceived risk is a theoretical antecedent of risk behavior. However, no research has examined associations between state cannabis laws, perceived risk, and Delta-8 THC use. Methods: Amazon MTURK was utilized to recruit participants aged 18-25-years-old to answer an online survey (n = 603 responses). Rigorous quality control methods were undertaken to ensure the quality of the data, resulting in a final analytic sample size of n = 166. Multivariable logistic regression models were used to examine whether the following factors were associated with the odds of using Delta-8 THC in the past year: 1) state Delta-8 THC laws, 2) state Delta-9 THC laws, 3) Delta-8 THC perceived susceptibility, 4) Delta-8 THC perceived severity, 5) Delta-9 THC perceived susceptibility, 6) Delta-9 THC perceived severity, and 7) past year Delta-9 THC use, adjusting for age, race/ethnicity, birth sex, and student status. Results: Almost one-quarter (22%) used Delta-8 THC in the past year. Associations between state cannabis laws (both Delta-8 and Delta-9 THC) and Delta-8 THC use were not statistically significant. Participants with higher levels of Delta-8 THC perceived susceptibility and Delta-9 THC perceived severity, and lower levels of Delta-8 THC perceived severity and Delta-9 THC perceived susceptibility, had significantly higher odds of using Delta-8 THC in the past year. Those who engaged in Delta-9 THC use in the past year had 14 times the odds of also engaging in Delta-8 THC use. Conclusions: This was the first study to examine how cannabis risk perceptions are associated with Delta-8 THC use. Findings indicated that most Delta-8 THC users were also users of Delta-9 THC, suggesting possible polysubstance use or substitution. Strong, statistically significant associations were observed between cannabis risk perceptions and Delta-8 THC use, which has important implications for harm reduction interventions. Future longitudinal research, with large nationally representative samples, is needed to fully understand associations and potential causality.
The influence of race/ethnicity and social determinants of health and HPV vaccination in vaccine-eligible adults in the U.S.
(2022-08) Garg, Ashvita; Thompson, Erika; Nguyen, Uyen-Sa D.T.; Luningham, Justin M.
Background: Human Papillomavirus (HPV) vaccination is an essential primary prevention measure against HPV-related cancers, currently approved for catch-up for inadequately vaccinated adults by age 26 and for mid-adults aged 27-45 with shared clinical decision-making. Although HPV vaccination rates have been gradually increasing, racial/ethnic disparities and low catch-up among adults persist. Examining the Social Determinants of Health (SDOH) associated with HPV vaccination in different racial groups may help explain these disparities in lower vaccine uptake. Previous studies using national datasets have found differences in estimated prevalence of HPV vaccine uptake across datasets for racial/ethnic minorities, especially for Asian Americans, when compared to non-Hispanic White, with results varying from lower to higher uptakes. Despite Asian Americans being a very diverse racial group, most studies either combine them in one category or with other races, resulting in an incomplete picture of HPV vaccine uptake among different Asian American subgroups. Purpose: Using the SDOH framework, this study aimed to examine the racial/ethnic differences for HPV vaccination across three U.S. national databases among vaccine-eligible adults and examine the association between HPV vaccination and Asian racial subgroups. Methods: For the first aim, the study utilized 2017-2019 NHIS (n=30,788), 2017-2020 pre-pandemic NHANES (n=3,685), and 2017-2019 BRFSS (n=30,324) data, ages 18-45 years. Asian racial subgroup disparities for the second aim were assessed with 2014-2018 NHIS data (n=34,839, ages 18-38). Survey-weighted multivariable logistic regression models identified the association between HPV vaccination status (outcome) and explanatory variables: SDOH indicators, race/ethnicity, sex, nativity, and age. Results: The racial/ethnic differences in HPV vaccine uptake were not similar between the three datasets. In the NHIS dataset, compared to Non-Hispanic White, Non-Hispanic Asian and Non-Hispanic Asian males were more likely to be vaccinated. With NHANES data, Non-Hispanic Asian males were less likely to be vaccinated. While BRFSS data did not show statistically significant differences in HPV vaccination for difference races/ethnicity. However, inverse variance weighted averages indicated that compared to Non-Hispanic White, Non-Hispanic Asian individuals had higher odds of receiving HPV vaccination. Males compared to females and foreign-born compared to U.S.-born individuals were less likely to be vaccinated. Among SDOH factors, education level, time since last healthcare visit, health insurance status, and having a usual place of healthcare were significantly associated with HPV vaccination. Compared to White individuals, Asian Indian were less likely to be vaccinated while Filipino and individuals from other Asian subgroups were more likely to be vaccinated. Additionally, foreign-born Asian Indian compared to foreign-born White individuals and Asian Indian females compared to White females were less likely to be vaccinated. Regarding SDOH factors, education level, insurance status, and time since last healthcare were significantly associated with HPV vaccination. Conclusion: This study identified racial/ethnic differences in HPV vaccine uptake and SDOH indicators associated with HPV vaccination. Findings indicate that more studies are needed to assess the differences in these three surveillance systems that led to the conflicting findings and to explore the reasons for lower vaccination uptake among the Asian Indian population. Finally, tailoring HPV vaccine awareness campaigns and improving vaccination access for males, foreign-born, individuals lacking health insurance, or those failing to have regular healthcare visits could help promote HPV vaccination and reduce HPV-associated cancers.
Lessons Learned from the Design and Implementation of a Health Promotion Intervention for African American Women
(2022-08) Dodgen, Leilani, A.; Spence-Almaguer, Emily
The purpose of this dissertation is to explore how intervention design can be enhanced to influence the health of African American women through examining the processes and methods related to health behavior theory, cultural adaptation, and participatory approaches. Data from African American women who participated in the Better Me Within (BMW)Trial, as well as, formative data from focus groups with African American women were used to investigate these intervention planning approaches through the following aims: Aim 1 addressed the question how do theoretical constructs of behavior change help to explain health outcomes in the BMW trial? This was quantitatively explored by examining theoretical constructs with outcomes of weight, diet and physical activity. Aim 2 explored the perspectives of African American women through qualitative analysis of focus groups for cultural and contextual elements that may influence the approach to intervention design, increase knowledge about cultural adaptations, and contribute methods to enhance weight management. Aim 3 critically examined how the community-based participatory research (CBPR) approach with African American faith communities in the BMW Trial aligned with the CBPR conceptual model through a case study. Understanding how processes, operations, and decisions in intervention design contribute to health improvements is imperative for ensuring programs are relevant and effective in specific populations. One size does not fit all. The current state of health inequities and chronic conditions in African American women require thoughtful intervention strategies that center community knowledge, culture, and context. This dissertation seeks to arrive at intervention strategies that are relevant to African American women, and influence how public health professionals approach intervention development for meaningful, community-identified health improvements.
ASSESSING REPRODUCTIVE INTERCONCEPTION CARE BEHAVIORS, BARRIERS, AND FACILITATORS AMONG WOMEN RECENTLY PREGNANT AND HOMELESS
(2022-08) Galvin, Annalynn M.; Thompson, Erika; Lewis, Melissa; Walters, Scott T.
Interconception care, care provided to mothers between pregnancies, reduces short birth interval risks such as prematurity and low birthweight. Women experiencing homelessness have higher rates of unintended pregnancy and may experience stronger benefits from reproductive interconception care through either unintended pregnancy reductions or healthy pregnancy promotion via family planning. It is critical to build on limited research on interconception care within this population to potentially reduce poverty and cyclical, intergenerational homelessness. By utilizing a sequential explanatory mixed-methods design, this proposed study aimed to first determine prevalence ratios of interconception behaviors such as attendance of maternal postpartum visits, birth spacing and family planning counseling, and postpartum contraception outcomes of women experiencing homelessness, then identify the most salient interconception barriers and facilitators related to interconception information (e.g., knowledge), motivation (e.g., personal attitudes), and behavioral skills (e.g., perceived self-efficacy) among postpartum women who experienced homelessness during pregnancy. Using the 2016-2019 Pregnancy Risk Assessment and Monitoring System, the prevalence of interconception care behaviors among women experiencing homelessness and the associations between housing status and interconception care behaviors were estimated. The sample (n=100,706) was primarily non-Hispanic White (59.4%), married (61.9%) women with private insurance (59.4%) and less than a 4-year degree (63.0%). Approximately 2.4% of participants experienced housing instability in the 12 months before their child was born. Perinatal housing instability was significantly associated with lower odds of attending a postpartum maternal visit (aOR=0.45, 95% CI 0.37, 0.56) and (aOR=1.30, 95% CI 1.07, 1.57) when compared to women who did not experience homelessness in the last 12 months from the time of the interview. Findings from aim 1 determined specific interconception care behavior deficits to further explore via one-hour semi-structured interviews with 12 women experiencing homelessness while pregnant who had given birth within the last four years. Eligible women were recruited through local agency partnerships using purposive sampling. Interviews were audio-recorded, coded to consensus, and analyzed for themes. Information-related themes included knowledge and misconceptions about perinatal processes (e.g., pregnancy, labor and delivery, becoming pregnant, preventing pregnancy) as well as information-seeking themes. Motivation-related themes included attitudes about recent interconception care experiences, perinatal social influences, perceived susceptibility to future pregnancy, and attitudes regarding reasons for not engaging in postpartum pregnancy prevention. Behavioral skill-related themes included objective ability to engage in perinatal behaviors during housing instability, as well as perceived self-efficacy related to barriers and facilitators to engaging in reproductive interconception pregnancies as well as ease of pregnancy. Macro-related themes included housing effects on perinatal period, how perinatal experiences affected seeking stable housing, and how the interconnected nature of housing and other macro-level factors influenced reproductive interconception care. These findings establish a baseline understanding of interconception behaviors and the associated barriers and facilitators related to interconception care information, motivation, and behavioral skills among women experiencing homelessness. Findings may potentially strengthen current interconception practices and augment reductions in unintended pregnancy, short birth intervals, or adverse birth outcomes in future pregnancies, thus improving pregnancy outcomes and improving the health of women before, during, and after pregnancy.
The influence of spatial patterns and dengue serotype on dengue fever severity in Mexico
(2022-08) Annan, Esther; Haque, Ubydul; Nguyen, Uyen-Sa D.T.; Nandy, Rajesh R.
Low socioeconomic status (SES), high temperature, and increasing rainfall patterns are associated with an increase in the number of dengue case counts. However, the effect of climatic variables on individual dengue virus (DENV) serotypes have not been explored in prior literature. Furthermore, there is a knowledge gap about the extent to which serotype count affects the rate of severe dengue in Mexico. A principal components analysis was used to determine the poverty indices across Mexico. Conditional autoregressive Bayesian models were used to determine the effect of poverty and climatic variables on the rate of serotype distribution and severe dengue in Mexico. A unit increase in poverty increased the rate of DENV-1, DENV-2, DENV-3, and DENV-4 by 8.4%, 5%, 16%, and 13.8% respectively. An increase in one case attributable to DENV-1, DENV-2, DENV-3, and DENV-4 was independently associated with an increase in the rate of severe dengue by 0.02%, 0.1%, 0.03%, and 5.8% respectively. Hotspots of all DENV serotypes and severe dengue were associated mostly with coastal regions in Mexico. The Southeast region experienced higher humidity, a higher poverty index, and a lower average altitude. The association of these climatic parameters with severe dengue puts states like Oaxaca at increased risk of a higher number of severe dengue cases. Pregnancy increases a woman's risk of severe dengue. To the best of our knowledge, the moderation effect of dengue serotype among pregnant women has not been studied in Mexico. This study explores how pregnancy interacts with dengue serotype from 2012 to 2020 in Mexico. Information from 2,469 notifying health units in Mexican municipalities was used for the analysis. Multiple logistic regression with interaction effects was chosen as the final model and sensitivity analysis was done to assess potential exposure misclassification of pregnancy status. Pregnant women were found to have higher odds of severe dengue [1.50 (95% CI: 1.41, 1.59)]. The odds of dengue severity varied for pregnant women with DENV-1 [1.45, (95% CI: 1.21, 1.74)], DENV-2 [1.33, (95% CI:1.18, 1.53)] and DENV-4 [3.78, (95% CI: 1.14, 12.59)]. While the odds of severe dengue were generally higher for pregnant women compared with non-pregnant women with DENV-1 and DENV-2, the odds of disease severity were much higher for those infected with the DENV-4 serotype. Future studies on genetic diversification and phylogeny may potentially elucidate this serotype-specific effect among pregnant women in Mexico.
Structural Determinants of Health Among Transgender Populations: Policing, Sex Work, and HIV
(2023-12) Webb, Nathaniel J.; Kline, Nolan; Griner, Stacey; Rossheim, Matthew; Yockey, Andrew
Transgender (trans) populations experience disproportionately high rates of HIV infection compared to cisgender populations. Additionally, due to overlapping layers of discrimination in education, housing, healthcare, and employment, trans populations are more likely to engage in a criminalized form of work, such as sex work. Policing has been identified as a potential structural determinant of HIV infection among individuals engaging in sex work. Trans populations, including those engaging in sex work, are more likely to interact with police and experience some form of police violence. This dissertation investigated policing as a potential structural determinant of HIV status and HIV testing among trans individuals who engage in sex work. Unadjusted and adjusted logistic regression analyses were utilized to identify associations between HIV status/HIV testing and police interactions. Mediation analyses were utilized to investigate police interactions as a potential mediating variable between HIV status/HIV testing and trans individuals who have engaged in street-based sex work. Statistically significant associations were identified between police interactions and HIV status in unadjusted (OR: 2.564, 95% CI: 1.166, 5.641, p-value = 0.019) and adjusted (aOR: 12.055, 95% CI: 3.076, 47.232, p-value <0.001) logistic regression models. Additionally, police interactions were not identified as a statistically significant mediating variable between HIV status/HIV testing and trans individuals engaging in street-based sex work. These findings suggest policing may act as a contributing factor towards HIV infection among trans individuals engaged in sex work, but further research is needed to elucidate this interaction. HIV infection prevention interventions need to include an intersectional lens that incorporates trans identities and address the structural issues that trans populations experience including discrimination in housing, employment, and healthcare.
The Effects of Cognitive Impairment on Hospitalizations in Heart Failure Patients
(2018-05) Bhatti, Megan
Background: Heart failure (HF) is a major health problem in the United States (US) linked to poor survival rates, high rehospitalization rates and high healthcare cost. HF is positively associated with aging and its impact on US health and healthcare systems is expected to grow as the baby boomer generation enters their retirement years. The same is true for another chronic health risk, cognitive impairment. There is a clear, negative impact on prognosis and healthcare outcomes associated with cognitive impairment in HF patients, but less is known about how these affect systems outcomes such as overall hospitalization. The aim of this study is to compare hospitalization patterns among HF patients with and without comorbid cognitive impairment to identify associated risks and outcomes. Methods: We performed a cross-sectional study of adults over the age of 45 with a diagnosis of heart failure. The data for this analysis was obtained from the 2014 Medical Expenditure Panel Survey (MEPS). Statistical analyses were performed using SPSS. Differences in the distribution of risk for patients with and without cognitive disorders were evaluated using weighted Chi-squared tests. A weighted logistic regression was used to find factors associated with hospitalization risk by examining associations among demographic and other characteristics with the outcome. Results: A total of 175 adults were studied. There was evidence of a statistically significant association between the presence of cognitive impairment and hospitalization (X² = 5661.545, p<0.0001). However, the association between the two was very weak (Cramer's V = 0.053, p<0.000; Pearson's R = -0.053, p<0.000). A logistic regression model was fit to assess associations between the outcome and insurance coverage, cognitive impairment, race, sex, age, annual family income and education. The odds of hospitalization were 1.15 times more when a subject is uninsured, as compared to those who were insured (p<0.0001), all other factors held constant. Similarly, those without cognitive impairment had 1.33 times the odds of hospitalization compared to that of those with cognitive impairment (p<0.0001). White subjects were found to have an 88% increase in odds of hospitalization compared to their non-White counterparts (p<0.0001). Men were expected to have a 13% increase in odds of hospitalization (p<0.0001). Younger age was a protective factor; there was a 40% reduction in odds of hospitalization for subjects under 65 years old (p<0.0001). Subjects with an annual family income under $35,000 were at 2.5-fold increased odds of hospitalization (p<0.0001). Education also showed to be a significant protective factor. Subjects with less than a high school education had 5.3 times the odds of hospitalization compared to subjects with at least a Bachelor's degree. Subjects with a high school diploma and/ or some college had a 2.4-fold increase in odds of hospitalization compared to those with at least a Bachelor's degree (p<0.0001). Conclusions: Consistent with the literature, populations with older age, less education and lower income were at a higher risk of hospitalization. However, this study ultimately found no evidence that supports the theory that cognitive impairment affects hospitalizations in heart failure patients. It is plausible that the high prevalence and relatedness of comorbidities between cognitive impairment, race, socioeconomic status, education, and age simply mask the effects of cognitive impairment on hospitalizations. These results warrant the continued study of the effects of cognitive impairment and number of hospitalizations, in addition to overall risk of hospitalization.
The Association Between Sleep Traits and the Risk of Lung Cancer: UK Biobank Cohort
(2022-05) Peeri, Noah C.; Nguyen, Uyen-Sa D.T.; Tao, Meng-Hua; Demissie, Serkalem
Background: Lung cancer has the highest incidence of any cancer and is the leading cause of cancer-related death worldwide. As smoking rates have declined over the last few decades, the proportion of individuals diagnosed with lung cancer among those who have never smoked increases. Thus, it remains important to identify other factors involved in the etiology of the disease. Sleep traits have been hypothesized as potential modifiable risk factors for lung cancer. This dissertation aimed to 1) comprehensively examine the associations between sleep traits and lung cancer risk using traditional epidemiologic methods (e.g., Cox regression) and 2) to assess potential causal associations between sleep duration (per hour increase) and lung cancer risk, insomnia (per category increase) and lung cancer risk, and chronotype (per category increase) and lung cancer risk using Mendelian randomization (MR) analyses. Methods: Utilizing the United Kingdom Biobank Cohort I examined the association between sleep traits (sleep duration, chronotype, insomnia) and lung cancer risk. Cox Hazards regression was used to estimate Hazards Ratios (HRs) and 95% Confidence Intervals (CIs) of associations between these three sleep traits and lung cancer risk. Joint effects analyses were also conducted, and non-linearity of sleep duration and lung cancer risk associations was examined. MR analyses were conducted to estimate causal HRs for the associations between sleep duration, chronotype, insomnia, and lung cancer risk. Analyses were stratified by smoking status to examine associations unconfounded by smoking (i.e., among never smokers). Furthermore, analyses were stratified by biologic sex and smoking to examine potential effect measure modification of associations between sleep traits and lung cancer risk. Results: Results of this study suggested potential associations between sleep traits and lung cancer risk. In main effects analysis, long sleep, when compared to short sleep duration was positively associated with lung cancer risk. Usually experiencing insomnia symptoms, when compared to never/rarely experiencing insomnia symptoms, was positively associated with lung cancer risk. No associations between chronotype and sleep duration were evident in overall analysis. Evidence from both aims suggested positive associations between the presence of insomnia symptoms and lung cancer risk. However, among never smokers, no statistically significant associations were observed in either aim. Two-sample MR revealed minute positive associations between insomnia and lung cancer risk. Discussion: In this dissertation the association between insomnia and lung cancer risk may have been residually confounded by smoking status; among never smokers no evidence was found linking insomnia and lung cancer risk. In one-sample MR analysis, the strong positive association between insomnia and lung cancer risk may have resulted from violations of the independence assumption. In stratified one-sample MR, no association between insomnia and lung cancer was observed among the neversmoker strata. It remains unclear to what extent the observed association between insomnia and lung cancer risk in two-sample MR was impacted by smoking status. Future research should focus on examining associations between insomnia and lung cancer among a larger cohort of never smoking individuals. In conclusion, the associations observed between insomnia and lung cancer were likely impacted by smoking status, and future research is needed to tease apart the impact of smoking on lung cancer from that of insomnia on lung cancer.
The role of built environment and private rooms for reducing hospital acquired infections
(2019-08) Park, Sae Hwan; O'Neill, Liam
Increased use of private patient rooms may be an important adjunct to traditional process-based interventions to prevent hospital-acquired infections (HAIs) in inpatient settings. We examined whether private room assignment lowers the risk of developing hospital-acquired methicillin-resistant staphylococcus aureus (HA-MRSA) infection and whether percent private rooms at the hospital level explain hospital-to-hospital variation in HA-MRSA incidence. We used 2016 Texas Department of State Health Services inpatient data from 340 acute care hospitals to evaluate HA-MRSA incidence. We used matched cohorts generated from 2.7 million Texas inpatients to estimate attributable incidence and outcomes of HA-MRSA or other (methicillin-sensitive) staphylococcus infection. We also simulated potential financial impacts of an all-private room design for two dissimilar hospitals using the Monte Carlo method. MRSA and relevant conditions were assessed via ICD-10-CM diagnosis codes. We found a significant negative relationship between increased private room presence and use and HA-MRSA risk. The value of these protections can be quantified—we estimated each HA-MRSA infection prevented could have saved $12,100 in cost and reduced mortality risk by 4%. Additional simulation estimated substantial cost-savings, up to about $3 million, for a large public safety-net hospital if it were renovated to an all-private room design, with an 11% return on investment on average. Overall, our findings support renovation of existing bay-room oriented facilities to an all-private room design as an effective and potentially efficient means to increase inpatient safety. Our methods provide a useful means for policy makers, hospital boards, and others to evaluate the costs and benefits of such changes. Finally, we conclude that private room related metrics could provide an important quality indicator if included in public reporting.
Do brief motivational interventions increase motivation for change in drinking among college students? A meta-analysis of individual participant data
(2022-08) Tan, Zhengqi; Mun, Eun-Young; Walters, Scott T.; Zhou, Zhengyang; Huh, David; Nandy, Rajesh R.
Brief Motivational Interventions (BMIs) have been identified as one of the most effective individually focused alcohol intervention strategies for college students in the United States. Despite the central role of motivation for change in BMIs, whether BMIs increase motivation for change has rarely been investigated. The current study conducted a meta-analysis of individual participant data (IPD; 15 studies, N = 5,903) from Project INTEGRATE (Mun et al., 2015) to examine whether BMIs increase motivation for change in drinking. Different measures and responses used in the original trials were harmonized across studies, and effect size estimates were derived from a model that adjusted for baseline motivation and demographic variables for each study (step 1) and subsequently combined in a random-effects meta-analysis model (step 2). After adjustment for baseline levels of motivation level and demographic variables, the intervention effects of BMIs on motivation for change was not statistically significant (standard mean difference [SMD]: 0.026, 95% CI: [-0.001, 0.053], p = .06, k = 19). Subsequent metaregression analyses among BMI subtypes indicated that the intervention effect did not differ between individually delivered motivational interviewing with personalized feedback (MI+PF), stand-alone personalized feedback (PF), and group-based motivational interviewing (GMI). Among all BMI subtypes, only GMI had a statistically significant intervention effect on motivation compared to controls (SMD: 0.055, 95% CI: [0.007, 0.103], p = .025, k = 5). Within the first three months post-intervention, there was a decrease in SMD of 0.05 (95% CI: [0.01, 0.08]) in motivation per month. However, no statistically significant difference in the intervention effects was found between studies with short-term vs. long-term follow-up. Although the results from the current study do not support the hypothesis that BMIs improve motivation for change, the evidence as a whole suggests ways in which motivation may be improved following intervention and can be tested in future studies.
Improving the Efficiency of A and D Optimal Designs for Dose Response Models
(2021-08) Jasti, Srichand; Nandy, Rajesh R.; Aryal, Subhash; Thombs, Dennis; Barnett, Tracey; Haque, Ubydul
For A-optimality, by virtue of Cramér–Rao bound, the trace of the inverse of Information matrix for the parameters serves as a lower bound for the sum of variances of the estimators and the bound is attained asymptotically. Hence, asymptotically, A-optimality is achieved by minimizing the trace of the inverse of the Information matrix. For non-linear models, Cramér–Rao bound is crude for finite samples and hence the asymptotic solution can be very different from the design that minimizes the sum of variances. We explore the validity of the asymptotic solution by directly minimizing the sum of variances using numerical methods in a restricted search space. We demonstrate that even in a very restrictive search space of point symmetric designs, the theoretical solution is half as efficient for a sample size of 100. Further improvement can be achieved by relaxing the restriction of the solution being point symmetric. The solution to A and D optimal designs for the logistic model depend on the unknown parameters of the model. Therefore, to obtain an optimal design the experimenter must inform the design based on some prior knowledge, or a guess, of the unknown parameters. This is a severe limitation on the ability to identify an optimal design especially when there is little prior information to inform the guess. Here we explore the use of a two-stage A-optimal design for finite samples and three-stage D-optimal design for large samples to mitigate the loss in efficiency which may arise due to poor guess values. We demonstrate that while two-stage finite sample model results in gain in efficiency with small sample sizes at 70% allocation to the first stage. The three-stage D optimal design is shown to be almost always better than the single stage and the corresponding two-stage design.
Sickle Cell Disease Awareness, Willingness to be Tested and Willingness to Participate in Genetic Counseling Among African Immigrants of the Democratic Republic of Congo in North Texas
(2020-05) Njesada, Ndolembai S.; Nandy, Karabi; Sterling, David; Raines-Milenkov, Amy; Young, Richard
The aim of this exploratory cross-sectional research was to assess the awareness of Sickle Cell Disease (SCD), the willingness to be screened for SCD, and the willingness to participate in genetic counseling among African immigrants from the Democratic Republic of Congo who resided in North Texas through in-person surveys. A structure questionnaire containing 36 SCD questions was administered to DRC immigrants residing in Dallas-Fort-Worth-Denton-Arlington metroplex of North Texas between August and November 2019. One hundred and eighty-six were successfully interviewed. SCD awareness was very high among participants (97%); however, only about 65% agreed to participate in SCD testing and 72% to genetic counseling. Statistical significance in the levels of awareness, willingness to be screened and to participate in genetic counseling was noted between males and females. Education was negatively associated with awareness of SCD. Those who had less than high school education had higher odds of being aware of sickle cell compared to those who had more than high school education. However, those who had refugee immigration status had seven times higher odds of being willing to participate in SCD testing compared to permanent resident status. There is a need for SCD education among immigrants from endemic countries like DRC, given that almost half of the participants were not willing to participate in SCD educational programs. The need of mix methods studies to understand the various patterns of association related to all the factors associated with sickle cell disease is warranted.
Environment-Wide Association Study on Childhood Obesity
(2020-05) Uche, Uloma I.; Suzuki, Sumihiro; Zhou, Zhengyang; Fulda, Kimberly
Background: Obesity is both a global and national public health issue with increasing prevalence over the last decades. It is associated with adverse health effects as well as social and economic costs. Both children and adults are affected; however, much more impact and prevalence are seen in children because of their growing bodies. While the etiology and prevention of childhood obesity are not fully understood, studies have linked it to lack of built environment, diet, lack of physical activities, and genetic susceptibility, with growing evidence that it could also result from other environmental factors. Studies linking it to other environmental factors are quite limited, unsystematic, incomprehensive and inconclusive. Thus, using the concept of an environment-wide association study (EWAS) and while accounting for already known risk factors (lifestyle factors) associated with childhood obesity, the aims of this dissertation were 1) to comprehensively and systematically investigate all the environmental factors available in the National Health and Nutrition Examination Survey (NHANES) to determine factors associated with childhood obesity and 2) to validate my findings from aim1 on a different cohort of children and adults to see if factors persist. Methods: I utilized NHANES datasets 1999-2016, retrieving data files for children/adolescents (6-17yrs) and adults (>18yrs). Obesity was measured using BMI measures and waist to height ratio. A multinomial and binary logistic regression was conducted while adjusting for age, sex, race/ethnicity, creatinine, calorie intake, physical activity, screen time (TV hours & computer/video games hours), limitation to physical activities, and socioeconomic status. As in EWAS, multiple hypothesis testing was controlled, and validation analyses were done. Results: I found that metals such as beryllium (OR: 3.305 CI: 1.460-7.479) and platinum (OR: 1.346 CI: 1.107-1.636); vitamins such as gamma- tocopherol (OR: 8.297 CI: 5.683-12.114) and delta- tocopherol (OR: 1.841 CI:1.476-2.297); heterocyclic aromatic amines such as 2-Amino-9H-pyrido (2,3-b) indole (A-a-C) [OR: 1.323 CI: 1.083-1.617] and 2-Amino-3-methyl-9H-pyriodo[2,3-b]indole (MeA-a-C) [OR: 2.799 CI: 1.442-5.433]; polycyclic aromatic amines such as 9- fluorene (OR: 1.509 CI: 1.230-1.851), 4- phenanthrene (OR: 2.828 CI: 1.632-4.899) and caffeine metabolites such as 1,3,7-trimethyluric acid (OR: 1.22 CI: 1.029-1.414) and 1,3,7-trimethylxanthine(caffeine) (OR: 1.258 CI: 1.075-1.473) were positively and significantly associated with childhood obesity. More so, I found that factors such as gamma- and delta-tocopherols, as well as manganese, copper, caffeine, 2-napthol and 2-phenanthrene were associated with both childhood and adulthood obesity. Finally, I found that vitamin B6, B12 and C as well as carotenoids, enterolactone, harmane and iron are protective factors of both childhood and adulthood obesity. Discussion: These novel findings are of public health significance since these factors are potentially modifiable risk factors of childhood obesity and they are valuable for prevention and reducing the risk of obesity among U.S. children and adolescents. Exposures to some of these factors are mainly from vehicle exhaust, tobacco combustion, tea, and contaminated air and water. They may have the capability of eliciting stress, inhibiting enzymes needed for metabolic processes or disrupting lipid homeostasis which subsequently increases the risk of obesity. Conclusion: Despite the difficulty of ascertaining causality, this dissertation found novel pathways to the etiology of childhood obesity as well as adulthood obesity that needs further investigation.
Using big data for improving two surveillance systems: influenza surveillance using Google flu-related search query data and probationers absconding surveillance using chronological case notes data
(2020-05) Liu, Jialiang; Suzuki, Sumihiro; Mun, Eun-Young; Nandy, Rajesh R.
Abstract Title: Using big data for improving two surveillance systems: influenza surveillance using Google flu-related search query data and probationers absconding surveillance using chronological case notes data. Objectives: The overall goal of this dissertation is to explore the feasibility of using big data to create innovative strategies to improve two surveillance systems, influenza surveillance, and probationers absconding surveillance. Flu surveillance - Under the current gold standard for flu surveillance in the US conducted by the CDC, there is always a delay of up to three weeks between the occurrence of flu season onset and dissemination of this information. To this end, the first goal of this dissertation was to test an innovative strategy that applies a statistical detection algorithm to the near real-time seasonal flu activity data to predict the onset of flu season weeks prior to the flu season beginning. Probationers absconding surveillance - In the US legal system, probation is the most widely used alternative sanction to incarceration. However, there is a significant segment of probationers who fail to complete probation by absconding from supervision. Due to the limited financial resources and the increasing population of probationers, little effort has been made toward locating and examining these probation absconders. Our second goal was to explore words and phrases associated with probation absconders by applying natural language processing (NLP) techniques to official chronologic case notes written by probation officers. Methods: Flu surveillance - we applied the modified Bayesian online change point detection (BOCPD) algorithm to real-time flu activity data obtained from the AutoRegression with General Online (ARGO) data model. The ARGO model uses Google flu-related search query data and historical CDC flu activity data to estimate flu activity in a real-time fashion. We used change point detection methods on the ARGO data to predict the dates of flu season onset and compared them to those reported by the CDC from 2007 to 2015. In applying the BOCPD algorithm to the ARGO data, we developed systematic ways to satisfy the necessary assumptions of the BOCPD algorithm making it more robust and practical for flu surveillance, and we proposed a method to determine informative change points that may signal the onset of flu seasons. Probationer absconding surveillance - We applied a text regression method known as concise comparative summarization (CCS) method to text data generated from case notes of a random sample of adult misdemeanors and felony offenders who have received probation in Tarrant County, TX. Results and conclusions: Flu surveillance - Our strategy of flu surveillance exhibits a high accuracy of prediction with the proportion of correct prediction being 86%. Additionally, our strategy on average detected flu season onset three weeks prior to the official flu season onset. Probationer absconding surveillance - We found phrases such as "cannabinoids", "technical violations", "failed pay", and "transfer intake" to be associated with probation absconding. This suggests that probationers who had a history of using cannabinoids, violating probation conditions, failing to pay supervision fees during their probation periods, and those who were transfer cases tended more likely to be absconders. Meanwhile, phrases such as "everything going well", "travel", and "fees paid full" were found to be associated with probation completers. This implies that successful completers tended to have positive attitudes and willingness to share their personal life and feelings as well as having a stable income source to pay supervision fees. Currently, the case notes are kept only for record-keeping purposes. Our study identified previously unknown commonalities in the case notes of absconders and completers and may contribute to a new surveillance system that uses case notes systematically.
Lifestyle Factors and Depressive Symptoms Among Permanent Supportive Housing Residents
(2020-05) Holmes, Esther J.; Walters, Scott T.
Background: Depression is prevalent among low-income populations. Many lifestyle factors may influence depressive symptoms, including vegetable and fruit intake, physical activity, tobacco use, alcohol use, social support, and satisfaction with leisure activities. However, the influence of lifestyle factors on depressive symptoms among permanent supportive housing (PSH) residents is unclear. In addition, it is unclear if PSH residents with depressive symptoms are interested in working on lifestyle factors. Methods: A longitudinal analysis was conducted among 420 PSH residents participating in a technology-assisted health coaching program. Three timepoints were included, corresponding with the screening/baseline, six-month, and twelve-month assessment visits. The independent variables were total vegetable and fruit intake, physical activity, tobacco use, alcohol use, social support, and satisfaction with leisure activities. The dependent variable was depressive symptoms, measured by the 9-item Patient Health Questionnaire (PHQ-9). Covariates were race, sex, age, and visit. In addition, social support was examined as a potential effect modifier. Participants' interest in working on health areas was evaluated as well. Results: Moderate alcohol consumption predicted lower depressive symptoms compared with heavy alcohol consumption (b=-1.54, p=0.01). Additionally, the difference in depressive symptoms between non-consumers and heavy consumers of alcohol approached statistical significance with non-consumers of alcohol having less depressive symptoms than heavy consumers of alcohol (b = -.76, p = .07). High compared with low satisfaction with leisure activities (b=-0.83, p<0.0001) and high compared with low social support (b=-1.86, p<.0001) predicted lower depressive symptoms. Tobacco use was a marginally statistically significant predictor of depressive symptoms (b=0.92, p=0.05). Total vegetable and fruit intake and physical activity were not statistically significant predictors of depressive symptoms. Social support was not a statistically significant modifier of the effect of lifestyle factors on depressive symptoms. Participants with moderate, moderately severe, and severe depressive symptoms were most interested in working on diet, exercise, and substance use and least interested in working on social support and recreation/leisure activities. Conclusions: Alcohol use, tobacco use, social support, and satisfaction with leisure activities may influence depressive symptoms among PSH residents. However, participants may not be interested in working on social support and satisfaction with leisure activities. An ecological approach may be necessary to influence social support and satisfaction with leisure activities among PSH residents. Lifestyle interventions designed to reduce depressive symptoms among PSH residents should aim to increase PSH residents' social support and satisfaction with leisure activities.
The impact of medication therapy management on polypharmacy in people living with HIV/AIDS
(2020-08) Orimoloye, Helen Tolulope; Suzuki, Sumihiro; Clay, Patrick G.; Rasu, Rafia S.
Polypharmacy, defined as the concurrent use of multiple medications simultaneously, is increasingly common in people living with HIV/AIDS (PLWHA) due to the use of antiretroviral and non-antiretroviral drugs for the treatment of multiple chronic diseases. Polypharmacy is a growing concern among PLWHA because of their complex medication regimen, the risk of adverse drug events, drug-drug interactions, medication non-adherence, medication errors, and antiretroviral treatment failure. Medication therapy management (MTM), which are pharmacist-led interventions, have been useful in resolving medication-related problems and optimizing clinical outcomes. However, there are limited studies on the effectiveness of pharmacist-provided MTM services in reducing polypharmacy in HIV/AIDs patients. MTM services should enable the identification and reduction of polypharmacy. Hence, the central goal of this dissertation was to evaluate the impact of MTM services on polypharmacy in PLWHA. A secondary data analysis of a new MTM project by the CDC, UNTHSC, and Walgreens that involved the collaboration of pharmacists and clinicians to provide patient-centered care for HIV patients was done. The study involved 765 participants from 10 states in the United States. Polypharmacy was measured by the number of polyactive substances (pharmacologically active ingredients) in medications used. A paired T-test was used to find the difference between the pill count and the polyactive substances in medicines used by PLWHA. A longitudinal data analysis using a generalized estimating equation was used to assess the impact of MTM intervention on polypharmacy over time by determining the change in polyactive substances in medication pre-post MTM intervention. The relationship between the changes in HIV outcomes CD4 count and HIV RNA count and the change in polyactive substances pre-post MTM intervention was also determined. The results showed a significant average difference between the polyactive substance count and the pill count of about 2.15. Also, the number of polyactive substances in medications used by study participants reduced by an average of 3 from pre- to post- MTM intervention. There was a relationship between the change in HIV outcomes and the change in polyactive substance pre-post MTM intervention. As polyactive substances decrease over time in the study, there is a higher chance that there is viral suppression and improvement in CD4 count at the end of the study. Medication therapy management involving pharmacists and clinicians may be useful in addressing polypharmacy in PLWHA. The MTM program in this study was not designed to address polypharmacy. But the results indicated that the intervention had a positive impact on polypharmacy. Further studies, such as a case-control study or a randomized control trial, are required to assess the effect of MTM on polypharmacy better.
Illicit Substance Use Among a Sample of Subsidized Housing Residents: Concordance, Longitudinal Trends, and Quality of Life
(2019-05) Rendon, Alexis; Walters, Scott T.; Spence-Almaguer, Emily; Mun, Eun-Young; Livingston, Melvin D.; Suzuki, Sumihiro
This three-paper model dissertation investigates issues related to self-reported substance use. Self-report is a less invasive and expensive method of collecting substance use behavior when compared to a toxicological test, but the self-report method has been shown to be unreliable in some populations. We found that self-report missed some use captured by a saliva toxicological test administered to a subsidized housing population enrolled in a technology-assisted health coaching program. Concordance was highest among marijuana users and increased over time. Higher rates of concordance were found when the recall window was expanded from a restricted biological recall window to match the toxicological test to the full 90 day window of the Timeline Follow-Back. Participants who reported using substances more frequently reported having more problems related to their substance use. We also found that both substance use problems and the frequency of consumption of a combined Other category of substances, including cocaine, amphetamine, methamphetamine, opiates, prescription pills, or phencyclidine were predictive of lower quality of life. This dissertation validates previous literature indicating that self-report is a fair to moderately good measure of actual substance use behavior in vulnerable populations that may intentionally or unintentionally misreport their substance use. Programs limited to self-reported measures may consider widening their recall windows to increase accuracy of self-report.
Changes in Healthcare Utilization and Charges Among Supportive Housing Residents Enrolled in a Health Coaching Program
(2019-05) Chhetri, Shlesma; Spence-Almaguer, Emily; Walters, Scott T.; Stockbridge, Erica L.; Aryal, Subhash
The effectiveness of self-management programs on healthcare use outcomes is an active area of research with inconsistent results. This study was the first to evaluate changes in healthcare utilization (including hospital encounters, inpatient visits, outpatient visits, and emergency visits) and charged amounts among supportive housing residents enrolled in a health coaching program. We utilized retrospective longitudinal medical claims data and a qualitative examination of participants' perceptions of the program's influence on their healthcare use. Zero-inflated negative binomial model and log-gamma models were used to assess change in count variables and charged amounts respectively. Although participants reported a positive impact of the program on their overall quality of life through improved health self-management strategies, the analysis of claims data showed no significant change in healthcare use and charged amounts in all analyses spanning 12 months prior to 24 months post enrollment. These findings may potentially demonstrate the success of health coaching programs in stabilizing healthcare utilization among individuals who otherwise might have increased their healthcare use over time. During interviews and focus groups, participants also shared personal and systems level challenges that influenced their healthcare use. The inclusion of a control group in future analyses would help measure the actual impact of health coaching on healthcare utilization measures among supportive housing residents with high health needs.
Latent Tuberculosis Infection Testing and Treatment in the Private Sector: Evidence from Commercial Health Insurance Claims
(2017-05) Stockbridge, Erica L.; Miller, Thaddeus L.; Carlson, Erin K.; Ho, Christine
Targeted identification and treatment of people with latent tuberculosis infection (LTBI) are key components of the US tuberculosis (TB) elimination strategy. Little research on LTBI testing and treatment has been conducted outside of public healthcare settings, so there is a dearth of information about the provision of LTBI-related services in the private sector environment. This gap was highlighted by recent health insurance-related regulatory changes that are expected to increase LTBI testing and treatment by private providers. Our research aimed to provide insight on the LTBI-related services provided to commercially insured individuals in the private sector setting. We analyzed a national sample of commercial insurance medical and pharmacy claims data from the Optum National Research Database for 4 million people ages 0 to 64; these data represented insurance-paid healthcare services received between January 2011 and December 2013 at minimum. We estimated private sector LTBI testing rates and examined patient characteristics associated with private sector LTBI testing. We also developed a claims-based method to identify LTBI treatment in the private sector and subsequently used this method to estimate treatment completion rates and identify clinical and system factors associated with treatment completion. We found that LTBI testing was not uncommon in the private sector and it is generally targeted to patients at the highest risk of TB/LTBI. Further, our claims-based method to identify and evaluate LTBI treatment successfully identified such treatment occurring in the private sector. Private sector LTBI treatment completion rates were in the range of those found in public health settings. Additionally, we identified factors unique to the private healthcare system that are associated with LTBI treatment completion. Our results suggest that the commercial sector may be a valuable adjunct to more traditional venues for TB prevention. Moreover, medical and pharmacy claims data and the claims-based methods we developed offer a means to gain important insights and open new avenues to monitor, evaluate, and coordinate TB prevention.
Investigating the Complex Relationship Between Adverse Childhood Experiences and Oral Health-Related Quality of Life
(2017-05) Kabani, Faizan A.; Lykens, Kristine A.
Dental caries is one of the most common chronic disease in children and continues to be a significant global public health concern. Evidence indicates that chronic diseases, and adverse childhood experiences (ACEs), have destructive impacts on overall quality of life, health outcomes, and health care expenditures. The ACE investigation identified cumulative dose-response relationships between ACEs and development of diverse health and social consequences later in life. Research is scarce on investigating causal pathways to facilitate contextualized public health interventions addressing this seismic threat. Data was utilized from the 2011-2012 National Survey of Children's Health, inclusive of ages 1-17 for dentate status. The dependent variables identified untreated oral health care needs and preventive dental utilization. The key independent variable, ACEs, included exposure to parental death, parental divorce, parental incarceration, mental health illnesses, domestic violence, neighborhood violence, and racial discrimination. Exogenous variables included age, sex, race/ethnicity, number of children in household, socioeconomic status proxies, health insurance status, and presence of special health care needs. Path analysis, a special subcomponent of structural equation modeling was utilized to explore direct, indirect, and mediating causal pathways. The data, when adjusted for complex survey design, proportionately represents children in the United States. The results of the adjusted logistic regressions revealed ACEs demonstrating varying magnitudes of significance across diverse racial and ethnic profiles. Exposures to parental divorce and parental death particularly exhibited critical magnitudes of influence. Adjusted path analyses demonstrated alternative family structures contributing a mediating role between ACEs and oral health-related quality of life (OHRQoL). In keeping with the Pareto Principle, exposure to certain ACEs, namely parental divorce and parental death, potentially introduces more profound social and health-related consequences later in life. Moreover, invocation of Occam's razor, can assist in theorizing that exposure to alternative family structures (i.e. via parental divorce and/or parental death) initiate a concatenated deteriorating domino effect sequela of secondary ACEs. Therefore, contextualized interventions should prioritize psychotherapeutic child, marriage, and family counseling services improving the home, as an enabling environment, to potentially minimize detriments of ACEs on OHRQoL.

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