Biostatistics Commons^™

On Cox Proportional Hazards Model Performance Under Different Sampling Schemes, Hani Samawi, Lili Yu, Jingjing Yin

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Cox’s proportional hazards model (PH) is an acceptable model for survival data analysis. This work investigates PH models’ performance under different efficient sampling schemes for analyzing time to event data (survival data). We will compare a modified Extreme, and Double Extreme Ranked Set Sampling (ERSS, and DERSS) schemes with a simple random sampling scheme. Observations are assumed to be selected based on an easy-to-evaluate baseline available variable associated with the survival time. Through intensive simulations, we show that these modified approaches (ERSS and DERSS) provide more powerful testing procedures and more efficient estimates of hazard ratio than those based on …

Employee Attrition: Analyzing Factors Influencing Job Satisfaction Of Ibm Data Scientists, Graham Nash

Symposium of Student Scholars

Employee attrition is a relevant issue that every business employer must consider when gauging the effectiveness of their employees. Whether or not an employee chooses to leave their job can come from a multitude of factors. As a result, employers need to develop methods in which they can measure attrition by calculating the several qualities of their employees. Factors like their age, years with the company, which department they work in, their level of education, their job role, and even their marital status are all considered by employers to assist in predicting employee attrition. This project will be analyzing a …

Statistical Analysis Of The Relationship Between Protected Bird Species And National Parks, Katherine Harmon

Symposium of Student Scholars

The ecological diversity of Earth is majorly threatened by habitat loss due to the destruction by human intervention. The conservation status of all identified species are classified into nine categories of varying vulnerability as described by the International Union for Conservation of Nature’s Red List. By understanding the vulnerability of specific species, scientists can work to maintain a viable and healthy ecosystem globally by instilling rules and regulations of observed habitats for threatened species. These habitats are identified by surveying potential locations for threatened species and determining the population size at each site. An example of one of these surveys …

A Pharmacoepidemiological Study Of Myocarditis And Pericarditis Following The First Dose Of Mrna Covid-19 Vaccine In Europe, Joana Tome, Logan Cowan, Isaac Fung

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

This study assessed the myocarditis and pericarditis reporting rate of the first dose of mRNA COVID-19 vaccines in Europe. Myocarditis and pericarditis data pertinent to mRNA COVID19 vaccines (1 January 2021–11 February 2022) from EudraVigilance database were combined with European Centre for Disease Prevention and Control (ECDC)’s vaccination tracker data. The reporting rate was expressed as events (occurring within 28 days of the first dose) per 1 million individuals vaccinated. An observed-to-expected (OE) analysis quantified excess risk for myocarditis or pericarditis following the first mRNA COVID-19 vaccination. The reporting rate of myocarditis per 1 million individuals vaccinated was 17.27 (95% …

Knowledge, Attitude, And Behavioral Intention About Oral Cancer Among Public Health Students In Southeast Georgia, Ravneet Kaur, Gulzar H. Shah

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Background: Oral cancer (OC) is a significant public health problem; however, the degree to which the future public health workforce is aware of this issue is not well researched. The purpose of this study is to explore the level of knowledge, attitudes, and behavioral intentions about OC among public health students.
Materials and Methods: A sequential exploratory mixed-method research design was employed for this study. Using quantitative and qualitative measures, a survey was administered to 129 public health students. Subsequently, to understand the quantitative findings, two follow-up focus groups were conducted with survey participants.
Results: We found …

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. …

Prevalence Of Sars-Cov-2 Antibodies In Liberty University Student Population, Emily Bonus

Senior Honors Theses

In 2020, the virus SARS-CoV-2 gained attention as it spread around the world. Its antibodies are poorly understood, and little research focuses on those with few COVID-19 complications yet large numbers of close contacts: university students. This longitudinal study recorded SARS-CoV-2 antibody presence in 107 undergraduate Liberty University students twice during early 2021. After extensive data cleaning and the application of various statistical tests and ANOVAs, the data seems to show that in the case of COVID-19 infections, SARS-CoV-2 IgM antibodies are immediately produced, and then IgG antibodies follow later. However, the COVID-19 vaccine causes the production of both IgM …

Community Participation And Perspectives Of Ambondrolava Mangrove Restoration Project, Nadine Shannon

Independent Study Project (ISP) Collection

Madagascar’s mangrove forests are intertidal ecosystems that provide numerous valuable ecosystem services but are nonetheless under pressure from large amounts of deforestation. On the southwestern coast of Madagascar, the village of Ambondrolava practices community led management of the mangrove and its resources. This research project studied the evolution of the mangrove area using GIS data, and investigated, through interviews, the relationship between the local community of Ambondrolava and the organizations that manage the mangrove ecosystem. From 2000 to 2018, the zone of the mangrove has experienced a net loss in area every year, despite reforestation efforts. Most community members interviewed …

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, …

Wernicke's Encephalopathy: Mapping The Risk Factors Throughout The State Of South Carolina, Shannon M. Rychener

Senior Theses

Wernicke’s Encephalopathy is a consistently underrecognized neurodegenerative brain disorder resulting from prolonged thiamine deficiency. Clinical presentation of the disease results from brain lesions attributable to thiamine deficiency. Because these lesions occur in various locations in the cerebral cortex, symptoms can vary significantly. Varied presentation of symptoms, in addition to the lack of a widely accepted biomarker for the disorder cause challenges to clinicians when identifying and diagnosing the disorder. Due to these challenges, healthcare providers must heavily rely on patient history and risk factor prevalence when multiple symptoms of the disorder are present. By mapping the prevalence of the four …

The Effects Of Demographics And Risk Factors On The Morphological Characteristics Of Human Femoropopliteal Arteries, Sayed Ahmadreza Razian, Majid Jadidi, Alexey Kamenskiy

UNO Student Research and Creative Activity Fair

Background: Disease of the lower extremity arteries (Peripheral Arterial Disease, PAD) is associated with high morbidity and mortality. During disease development, the arteries adapt by changing their diameter, wall thickness, and residual deformations, but the effects of demographics and risk factors on this process are not clear.

Methods: Superficial femoral arteries from 736 subjects (505 male, 231 female, 12 to 99 years old, average age 51±17.8 years) and the associated demographic and risk factor variables were used to construct machine learning (ML) regression models that predicted morphological characteristics (diameter, wall thickness, and longitudinal opening angle resulting from the …

Fuzzy Kc Clustering Imputation For Missing Not At Random Data, Markku A. Malmi Jr.

USF Tampa Graduate Theses and Dissertations

Research has a variety of difficulties, especially when involving human subjects, and one of the most prevalent is the issue of missing data. Missing data will always be present in research due to the fact there is no perfect method for collecting data and protecting against human error or mechanical failure. This requires researchers to be able to mitigate the problems that come along with missing data; reduction in power of an analysis and bias introduced by the missing pattern. This research investigated a non-parametric method using a nested approach of fuzzy K-Modes and fuzzy C-Means clustering to impute missing …

Patient And Physician Factors Associated With First Diagnosis Of Non-Affective Psychotic Disorder In Primary Care, Joshua C. Wiener, Rebecca Rodrigues, Jennifer N S Reid, Suzanne Archie, Richard G Booth, Chiachen Cheng, Saadia Hameed Jan, Paul Kurdyak, Arlene G Macdougall, Lena Palaniyappan, Bridget L Ryan, Kelly K. Anderson

Epidemiology and Biostatistics Publications

Primary care physicians play a central role in pathways to care for first-episode psychosis, and their increased involvement in early detection could improve service-related outcomes. The aim of this study was to estimate the proportion of psychosis first diagnosed in primary care, and identify associated patient and physician factors. We used linked health administrative data to construct a retrospective cohort of people aged 14-35 years with a first diagnosis of non-affective psychosis in Ontario, Canada between 2005-2015. We restricted the sample to patients with help-seeking contacts for mental health reasons in primary care in the six months prior to first …

Evaluating The Feasibility And Potential Impacts Of A Recovery-Oriented Psychosocial Rehabilitation Toolkit In A Health Care Setting In Kenya: A Mixed-Methods Study, Regina Casey, Joshua C. Wiener, Terry Krupa, Rosemary Lysaght, Marlene Janzen Le Ber, Ruth Ruhara, Elizabeth Price, Romaisa Pervez, Sean Kidd, Victoria Mutiso, David M Ndetei, Arlene G Macdougall

Epidemiology and Biostatistics Publications

OBJECTIVES: This pilot study evaluated the feasibility and potential impacts of delivering the Psychosocial Rehabilitation (PSR) Toolkit for people with serious mental illness within a health care setting in Kenya.

METHOD: This study used a convergent mixed-methods design. Participants were people with serious mental illness (n = 23), each with an accompanying family member, who were outpatients of a hospital or satellite clinic in semirural Kenya. The intervention consisted of 14 weekly group sessions of PSR cofacilitated by health care professionals and peers with mental illness. Quantitative data were collected from patients and family members using validated outcome measures before …

Presidential Vote Share And Covid-19 Vaccination Rate In Indonesia: A District-Level Cross-Sectional Ecological Study, Gede Benny Setia Wirawan, Ni Luh Zallila Gustina, Ivy Cerelia Valerie, I Gusti Ayu Indah Pradnyani Rs, Muchamad Zaenal Arifin, Pande Putu Januraga

Kesmas

Political affiliation has been reported as a determinant of COVID-19 vaccine acceptance in some countries, although few studies have examined the Asian context. This study aims to fill this gap by employing an ecological study design using Indonesian regions as data points. Political affiliation was represented by incumbent President Jokowi’s vote share in the 2019 presidential election. Potential confounders included population density, human development index, availability of hospitals and primary health care, 2019–2020 economic growth, COVID-19 mortality rate, and proportion of Muslims in the population. The final analysis included 201 out of 501 districts and cities in Indonesia. Controlling for …

Oxidative Stress Levels Of Fine Particulate Matter (Pm2.5) And Urinary Glutathione Of Microbus Drivers, Purnama Sidebang, Agustin Kusumayati, Budi Haryanto

Kesmas

Urinary glutathione levels are known to be an early indicator of oxidative stress in travelers. This study analyzed the association between particulate matter (PM2.5) exposure on the road and urine glutathione levels in Jakarta’s microbus drivers. This cross-sectional study involved 96 microbuses (one of Jakarta’s public transportations) drivers of nine routes in Kampung Melayu Bus Station, Jakarta, Indonesia. An anthropometric assessment and a structured questionnaire were employed. Along with the participants driving on the road, real-time personal equipment measuring PM2.5 exposure concentrations was used. Total glutathione levels were measured using a colorimetric method. A correlation test and linear regression analysis …

Information-Motivation-Behavioral Skill In Diabetes Self-Management Using Structural Equation Modeling Analysis, Dien Kurtanty, Adang Bachtiar, Cicilya Candi, Alya Pramesti, Almira Fanny Rahmasari

Kesmas

Diabetes is the “mother” of various diseases increasing the risk of morbidity and mortality. Diabetes self-management, an effort made by patients to control blood sugar levels, is an important part of the management strategy. Therefore, this study analyzed information, motivation, and behavioral skills associated with diabetes self-management. Data were collected in the Special Capital Region of Jakarta, with 277 diabetic patients selected using a questionnaire by a systematic random sampling method. The analyzed variables were information (with indicator variables of information on physical activity, nutritional intake, drug consumption, and blood sugar monitoring); sociodemographic (age, sex, occupation, education level, and duration …

Job Satisfaction Model Of Primary Health Care Midwives Based On Indonesian Workforce Research In The Health Sector, Mieska Despitasari, Adang Bachtiar, Harimat Hendarwan, Besral Besral, Yuyun Yuniar

Kesmas

Promotive, preventive, curative, and rehabilitative efforts that are comprehensive, integrated, and sustainable are employed to enhance the health state of the global population. Within this context, however, the quality of primary health care depends on job satisfaction, which leads to the happiness of human resources in the health sector. Therefore, this study aimed to analyze and formulate a job satisfaction model among primary health care midwives in Indonesia. This study was an advanced secondary data analysis of a cross-sectional study conducted in 2017 by the National Institute of Health Research and Development, Ministry of Health of the Republic of Indonesia. …

The Effect Of Covid-19-Related Occupational Stress And Burnout In Referral Hospital Nurses, Yulastri Arif, Masyithah Fadhani

Kesmas

Nurses' continuous contribution to patient health makes them prone to occupational stress, which has been exacerbated during the COVID-19 pandemic. Occupational stress that lasts for a long time and is not resolved may cause burnout. Burnout experienced by nurses can impact patients, hospital services, and themselves. This study aimed to determine the effect of occupational stress on the incidence of nurse burnout during the COVID-19 pandemic. It used a quantitative approach with a cross-sectional design. The study sample was 235 nurses in six COVID-19 referral hospitals in West Sumatra from a proportional random sampling technique. Data were collected using a …

Developing A New Tool For Early Detection Of The Nutritional And Health Risk Factors Of Urban Workers’ Productivity, Hildagardis Meliyani Erista Nai, Arimbi Karunia Estri, Christina Ririn Widianti

Kesmas

Nutrition and health play vital roles in work productivity. This study aimed to develop a risk self-assessment tool called Early Detection of the Nutritional and Health Risk Factors on the productivity of urban workers. This study was conducted in two stages: 1) the development of the tool to determine the nutritional and health risk factors that affect productivity based on literature reviews and scoring systems and 2) the testing of validity and reliability. Finally, the tool contained 63 items, including 28 items on nutritional risk factors and 35 on health risk factors. The validity of the tool was assessed using …

Obesity And Asthma Risk In Indonesian Adults: Findings From The 2018 Indonesia Basic Health Research, Hoirun Nisa

Kesmas

Obesity and asthma are both global public health challenges. Mounting evidence suggests that obesity may increase asthma risk in adults; however, the association by sex remains uncertain. This study examined the association of obesity with asthma risk in Indonesian adult men and women. Data were obtained from the 2018 Indonesia Basic Health Research. The analysis included 299,837 men and 333,218 women aged ≥18 years. Asthma was identified by the self-report of a doctor’s diagnosis. Obesity was defined as a body mass index ≥30 kg/m2. A logistic regression was used for data analysis. Asthma prevalence was 2.7% (2.5% in men and …

Maternal And Child Health Handbook Utilization, Quantity And Quality Of Antenatal Services, And Maternal Emergency Rates In Padang City In 2022, Rena Afri Ningsih, Yusrawati Yusrawati, Joserizal Serudji

Kesmas

This study analyzed the relationship between the utilization of the Indonesian Ministry of Health’s Maternal and Child Health Handbook and the quantity and quality of antenatal care to maternal emergency levels. This study applied mixed methods with a consecutive sampling technique and included 108 mothers undergoing maternal emergencies at a central general hospital (quantitative) and eight mothers, seven midwives, and five cadres at primary health cares (qualitative) as informants. The result showed a relationship between the utilization of the Maternal and Child Health Care Handbook (p-value = 0.043), the quantity of antenatal care (p-value

The Determinants Of Stunting In The Under-Five In Three Municipalities In The Special Capital Region Of Jakarta, Tria Astika Endah Permatasari, Chairunnisa Chairunnisa, Hernani Djarir, Lily Herlina, Munaya Fauziah, Andriyani Andriyani, Yudi Chadirin

Kesmas

The COVID-19 pandemic has impacted the global decline in public health status. This study aimed to analyze the determinants of stunting in the under-five in three municipalities in the Special Capital Region of Jakarta, Indonesia. A cross-sectional study was conducted in August-December 2020 with 460 pairs of mothers and children selected by simple random sampling. Stunting was measured using a conventional anthropometric index (length/height-for-age), and anthropometric failure was measured using the Composite Index of Anthropometric Failure. The prevalence of stunting, underweight, and wasting was 41.5%,35%, and 19.8%, respectively, and 62% of the under-five experienced anthropometric failure. The dominant factor associated …

Turnover, Covid-19, And Reasons For Leaving And Staying Within Governmental Public Health, Jonathan P. Leider, Gulzar H. Shah, Valerie A. Yeager, Jingjing Yin, Kusuma Madamala

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Background and Objectives:

Public health workforce recruitment and retention continue to challenge public health agencies. This study aims to describe the trends in intention to leave and retire and analyze factors associated with intentions to leave and intentions to stay.

Design:

Using national-level data from the 2017 and 2021 Public Health Workforce Interests and Needs Surveys, bivariate analyses of intent to leave were conducted using a Rao-Scott adjusted chi-square and multivariate analysis using logistic regression models.

Results:

In 2021, 20% of employees planned to retire and 30% were considering leaving. In contrast, 23% of employees planned to retire and 28% …

Probabilistic Methods For Inferring The Order Of Pathway Alterations During Carcinogenesis And Cancer Subtype Classification, Menghan Wang

Theses and Dissertations--Statistics

Carcinogenesis is a complex process involving somatic mutations in a number of key biological pathways. Studying cancer evolution is an important task which contributes to better understanding of cancer biology and facilitates identification of new therapeutic targets. We focus on two important questions in cancer evolution. The first question is to delineating the temporal order of pathway mutations during tumorigenesis. And the other question is to cluster patients into biologically meaningful cancer subtypes. We present new statistical methods to 1)leverage functional annotations of mutations to enhance estimation of the order of pathway mutations during carcinogenesis, 2) incorporate intra-tumoral heterogeneity information …

High Dimensional Data Analysis: Variable Screening And Inference, Lei Fang

Theses and Dissertations--Statistics

This dissertation focuses on the problem of high dimensional data analysis, which arises in many fields including genomics, finance, and social sciences. In such settings, the number of features or variables is much larger than the number of observations, posing significant challenges to traditional statistical methods.

To address these challenges, this dissertation proposes novel methods for variable screening and inference. The first part of the dissertation focuses on variable screening, which aims to identify a subset of important variables that are strongly associated with the response variable. Specifically, we propose a robust nonparametric screening method to effectively select the predictors …

Striving For Appropriate Antibiotic Use: A Biomarker Initiative, And Outcomes Associated With Azithromycin Exposure, Amanda Gusovsky

Theses and Dissertations--Pharmacy

The introduction of antibiotics into clinical practice is considered the greatest medical breakthrough of the 20^thcentury. However, the use of antibiotics can contribute to the development of resistance. In the United States (U.S.), approximately 2.8 million people are infected with antibiotic-resistant bacteria each year, and more than 35,000 people die as a result. Moreover, some antibiotics are known to cause cardiac side effects including QT prolongation, hypotension, and ventricular arrythmias. The U.S. Centers for Disease Control and Prevention (CDC) defines appropriate antibiotic use as the effort to use “the right antibiotic, at the right dose, for the right …

Potential Alzheimer's Disease Plasma Biomarkers, Taylor Estepp

Theses and Dissertations--Epidemiology and Biostatistics

In this series of studies, we examined the potential of a variety of blood-based plasma biomarkers for the identification of Alzheimer's disease (AD) progression and cognitive decline. With the end goal of studying these biomarkers via mixture modeling, we began with a literature review of the methodology. An examination of the biomarkers with demographics and other health factors found evidence of minimal risk of confounding along the causal pathway from biomarkers to cognitive performance. Further study examined the usefulness of linear combinations of biomarkers, achieved via partial least squares (PLS) analysis, as predictors of various cognitive assessment scores and clinical …

Economics Of Maple Syrup Production In Kentucky, Bobby Thapa

Theses and Dissertations--Forestry and Natural Resources

Maple syrup production is traditionally associated with New England regions in the United States, but there is growing interest in expanding it to other regions with suitable environmental conditions, including Kentucky. This study presents an in-depth analysis of the potential production and economic impacts of maple syrup in Kentucky using a multi-method approach. First, the study applies a stochastic production model to assess the effects of climatic and tree variables on maple syrup yield. The results reveal that several variables, including the number of maple trees, taps, temperatures, tapping season length, and time, significantly affect maple syrup yield. Second, input-output …