Medicine and Health Sciences Commons^™

Diagnostics And Model Selection For Generalized Linear Models And Generalized Estimating Equations, Chelsea Boquet Deroche

Theses and Dissertations

The use of generalized linear models and generalized estimating equations in the public health and medical fields are important tools for research, specifically for modeling clinical trials, evaluating preventive measures, and secondary data analysis. It is important for these researchers to have the necessary tools to analyze and model their data correctly. This dissertation focuses on a penalized maximum likelihood estimation method for generalized linear models, measures of association such as the coefficient of determination and R² for generalized estimating equations, and a modified quasi-likelihood information criterion for generalized estimation equations.

Common problems that arise during estimation of generalized …

Smoking Cessation In Pregnancy And Gestational Weight Gain In South Carolinian Mothers, 2009-2011, Laquenta Latreese Weldon

Theses and Dissertations

Purpose: To determine if smoking cessation during pregnancy is associated with excessive gestational weight gain (GWG).

Methods: Data came from the 2009-2011 Pregnancy Risk Assessment Monitoring System (PRAMS), an ongoing population-based survey of live births in South Carolina (n=2,603). Participant smoking status was classified as nonsmoker (did not smoke before or during pregnancy), persistent smoker (smoked before and throughout pregnancy), or quitter (smoked before but quit during pregnancy). Multinomial logistic regression model was estimated to examine the association between smoking status and meeting the 2009 Institute of Medicine guidelines, while linear regression model was used for the continuous outcomes such …

Prostate Specific Antigen (Psa) Growth Curves: A Method To Improve Prostate Cancer Screening, Azza Shoaibi

Theses and Dissertations

Prostate cancer (PrCA) screening aimed at detecting aggressive disease represents a significant public health issue. Development of biomarkers to predict PrCA that is likely to kill if left untreated is a major challenge. This dissertation focused on analyzing existing repeated measures of prostatic specific antigen (PSA) to develop and validate a tool to improve both sensitivity and specificity of the PSA-based screening test to detect high-risk PrCA. We used the Prostate Lung Colorectal and Ovarian trial data (PLCO) for PSA growth model building. Using 6 years of annual PSA measurements we established the PSA growth curves for four groups of …

Interpregnancy Weight Change And Adverse Maternal Outcomes, Chelsea Lynes

Theses and Dissertations

Obesity during pregnancy is associated with a high risk of adverse maternal outcomes. Little is known about how weight change between consecutive pregnancies impacts subsequent pregnancy complications and newborn outcomes. This study aimed to explore the association between interpregnancy BMI change and adverse maternal outcomes, specifically, gestational diabetes mellitus (GDM), gestational hypertension, pre-eclampsia, non-repeat cesarean delivery (C-section), and vaginal birth after cesarean delivery (VBAC). The study sample was derived from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Consecutive Pregnancy Study, which collected data from 20 hospitals in Utah utilizing electronic medical records and International Classification …

Food Security Status And Life Events Among Households With Children In The Midlands Of South Carolina, Erin Rebekah Drucker

Theses and Dissertations

Purpose: Food insecurity is a major public health problem in the United States (US) with 14.5% of US households having experienced some level of food insecurity in 2012. Among households with children, 20% experienced low food security in 2012, and in half of these households, both the children and adults were affected. Food insecurity among children can have lifelong negative health and mental effects. Life events are defined as self-­‐reported life changes, which create a strain on resources and an opportunity for food insecurity, Methods: The Midlands Family Study (MFS) was a cross-­‐ sectional study that surveyed households …

Cluster Analysis With Batch Effect, Yifan Tang

Theses and Dissertations

Clustering, as a fundamental process in data science, is frequently used in preliminary data analysis. Batch effects are a powerful source of variation that can come from many sources in data collection, and influence data. We propose a method to simultaneously remove batch effects and perform cluster analysis. We see a batch effect as a fixed value added on to each batch, and do not make assumptions about the distribution of batch effects. We represent the data using a Gaussian mixture model, and use the EM algorithm to estimate the cluster means, the cluster covariance matrices, and the batch effects, …

Longitudinal Association Between Television Watching, Computer Use And Meal Frequency And Risk Markers In Diabetes Among Youth With Diabetes, Chao Li

Theses and Dissertations

BACKGROUND AND OBJECTIVES: Television watching and computer use are considered to be the main sedentary behaviors in children and youth. However, their longitudinal impact on HbA1c and serum lipids among youth with type 1 diabetes (T1D) and type 2 diabetes (T2D) are under-studied. Sedentary behavior is normally assessed by questionnaire in large epidemiological studies, however, its measurement by questionnaire has not been evaluated among youth with diabetes. Also, no recent studies have evaluated the optimal meal frequency for glycemic control in youth with T1D and T2D; for this reason nutritional guidelines on meal frequency for youth with diabetes are vague. …

Exploring The Association Between Network, Cognitive, Structural Social Capital And The Risk Of Clinical Depression In Taiwan, Yun-Hsuan Wu

Theses and Dissertations

Depression is the one of most common mental health conditions in Taiwan. Although evidence suggests that social capital is associated with depression, few studies have comprehensively explored the influence of social capital on depression. Also evidence in Taiwan is limited in comparison to other Western countries. Data from the 1997 Taiwan Social Change Survey (n=2,598), which is the only dataset that contains the best available information to measure and compare all three dimensions of social capital (network, cognitive, and structural social capital), were used to examine the association between three dimensions of neighborhood- and individual-level social capital and depression among …

The Relationship Of The Mediterranean Diet And The Dietary Approaches To Stop Hypertension (Dash) Style Diet With Cardiometabolic Health, Yong-Moon Park

Theses and Dissertations

Introduction: Much evidence shows that the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) style diet are associated with risk reduction of cardiometabolic disease as well as lower risk of all-cause, cardiovascular disease (CVD), and cancer mortality. A subgroup of obese individuals (metabolically healthy obese (MHO) phenotype) and normal weight individuals (metabolically obese normal weight (MONW) phenotype) have been identified to have different cardiometabolic risks compared with their counterparts in the same category of body mass index (BMI). Scarce evidence exists demonstrating a relationship between adherence to Mediterranean diet or DASH style diets with MHO and MONW …

Environmental Exposures And Childhood Pulmonary Function, Pallavi Prakash Balte

Theses and Dissertations

Fetal origins of adult disease hypothesis states that adverse influences early in developmental period and particularly during intrauterine life can result in permanent changes in physiology which may lead to increased disease risk of chronic diseases in adulthood. Both fetal and adolescent period are critical time periods for development of lungs. Any adverse environmental exposures during these critical periods of lung growth is a form of programming which can have long term effects on pulmonary function. The purpose of this dissertation was to examine the association between different environmental exposures and pulmonary function in children and late adolescents. The first …

Maternal Obesity, Gestational Weight Gain And Offspring’S Asthma, Kristen Polinski

Theses and Dissertations

Introduction: Obesity is common among women of childbearing age and intrauterine exposures may influence the development of early childhood asthma. A handful of studies have investigated pre-pregnancy obesity, but even fewer have thoroughly explored gestational weight gain as possible childhood asthma risk factors. Gaps remain in the literature and to our knowledge, none have longitudinally explored these relationships in a nationally representative sample of U.S. children.

Methods: We used data from the Early Childhood Longitudinal Study – Birth Cohort, in which children were followed through age four (n≈5,200). Asthma was based on parent report of a physician’s diagnosis. …

Soil Arsenic And Lead Concentrations And Preterm Birth: Investigating Racial Disparities, Sources, Neighborhood Effects, And Spatial Patterns, Pamela Harley Thornton Davis

Theses and Dissertations

Preterm birth, generally defined as birth at <37 weeks of gestation, is an important public health issue that has multiple risk factors related to characteristics of both the mother and her environment. The purpose of this dissertation was to examine potential sources of spatially interpolated (kriged) environmental concentrations of arsenic (As) and lead (Pb) in residential soils and preterm birth in a Medicaid population of mothers giving birth in South Carolina (SC) from 1996-2001. The first objective was to investigate if a racial disparity existed for estimated soil As and Pb concentrations, after adjusting for proximal and distal sources of these metals (including distance and direction to industrial facilities) in a subset of SC Medicaid mothers living in areas of SC where soil samples were collected and analyzed for these metals. The second objective was to test the hypothesis that estimated soil As and Pb concentrations were associated with increased odds of early (<34 weeks) and late (34-36 weeks) preterm births in the same subset of SC Medicaid mothers, after adjusting for individual and neighborhood level risk factors, and examine if measure of neighborhood deprivation and racial residential segregation modified these associations. The third objective was to examine if early and all preterm births, aggregated at the county level, varied spatially and/or temporally in SC for all Medicaid mothers giving birth from 1996-2001 in Bayesian models.

For the first objective, black mothers had significantly higher estimated As and Pb soil concentrations than white mothers in the study population (adjusted betas were 0.12 and 0.22 for As and Pb, respectively; all p<0.006), and proximal sources of metals (e.g., percent of Census block group are covered by roads) were more strongly associated with estimated soil As and Pb concentrations than composite As and Pb releases from industrial facilities categorized by distance from and direction to Census block groups in which maternal residences were located.

For the second objective, estimated soil concentration of neither As nor Pb were associated with increased odds of early or late preterm birth after adjusting for maternal and neighborhood level risk factors. Only individual level covariates were associated with these birth outcomes, and associations were stronger for early as compared to late preterm births. Neighborhood deprivation and racial …

Geographic Accessibility To Health Services And Neonatal Mortality Among Very Low Birthweight Infants In South Carolina, Portavia Featherstone

Theses and Dissertations

Introduction: Infant mortality is commonly denoted as a marker of population health with more than half of all infant deaths occurring during the neonatal period (0-27 days) of infancy. Mortality for infants born very low birthweight (<1500 grams) is markedly higher than the babies born with normal birthweight (2500-4000 grams). The purpose of this research project was to assess geographic access to perinatal health services and the risk of neonatal death among infants born with very low birth weight. Data and methods: The linked birth and death records of a retrospective cohort of very low birthweight (<1500 grams) infants born in South Carolina between the years 2010 and 2012 were used (n=3191). We assessed the impact of travel time from maternal residence to delivery hospital and travel time from maternal residence to the nearest prenatal care provider (obstetricians/gynecologists, community health center, or rural health clinic). Logistic regression modeling was performed with adjustments for maternal characteristics (race, age, chronic/gestational hypertension, chronic/gestational diabetes mellitus, smoking, prenatal care), newborn characteristics (gestational age, birthweight, gender, NICU admission at birth), and the birth in a level III hospital. Results: There were a total of 563 neonatal deaths in this population and the neonatal mortality rate was 17.64 neonatal deaths per 100 live births. We did not find significant associations of travel time from maternal residence to delivery hospital and to a closest prenatal care provider with neonatal death after adjusting for confounders. However, we found that a one-week increase in gestational age (OR: 0.61 [95% CI: 0.57-0.65]) and non-Hispanic Black mothers (versus non-Hispanic White mothers) (OR: 0.65 [95% CI: 0.45-0.94]), were associated with the lower odds of neonatal death, while non-NICU admission at birth (OR: 5.99 [95% CI: 4.05-8.84]) was associated with an increased odds of neonatal death. Conclusion: Although we did not find that travel time was associated with neonatal mortality among very low birthweight infants, our study identified a few significant correlates for neonatal deaths in this birthweight group. Future studies should investigate the role of geographic access to care on mortality during other periods of infancy and among other birthweight groups.

Effect Of Primary Care Physician Density On Late Stage Cervical Cancer Diagnosis, Emily Haanschoten

Theses and Dissertations

INTRODUCTION: Late-stage cervical cancer diagnosis is an important contributing factor to the cervical cancer mortality rate. Screening for cervical cancer is a vital tool in reducing the number of late-stage cases, preventing incident cases and reducing mortality. Access to care is often a significant barrier to receiving these services. Women who have no usual source of care report significantly lower percentages of Pap tests than women who have a usual source. South Carolina ranks 13th in the US in cervical cancer incidence and 7th in cervical cancer mortality. South Carolina also struggles with a primary care physician shortage, ranking 39th …

Gestational Weight Gain, Pregnancy Outcomes, And Use Of Perinatal Health Services, Lujing Zhan

Theses and Dissertations

This dissertation consists of three studies that were undertaken to better understand 1) the role of gestational weight gain (GWG) during early pregnancy on subsequent blood pressure changes and the risk of pregnancy-induced hypertension (PIH), 2) the causal effect of GWG in both early and mid-late pregnancy on the subtypes of preterm births, and 3) the impact of personal capital on the use of perinatal health services (i.e., prenatal care use and preconception care counseling). The first two studies were based on the data from the 1988 National Maternal and Infant Health Survey and the third study employed the data …

Examining The Influence Of Healthy Eating Identity On Shopping Behaviors, Jordan Brittingham

Theses and Dissertations

Eating identity is shown to be a promising measure capable of enhancing our understanding of nutrition behavior. Persons with healthy eating identities are less likely to consume the typical American diet and report healthier diets in general. While there are several studies linking healthy eating identity and diet, there is currently no research examining healthy eating identity in relation to food shopping behavior, an important aspect of nutritional intake. The purpose of this study was to examine the influence of healthy eating identity on shopping behaviors including supermarket utilization, supercenter utilization, likelihood of shopping at the nearest store, distance to …

Periodontal Microorganisms, Obesity, Chronic Inflammation, And Type 1 Diabetes, Georges Joseph Nahhas

Theses and Dissertations

Periodontal disease is a low-grade chronic inflammation in the tissues surrounding the teeth caused by multiple, mostly gram-negative pathogens. It is associated with diabetes, obesity, and chronic inflammation. The specific roles that periodontal microorganism play in these conditions are not well-studied. Hereby, we explored how periodontal bacteria from sub gingival plaque clustered in youth with and without type 1 diabetes, and how such patterns related to body-mass-index percentile (BMI percentile), C-reactive protein (CRP) and adiponectin. Cross-sectional data were collected from 105 youth with type 1 diabetes and 71 without diabetes. Participants were between 12 and 19 years of age receiving …

Single Nucleotide Polymorphisms In Dna Repair And Oxidative Stress Genes, And Their Interaction With Antioxidants On Prostate Cancer Aggressiveness, Samuel Antwi

Theses and Dissertations

Prostate cancer is the leading invasive malignancy and the second most common cause of cancer death among American men. Despite compelling evidence that oxidative stress, ineffective DNA damage repair, and habitually low antioxidants intake may act in tandem to influence prostate carcinogenesis, few studies have examined gene-diet interactions involving these risk factors. Even fewer studies have examined such interactions in relation to prostate cancer aggressiveness. This study investigated whether single nucleotide polymorphisms (SNPs) in DNA repair- and oxidative stress-related genes modulated associations between antioxidant intake and prostate cancer aggressiveness. We utilized data from the North Carolina-Louisiana Prostate Cancer Project (PCaP) …

Exploring The Association Between Depression And Obesity Among Alzheimer's Patients, Stephanie Clugstone

Theses and Dissertations

Alzheimer’s disease (AD) is a neurological disorder that affects elderly individuals, and is becoming an increasing concern among the aging population of the world. Due to the projected increase in incidence of AD, modifiable risk factors such as depression and obesity should be evaluated, as prevention is the only current option. This study aimed to determine the prevalence of obesity and depression among AD patients, and to evaluate the association between depression and obesity. Patients were chosen from a subset of the South Carolina Alzheimer’s disease registry, which included information about weight status and depression, as well as several other …

Hepatitis B, C Virus And Hiv Co-Infection Among Reported Female Cases In South Carolina, 2004 - 2011: An Epidemiological Analysis Of Pregnancy Outcomes, Afiba Manza-Azele Agovi

Theses and Dissertations

HIV, hepatitis B and C virus (HBV, HCV) are three of the most common blood-borne infections and they continue to be a major public health problem in the United States (US) and globally. It is not well understood if maternal infection with either HBV or HCV has an adverse impact on pregnancy outcomes as findings from previous studies have provided some mixed results. The overall goal of this study was to assess the risk of preterm birth, low birth weight (LBW), small for gestational age (SGA) and admission into neonatal intensive care unit (NICU) for babies born to HBV- and …

Associations Between The Perceived And Built Food Environment, Timothy L. Barnes

Theses and Dissertations

Neighborhood food environments have been associated with dietary intake and obesity. Measures of the food environment have typically been characterized with geographic information systems (GIS)-based measures, however, the use of perception-based measures of the food environment have increased in frequency. Few studies have fully examined the relationship between perceptions and GIS-based measures of the food environment, especially considering the congruency between perceived and GIS-based presence of specific retail food outlets, nor the relationship between food outlets and perceived availability of healthy foods or fast food opportunities.

Telephone survey data from 705 residents in an eight-county region of South Carolina were …

Geographical Proximity To Health Facilities And Breast Cancer Morbidity And Mortality Among Women In South Carolina's Best Chance Network, Leepao Khang

Theses and Dissertations

Death rates for breast cancer have steadily decreased in women due to early detection, such as mammography, and improved treatments. Despite the benefit of mammography, many women are not up-to-date on screening and do not receive timely follow-up after abnormal mammogram finding. Breast cancer is a major contributor to morbidity and mortality among women in South Carolina. To reduce the disproportionate burden of breast cancer and cervical cancer among women in South Carolina, the South Carolina Best Chance Network (BCN) was established to provide service delivery and ensures timely and complete diagnostic follow-up and treatment initiation for underserved women.

The …

A Preliminary Study Exploring Racial Differences In Triage, Hospitalization Status, And Discharge Medication In An Emergency Department In Graniteville, Sc, Clare Pollock

Theses and Dissertations

Purpose

This study seeks to identify any racial differences present in assigned triage scores, hospitalization status and discharge medications in a rural hospital likely experiencing a surge after a mass casualty incident involving chlorine gas as a result of a train derailment. Differences were examined between Non-Hispanic White and African American adults who were moderately ill and who presented to the emergency department of the closest hospital to the accident site within 24 hours of the incident.

Methods

Non-Hispanic White and African American adults who presented to the emergency department of the closest hospital to the accident site and who …

Food Environment And Birth Outcomes In South Carolina, Xiaoguang Ma

Theses and Dissertations

An increasing number of studies examined the association between neighborhood characteristics and birth outcomes. However, the results can be difficult to compare because of the variety of indicators used to characterize the neighborhood. As an important neighborhood characteristic, the food environment is associated with residents' nutrition status, diet quality, and related health outcomes. In addition, the food environment has been found to influence women's diet quality during pregnancy, which is a key factor in predicting birth outcomes. However to date, studies on food environment and birth outcomes are extremely limited.

This study examined the association between food environment (evaluated by …

Illness-Related Diabetes Social Support And Glycemic Control Among Middle Aged And Older Adults, Favel Leah Mondesir

Theses and Dissertations

Objective

The objective of this study is to investigate the association between illness-related diabetes social support (IRDSS) and glycemic control (GC) among a racially diverse sample of middle aged and older adults. In gender-stratified models we examine whether the relationship between IRDSS and GC is modified by race/ethnicity. Additionally, we explore the association between eight individual types of IRDSS and GC.

Methods

We used the Health and Retirement Study (HRS) 2002 and the 2003 Diabetes Survey. The final analytic sample consisted of 914 study respondents. Gender-stratified multivariable logistic regression models were used to calculate odd ratios (ORs) and 95% confidence …

Association Between Breastfeeding And Infant Growth: A Probable Reverse Causality, Shraddha Vyas

Theses and Dissertations

Background: Much conflicting results exist in the association between breastfeeding and infant growth. One of these confusions is related to the temporal sequence between breastfeeding practice and infant growth.

Objective: This study aimed at examining the association and investigating a possible reverse causality between breastfeeding and infant growth.

Method: Infant Feeding Practices Survey II, a national longitudinal database with repeated measurements, following women prenatally and until one year postpartum (N=2914) was used. Mixed linear model assessed the impact of breastfeeding from the 2nd, 4th, 6th and 9th months on infant growth at the 3rd, 5th, 7th and 12th months, respectively. …