Biostatistics Commons^™

Evaluation And Lessons Learned From The Dissemination And Implementation Science Scholars Program In The National Cancer Prevention And Control Research Network, Daniela B. Friedman, Cam Escoffery, Elaine H. Morrato, Cynthia A. Thomson, Courtney N. Petagna, Freda Allyson Hucek, Mary Wangen, Aubrey Villalobos, James R. Hébert Scd, Samuel Noblet, Mayank Sakhuja, David O. Garcia, Jennifer L. Cruz, Stephanie B. Wheeler

Faculty Publications

Background:

The Centers for Disease Control and Prevention (CDC)-funded Cancer Prevention and Control Research Network (CPCRN) has been a leader in cancer-related dissemination & implementation (D&I) science. Given increased demand for D&I research, the CPCRN Scholars Program launched in 2021 to expand the number of practitioners, researchers, and trainees proficient in cancer D&I science methods. Methods:

The evaluation was informed by a logic model and data collected through electronic surveys. Through an application process (baseline survey), we assessed scholars’ competencies in D&I science domains/subdomains, collected demographic data, and asked scholars to share proposed project ideas. We distributed an exit survey …

Exploring The Association Between Parenting Stress And A Child’S Exposure To Positive Childhood Experiences (Pces), Elizabeth Crouch Ph.D., Elizabeth Radcliff, Monique J. Brown Ph.D., Mph, Peiyin Hung Ph.D

Faculty Publications

High levels of parenting stress, defined as a caregiver or parent feeling stress or aggravation from parenting, has been previously shown to be associated with an increased likelihood of neglect, child maltreatment, and household dysfunction: adverse childhood experiences (ACEs). Despite the potential mitigation of positive childhood experiences (PCEs) on ACEs, prior studies on the increased likelihood of a child experiencing ACEs due to parenting stress have left a critical question unanswered: whether high parenting stress may decrease a child’s likelihood of experiencing PCEs. We analyzed the 2019–2020 National Survey of Children’s Health to examine whether higher levels of parenting stress …

Social Isolation And Loneliness Prevention Among Rural Older Adults Aging-In-Place: A Needs Assessment, Jodi L. Southerland, Shimin Zheng, Kayla Dodson, Erin Mauck, Juanita-Dawne R. Bacsu, Monique J. Brown Ph.D., Mph, Jeremy Holloway, Steffi M. Kim, Ayse Malatyali, Matthew Lee Smith

Faculty Publications

Introduction: The adverse effects of social isolation and loneliness (SI/L) have been documented among older adults in rural communities and contribute to poor health outcomes, premature disability and mortality, and increased burden on the healthcare system. The identification of factors contributing to SI/L among older adults can build the foundation for rural policymakers and leaders to allocate resources and develop tailored strategies more efficiently. The purpose of this article is to describe findings from a needs assessment designed to understand local factors that contribute to SI/L among rural older adults in a county in Northeast Tennessee. Findings from the needs …

Reframing And Advancing Academic Mentorship To Support New And Early Career Faculty Members, Juanita-Dawne R. Bacsu, Patricia C. Heyn, Steffi Kim, Zahra Rahemi, Monique J. Brown, Darina V. Petrovsky, Justine S. Sefcik, Jodi L. Southerland, Jeremy Holloway, Elyse Couch, Ayse Malatyali, Matthew L. Smith

Faculty Publications

Mentorship is critical to fostering professional growth and career development in academia. However, academic mentorship is often an informal activity that is overlooked and under researched. There is much ambiguity and uncertainty surrounding mentorship roles and strategies in academia. This paper provides recommendations and strategies to reframe and advance academic mentorship to support new and early career faculty.

Allura Red Ac Is A Xenobiotic. Is It Also A Carcinogen?, Lorne J. Hofseth Ph.D., James Hébert Scd, Elizabeth Angela Murphy, Erica Trauner, Athul Vikas, Quinn Harris, Alexander A. Chumanevich

Faculty Publications

Merriam-Webster and Oxford define a xenobiotic as any substance foreign to living systems. Allura Red AC (a.k.a., E129; FD&C Red No. 40), a synthetic food dye extensively used in manufacturing ultra-processed foods and therefore highly prevalent in our food supply, falls under this category. The surge in synthetic food dye consumption during the 70s and 80s was followed by an epidemic of metabolic diseases and the emergence of early-onset colorectal cancer in the 1990s. This temporal association raises significant concerns, particularly given the widespread inclusion of synthetic food dyes in ultra-processed products, notably those marketed toward children. Given its interactions …

Allura Red Ac Is A Xenobiotic. Is It Also A Carcinogen?, Lorne J. Hofseth, James R. Hébert Scd, Elizabeth Angela Murphy, Erica Trauner, Athul Vikas, Quinn Harris, Alexander A. Chumanevich

Faculty Publications

Merriam-Webster and Oxford define a xenobiotic as any substance foreign to living systems. Allura Red AC (a.k.a., E129; FD&C Red No. 40), a synthetic food dye extensively used in manufacturing ultra-processed foods and therefore highly prevalent in our food supply, falls under this category. The surge in synthetic food dye consumption during the 70s and 80s was followed by an epidemic of metabolic diseases and the emergence of early-onset colorectal cancer in the 1990s. This temporal association raises significant concerns, particularly given the widespread inclusion of synthetic food dyes in ultra-processed products, notably those marketed toward children. Given its interactions …

Simulation Study On Count Data Based On Double Poisson Distribution, Chao Ma

Theses and Dissertations

This thesis delves into the double Poisson distribution. Regression based on the double Poisson distribution, as proposed by Efron in 1986, offers an alternative approach that allows for more accurate regression models when dealing with discrete data that exhibit either over- or under-dispersion compared to the Poisson distribution. In this thesis, two methods of calculating the exact double Poisson density are compared: one utilizes the exact probability with the normalizing constant c(mu, theta) by definition or the “finite sum” method, while the other employs an approximation of the normalizing constant c(mu, theta). Furthermore, a simulation was …

Interpregnancy Interval And Adverse Perinatal Outcomes: A Within-Individual Comparative Method, Maria Sevoyan, Marco Geraci, Edward A. Frongillo, Jihong Liu, Nansi S. Boghossian

Faculty Publications

Background and Aim: Previously observed associations between interpregnancy interval (IPI) and perinatal outcomes using a between-individual method may be confounded by unmeasured maternal factors. This study aims to examine the association between IPI and adverse perinatal outcomes using within-individual comparative analyses. Methods: We studied 10,647 individuals from the National Institute of Child Health and Human Development Consecutive Pregnancies Study in Utah with ≥3 liveborn singleton pregnancies. We matched two IPIs per individual and used conditional logistic regression to examine the association between IPI and adverse perinatal outcomes, including preterm birth (PTB, < 37 weeks’ gestation), small-for-gestational-age (SGA, < 10th percentile of sex-specific birthweight for gestational age), low birthweight (LBW, < 2,500 g), and neonatal intensive care unit (NICU) admission. Point and 95% confidence interval (CI) estimates were adjusted for factors that vary across pregnancies within individuals. Results: CIs did not unequivocally support either an increase or a decrease in the odds of PTB (adjusted odds ratio [aOR]: 1.31, 95% CI: 0.87, 1.96), SGA (aOR: 0.81, 95% CI: 0.51, 1.28), LBW (aOR: 1.59, 95% CI: 0.90, 2.80), or NICU admission (aOR: 0.96, 95% CI: 0.66, 1.40) for an IPI < 6 months compared to 18–23-months IPI (reference), and neither did the CIs for the aOR of IPIs of 6–11 and 12–18 months compared to the reference. In contrast, an IPI ≥24 months was associated with increased odds of LBW (aOR: 1.66, 95% CI: 1.03, 2.66 for 24–29 months; aOR: 2.27, 95% CI: 1.21, 4.29 for 30–35 months; and aOR: 2.09, 95% CI: 1.17, 3.72 for ≥36 months). Conclusions: Using a within-individual comparative method, we did not find evidence that a short IPI compared to the recommended IPI of 18–23 months was associated with increased odds of PTB, SGA, LBW, and NICU admission. IPI ≥ 24 months was associated with increased odds of delivering an LBW infant.

Childhood Sexual Abuse And Compulsive Sexual Behavior Among Men Who Have Sex With Men Newly Diagnosed With Hiv, Monique J. Brown, Medinat Omobola Osinubi, Daniel Amoatika, Mohammad Rifat Haider, Sally Kirklewski, Patrick Wilson, Nathan B. Hansen

Faculty Publications

Childhood sexual abuse (CSA) continues to be a public health challenge. The prevalence of experiencing CSA is higher among men who have sex with men (MSM) than the general population. CSA has been linked to compulsive sexual behavior (CSB) among varying populations but has not been examined among MSM who were newly diagnosed with HIV. Therefore, the aims of this study were to assess the direct association between CSA and CSB among newly diagnosed MSM living with HIV, and to identify the potential mediating roles of depressive symptoms and emotion regulation in the association between CSA and CSB. The study …

Advancing Objective Mobile Device Use Measurement Inchildren Ages 6–11 Through Built-In Device Sensors: A Proof-Of-Concept Study, Olivia L. Finnegan, Robert Glenn Weaver Med, Phd, Hongpeng Yang, James W. White, Srihari Nelakuditi, Zifei Zhong, Rahul Ghosal Ph.D., Yan Tong, Aliye B. Cepni, Elizabeth L. Adams, Sarah Burkart Mph, Ph.D., Michael W. Beets Med, Mph, Phd, Bridget Armstrong Ph.D.

Faculty Publications

Mobile devices (e.g., tablets and smartphones) have been rapidly integrated into the lives of children and have impacted howchildren engage with digital media. The portability of these devices allows for sporadic, on-demand interaction, reducing theaccuracy of self-report estimates of mobile device use. Passive sensing applications objectively monitor time spent on a givendevice but are unable to identify who is using the device, a significant limitation in child screen time research. Behavioralbiometric authentication, using embedded mobile device sensors to continuously authenticate users, could be applied toaddress this limitation. This study examined the preliminary accuracy of machine learning models trained on iPad …

Perspective—Surface-Display Techniques In Electrochemical Biosensor Designs For Health Monitoring, Courtney J. Weber, Megan D. Whisonant, Olivia M. Clay, Olja Simoska

Faculty Publications

Enzymatic and microbial electrochemical biosensors integrate enzymes and microorganisms as biological recognition elements into the sensor design and functionality. Enzyme-based sensors offer high sensitivity and selectivity for target analyte detection. However, these have limited stability necessary for continuous analyte monitoring. Contrarily, microbe-based electrochemical sensors provide a means for continuous analyte sensing but are associated with challenges related to analyte selectivity in complex samples. To address these limitations, surface-display methods, which bind enzymes to microbial surfaces, enhance biosensor selectivity and sensitivity. This perspective outlines the application of surface-display techniques, offering a promising avenue for health monitoring.

Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternal-Infant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella Coker Watson Self Ph.D., Ms, Berry A. Campbell, Melissa Nolan Ph.D., Mph

Faculty Publications

Toxoplasma gondii is a parasitic infection that can be transmitted in utero, resulting in fetal chorioretinitis and other long-term neurological outcomes. If diagnosed early, pregnancy-safe chemotherapeutics can prevent vertical transmission. Unfortunately, diagnosis of acute, primary infection among pregnant women remains neglected, particularly in low-and-middle-income countries. Clinically actionable diagnosis is complex due to the commonality of infection during childhood and early adulthood which spawn long-last antibody titers and historically unreliable direct molecular diagnostics. The current study employed a cross-sectional T. gondii perinatal surveillance study using digital PCR, a next generation molecular diagnostic platform, and a maternal-fetal outcomes survey to ascertain …

Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternalinfant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella C.W. Self Ph.D., Ms, Berry A. Campbell, Melissa S. Nolan Ph.D., Mph

Faculty Publications

Toxoplasma gondii is a parasitic infection that can be transmitted in utero, resulting in fetal chorioretinitis and other long-term neurological outcomes. If diagnosed early, pregnancysafe chemotherapeutics can prevent vertical transmission. Unfortunately, diagnosis of acute, primary infection among pregnant women remains neglected, particularly in low-andmiddle-income countries. Clinically actionable diagnosis is complex due to the commonality of infection during childhood and early adulthood which spawn long-last antibody titers and historically unreliable direct molecular diagnostics. The current study employed a cross-sectional T. gondii perinatal surveillance study using digital PCR, a next generation molecular diagnostic platform, and a maternal-fetal outcomes survey to ascertain the …

Maternal Care Utilization And Provision During The Covid-19 Pandemic: Voices From Minoritized Pregnant And Postpartum Women And Maternal Care Providers In Deep South, Ran Zhang, Tiffany Byrd, Shan Qiao Ph.D., Myriam E. Torres Phd, Msph, Xiaoming Li Ph.D., Jihong Liu Sc.D.

Faculty Publications

Background

The COVID-19 pandemic has significantly affected maternal care services especially for minoritized individuals, creating challenges for both service users (i.e., African American and Hispanic pregnant/postpartum women) and maternal care providers (MCPs). Guided by a socioecological framework, this study aims to investigate the experiences of African American and Hispanic pregnant and postpartum women, as well as MCPs, in accessing and providing maternal care services during the COVID-19 pandemic in the Deep South.

Methods

We conducted semi-structured interviews with 19 African American women, 20 Hispanic women, and 9 MCPs between January and August 2022. Participants were recruited from Obstetrics and Gynecology …

Identifying Multilevel Predictors Of Behavioral Outcomes Like Park Use: A Comparison Of Conditional And Marginal Modeling Approaches, Marilyn E. Wende, S. Morgan Hughey, Alexander C. Mclain, Shirelle Hallum, J. Aaron Hipp, Jasper Schipperijn, Ellen W. Stowe, Andrew T. Kaczynski Ph.D.

Faculty Publications

This study compared marginal and conditional modeling approaches for identifying individual, park and neighborhood park use predictors. Data were derived from the ParkIndex study, which occurred in 128 block groups in Brooklyn (New York), Seattle (Washington), Raleigh (North Carolina), and Greenville (South Carolina). Survey respondents (n = 320) indicated parks within one half-mile of their block group used within the past month. Parks (n = 263) were audited using the Community Park Audit Tool. Measures were collected at the individual (park visitation, physical activity, sociodemographic characteristics), park (distance, quality, size), and block group (park count, population density, age structure, racial …

Identifying A Group Of Factors Predicting Cognitive Impairment Among Older Adults, Longgang Zhao, Yuan Wang, Eric Mishio Bawa, Zichun Meng, Jingkai Wei, Sarah Newman-Norlund, Tushar Trivedi, Hatice Hasturk, Roger Newman-Norlund, Julius Fridriksson Ph.D., Anwar T. Nerchant

Faculty Publications

Background

Cognitive impairment has multiple risk factors spanning several domains, but few studies have evaluated risk factor clusters. We aimed to identify naturally occurring clusters of risk factors of poor cognition among middle-aged and older adults and evaluate associations between measures of cognition and these risk factor clusters.

Methods

We used data from the National Health and Nutrition Examination Survey (NHANES) III (training dataset, n = 4074) and the NHANES 2011–2014 (validation dataset, n = 2510). Risk factors were selected based on the literature. We used both traditional logistic models and support vector machine methods to construct a composite score …

Associations Between Sleep Duration, Sleep Disturbance And Cardiovascular Disease Biomarkers Among Adults In The United States, Prince Nii Ossah Addo, Paddington T. Mundagowa, Longgang Zhao, Mufaro Kanyangarara, Monique J. Brown Ph.D., Mph, Jihong Liu Sc.D.

Faculty Publications

Background

Sleep problems are associated with abnormal cardiovascular biomarkers and an increased risk of cardiovascular diseases (CVDs). However, studies investigating associations between sleep problems and CVD biomarkers have reported conflicting findings. This study examined the associations between sleep problems and CVD biomarkers in the United States.

Methods

Data were from the National Health and Nutrition Examination Survey (NHANES) (2007–2018) and analyses were restricted to adults ≥ 20 years (n = 23,749). CVD biomarkers [C-reactive Protein (CRP), low-density lipoproteins, high-density lipoproteins (HDL), triglycerides, insulin, glycosylated hemoglobin (HbA1c), and fasting blood glucose] were categorized as abnormal or normal using standardized cut-off …

Comparison Of Raw Accelerometry Data From Actigraph, Apple Watch, Garmin, And Fitbit Using A Mechanical Shaker Table, James W. White Iii, Olivia L. Finnegan, Nick Tindall, Srihari Nelakuditi, David E. Brown Iii, Russell R. Pate Ph.D., Gregory J. Welk, Massimiliano De Zambotti, Rahul Ghosal, Yuan Wang, Sarah Burkart, Elizabeth L. Adams, Mvs Chandrashekhar, Bridget Armstrong, Michael W. Beets, Robert Weaver Med, Phd

Faculty Publications

The purpose of this study was to evaluate the reliability and validity of the raw accelerometry output from research-grade and consumer wearable devices compared to accelerations produced by a mechanical shaker table. Raw accelerometry data from a total of 40 devices (i.e., n = 10 ActiGraph wGT3X-BT, n = 10 Apple Watch Series 7, n = 10 Garmin Vivoactive 4S, and n = 10 Fitbit Sense) were compared to reference accelerations produced by an orbital shaker table at speeds ranging from 0.6 Hz (4.4 milligravity-mg) to 3.2 Hz (124.7mg). Two-way random effects absolute intraclass correlation coefficients (ICC) tested inter-device reliability. …

Cancer Survivorship And Subjective Cognitive Decline In The Us: Results From A Nationally Representative Sample, Monique J. Brown, Ally Hucek, Jingkai Wei, Loretta Anderson, Muzi Na

Faculty Publications

Cancer may be associated with objective cognitive decline. However, studies examining the link between cancer and subjective cognitive decline (SCD), which occurs earlier during cognitive trajectories, are lacking. In addition, research assessing risk factors for SCD among cancer survivors is scant. Therefore, this study aimed to examine the association between cancer and SCD in the past year, and assess the association between age of diagnosis, cancer treatment, and SCD among cancer survivors. Data were obtained from the 2021 Behavioral Risk Factor Surveillance System (N=15,447). Crude and adjusted logistic regression models, controlling for sociodemographic characteristics, were used to determine the association …

Dual Barriers: Examining Digital Access And Travel Burdens To Hospital Maternity Care Access In The United States, 2020, Peiyin Hung Ph.D., Marion Granger, Nansi Boghossian, Jiani Yu, Sayward Harrison, Jihong Liu Sc.D., Berry A. Campbell, Bo Cai Ph.D., Chen Liang, Xiaoming Li Ph.D.

Faculty Publications

Policy Points The White House Blueprint for Addressing the Maternal Health Crisis report released in June 2022 highlighted the need to enhance equitable access to maternity care. Nationwide hospital maternity unit closures have worsened the maternal health crisis in underserved communities, leaving many birthing people with few options and with long travel times to reach essential care. Ensuring equitable access to maternity care requires addressing travel burdens to care and inadequate digital access. Our findings reveal socioeconomically disadvantaged communities in the United States face dual barriers to maternity care access, as communities located farthest away from care facilities had the …

Geographic Differences In The Magnitude Of Black-White Disparities In Having Obesity, Steven A. Cohen, Monique J. Brown, Furong Xu, Caitlin C. Nash, Mary L. Greaney

Faculty Publications

Background

Obesity disparities in the United States are well documented, but the limited body of research suggests that geographic factors may alter the magnitude of these disparities. A growing body of evidence has identified a “rural mortality penalty” where morbidity and mortality rates are higher in rural than urban areas, even after controlling for other factors. Black-White differences in health and mortality are more pronounced in rural areas than in urban areas.

Objective

Therefore, the purpose of this study was to explore how rural-urban status and region moderate Black-White health disparities in obesity.

Methods

Data were abstracted from the 2012 …

Approaches To Detecting And Modeling Over-And Underdispersion In Alternative Count Data Distributions And An Application Of Logistic Regression And Random Forest Modeling To Improve Screening Tools For Tic Disorders In Children, Rebecca C. Wardrop

Theses and Dissertations

This dissertation focuses on theory and application of discrete data methods, particularly approaches to over- and underdispersion relative to the Poisson distribution and an application of random forest and logistic regression modeling. The first chapter derives a score test for over- and underdispersion in the heaped generalized Poisson distribution. Equi-, over-, and underdispersed heaped generalized Poisson and heaped negative binomial data are simulated to evaluate the performance of the score test by comparing the power it achieves to that of Wald and likelihood ratio tests. We find that the score test we derive performs comparably to both the Wald and …

Statistical Methods For Single Cell Sequencing Data Analysis, Fei Qin

Theses and Dissertations

The recent emergence of single cell sequencing (SCS) technology has provided us with single-cell DNA or RNA sequencing (scDNA/RNA-seq) information to investigate cellular evolutionary relationships. Despite many analysis methods have been developed to infer intra-tumor genetic heterogeneity, cluster cellular subclones, detect genetic mutations, and investigate spatially variable (SV) genes, exploring SCS data remains statistically challenging due to its noisy nature.

To identify subclones with scDNA-seq data, many existing studies use an independent statistical model to detect copy number profile in the first step, followed by classical clustering methods for subclone identification in downstream analyses. However, spurious results might be generated …

A Bayesian Spatial Scan Statistic For Normal Data, Laasya Velamakanni

Theses and Dissertations

Scan statistics are useful methods for detecting spatial clustering. While they were initially developed to detect regions with an excess of binomial or Poisson events, spatial scan statistics have been extended to detect hotspots in other types of data including continuous data. They have many applications in different fields such as epidemiology (e.g. detecting disease outbreaks), sociology (e.g. detecting crime hotspots), and environmental health (e.g. detecting high-pollution areas). Spatial scan statistics identify a ‘most likely cluster’ and then use a likelihood ratio test to determine if this cluster is statistically significant. Spatial scan statistics have been extended to the Bayesian …

Ten‐Year Cardiovascular Disease Risk Score And Cognitive Function Among Older Adults: The National Health And Nutrition Examination Survey 2011 To 2014, Jingkai Wei, Hanzhang Xu, Angela D. Liese, Anwar T. Nerchant Sc.D, Mph, Dmd, Liang Wang, Chih-Hsiang Yang, Matthew C. Lohman, Monique J. Brown Ph.D., Mph, Tiansheng Wang, Daniela B. Friedman Ph.D.

Faculty Publications

BACKGROUND: The Framingham 10-year cardiovascular disease risk score, which is based on age, sex, smoking, total cholesterol, high-density lipoprotein-cholesterol, blood pressure, and diabetes, has been found to be associated with cognitive health, but these findings have not been validated in a representative sample in the United States. We aimed to examine the associations of Framingham risk score with cognitive function among older adults in a nationally representative sample, as well as by race or ethnicity, education, and family income.

METHODS AND RESULTS: A total of 2254 older adults ≥60years (57% female, 79% non-Hispanic White) in the National Health and Nutrition …

Patterns Of Hiv Disclosure And Its Impact On The Hiv Care Continuum Among Black Men Who Have Sex With Men In South Carolina, Xueying Yang Ph.D., Titilayo A. James, Monique J. Brown Ph.D., Mph, Tony Brown, Sydney Zarsadias, Ran Zhang, Fanghui Shi, Xiaoming Li Ph.D.

Faculty Publications

Addressing the psychosocial concerns of Black men who have sex with men (MSM), such as HIV disclosure, is critical for effective HIV treatment efforts. Black MSM living with HIV experience multiple psychosocial challenges, such as “triple stigma” due to their sexual orientation, racial minority status, and HIV status, which hinder their HIV disclosure and subsequent HIV care-seeking behavior. Our study sought to examine the HIV disclosure patterns and their impact on the HIV care continuum among Black MSM using a qualitative approach. Semi-structured interviews were carried out among 28 Black MSM aged ≥18 years old living in South Carolina. A …

Trends In Resources For Neonatal Intensive Care At Delivery Hospitals For Infants Born Younger Than 30 Weeks' Gestation, 2009-2020, Nansi S. Boghossian, Marco Geraci, Ciaran S. Phibbs, Scott A. Lorch, Erika M. Edwards, Jeffrey D. Horbar

Faculty Publications

Importance: In an ideal regionalized system, all infants born very preterm would be delivered at a large tertiary hospital capable of providing all necessary care. Objective: To examine whether the distribution of extremely preterm births changed between 2009 and 2020 based on neonatal intensive care resources at the delivery hospital. Design, Setting, and Participants: This retrospective cohort study was conducted at 822 Vermont Oxford Network (VON) centers in the US between 2009 and 2020. Participants included infants born at 22 to 29 weeks' gestation, delivered at or transferred to centers participating in the VON. Data were analyzed from February to …

Survival Models With Background Mortality, Shujie Chen

Theses and Dissertations

In this dissertation, we focus on studying three mixture cure models with background mortality. With the development of treatment, patients may be cured and suffer from other cause of death. The cure model with background mortality can measure the population cure which refers to the patients with comparable mortality with their counterpart in general population. Three types of survival models are investigated, including generalized odds rate (GOR) model, cure model with background mortality for right censoring and interval censoring, and extended illness death model via incorporating “cure” fraction. All methods are validated via comprehensive simulation studies and real data application. …

Detecting Spatially Varying Coefficient Effects With Conditional Autoregressive Models: A Simulation Study Using Social Determinants Of Health Screening Data, Reid J. Demass

Theses and Dissertations

Generalized linear models which include spatially varying coefficient terms allow researchers to determine if the association between predictor and outcome variables vary across geographic space. Such models are particularly applicable to research with public health data where interventions and limited health care resources must be allocated carefully. The integrated nested Laplace approximation (INLA) methodology available in the R INLA package is a popular tool to estimate spatially varying coefficients. To assess the performance of the estimation procedure, patient emergency department (ED) visits were simulated from data sourced from a pilot study at Prisma Health. The INLA technique was used to …

Sparse Partitioned Empirical Bayes Ecm Algorithms For High-Dimensional Linear Mixed Effects And Heteroscedastic Regression, Anja Zgodic

Theses and Dissertations

Variable selection methods in both the frequentist and Bayesian frameworks are powerful techniques that provide prediction and inference in high-dimensional linear regression models. These methods often assume independence between observations and normally distributed errors with the same variance. In practice, these two assumptions are often violated. To mitigate this, we develop efficient and powerful Bayesian approaches for linear mixed modeling and heteroscedastic linear regression. These method offers increased flexibility through the development of empirical Bayes estimators for hyperparameters, with computationally efficient estimation through the Expectation Conditional-Minimization (ECM) algorithm. The novelty of these approaches lies in the partitioning and parameter expansion, …