Biostatistics Commons^™

Dependent Censoring In Survival Analysis, Zhongcheng Lin

Dissertations

This dissertation mainly consists of two parts. In the first part, some properties of bivariate Archimedean Copulas formed by two time-to-event random variables are discussed under the setting of left censoring, where these two variables are subject to one left-censored independent variable respectively. Some distributional results for their joint cdf under different censoring patterns are presented. Those results are expected to be useful in both model fitting and checking procedures for Archimedean copula models with bivariate left-censored data. As an application of the theoretical results that are obtained, a moment estimator of the dependence parameter in Archimedean copula models is …

Genetic Contributors Of Incident Stroke In 10,700 African Americans With Hypertension: A Meta-Analysis From The Genetics Of Hypertension Associated Treatments And Reasons For Geographic And Racial Differences In Stroke Studies, Nicole D. Armstrong, Vinodh Srinivasasainagendra, Amit Patki, Rikki M. Tanner, Bertha A. Hidalgo, Hemant K. Tiwari, Nita A. Limdi, Ethan M. Lange, Leslie A. Lange, Donna K. Arnett, Marguerite R. Irvin

Epidemiology and Environmental Health Faculty Publications

Background: African Americans (AAs) suffer a higher stroke burden due to hypertension. Identifying genetic contributors to stroke among AAs with hypertension is critical to understanding the genetic basis of the disease, as well as detecting at-risk individuals.

Methods: In a population comprising over 10,700 AAs treated for hypertension from the Genetics of Hypertension Associated Treatments (GenHAT) and Reasons for Geographic and Racial Differences in Stroke (REGARDS) studies, we performed an inverse variance-weighted meta-analysis of incident stroke. Additionally, we tested the predictive accuracy of a polygenic risk score (PRS) derived from a European ancestral population in both GenHAT and REGARDS AAs …

Dysregulation Of Dna Methylation And Epigenetic Clocks In Prostate Cancer Among Puerto Rican Men, Anders Berglund, Jaime Matta, Jarline Encarnación-Medina, Carmen Ortiz-Sanchéz, Julie Dutil, Raymond Linares, Joshua Marcial, Caren Abreu-Takemura, Natasha Moreno, Ryan Putney, Ratna Chakrabarti, Hui Yi Lin, Kosj Yamoah, Carlos Diaz Osterman, Liang Wang, Jasreman Dhillon, Youngchul Kim, Seung Joon Kim, Gilberto Ruiz-Deya, Jong Y. Park

School of Public Health Faculty Publications

In 2021, approximately 248,530 new prostate cancer (PCa) cases are estimated in the United States. Hispanic/Latinos (H/L) are the second largest racial/ethnic group in the US. The objective of this study was to assess DNA methylation patterns between aggressive and indolent PCa along with ancestry proportions in 49 H/L men from Puerto Rico (PR). Prostate tumors were classified as aggressive (n = 17) and indolent (n = 32) based on the Gleason score. Genomic DNA samples were extracted by macro-dissection. DNA methylation patterns were assessed using the Illumina EPIC DNA methylation platform. We used ADMIXTURE to estimate global ancestry proportions. …

Acute Pediatric Chagas Disease In Antioquia, Colombia: A Geographic Location Of Suspected Oral Transmission, Lídia Gual-Gonzalez, Catalina Aango-Ferreira, Laura Camila Lopera-Restrepo, Omar Cantillo-Barraza, Daniela Velásquez Marín, Natalia Restrepo Bustamante, Omar Triana-Chavez, Melissa Nolan Ph.D., Mph

Faculty Publications

Chagas disease, Trypanosoma cruzi infection, is an insidious cause of heart failure in Latin America. Early diagnosis and treatment are critical to prevent irreversible myocardial damage that progressively accumulates over decades. Several structural barriers account for the less than 1% of cases in Colombia being treated, including poor physician knowledge, especially considering that some regions are considered non-endemic. The two cases reported here represent an emerging epidemiologic scenario associated with pediatric Chagas disease. Both cases are suspected oral transmitted parasitic infection in a geographic region of Colombia (Andean region of Antioquia) where no previous oral transmission of Chagas disease had …

Approximate Likelihood Based Estimations For Joint Models With Intractable Likelihoods, Karl Stessy M. Bisselou

Theses & Dissertations

This dissertation focuses on the development of approximation approaches for the joint modeling (JM) of repeated measures data and time-to-event data in the presence of analytically or numerically intractable likelihoods. Current likelihood-based inferences for JMs show several limitations including (i) intractability of integrals during marginal likelihood derivations due to the complexity in computations, and (ii) the large number of nuisance parameters (unobserved) posing a problem with convergence. The h-likelihood (HL) and synthetic likelihood (SL) are two computationally efficient estimation approaches that overcome these challenges.

In the presence of extremely high censoring rates, the HL can produce bias parameter estimates. We …

Smoking, Alcohol Consumption, And Depression In Association With Incidence Of Type 2 Diabetes Among Mexican Americans In Starr County, Texas, Gabriela Rubannelsonkumar

Honors Program Theses and Research Projects

Previous studies on conditions like obesity, hypertension, and type 2 diabetes mellitus (T2DM) have explored the correlations between them and various other human conditions, including aortic stiffness, left ventricular hypertrophy and sleep apnea, as they predict possibilities of developing certain diseases in Mexican Americans. This study aims to observe the correlation between lifestyle decisions that could relate to the onset of the depression in normal, prediabetic, and diabetic individuals. These include smoking habits and alcohol consumption. Many papers have previously conducted research on these lifestyle habits as they relate to obesity, hypertension, diabetes, however, have done so in a singular …

The Efficacy Of Plant-Based Dietary Program In Patients With Diabetes: A Pilot Study, Reuben Adatorwovor, Nisha Sharma, Dakota Mccoy, Sharon Wasserstrom, Matthew Robinson, Jacquelyn Nyenhuis, Sowmya Suryanarayanan

Biostatistics Faculty Publications

Dietary choices play a key role in insulin sensitivity among diabetes patients. An 8-week pilot study was conducted to evaluate whether a mostly plant-based dietary program will lead to improvement in biochemical markers in adults with diabetes. The dietary program included educational presentations, weekly cooking demonstrations and small group discussions. A sample of thirty-two adults with diabetes (types 1 and 2) were recruited and seventeen (53%) completed the study. Matched-pair tests and Fishers exact tests were used to compare the changes in means and proportion of the participants’ responses. There were changes in HbA1c, lipids, CRP (mg/L), cholesterol (mg/dL), HDL …

Basis For Changes In The Disease Burden Estimates Related To Vitamin A And Zinc Deficiencies In The 2017 And 2019 Global Burden Of Disease Studies, Sonja Y. Hess, Alexander C. Mclain, Haley Lescinsky, Kenneth H. Brown, Ashkan Afshin, Reed Atkin, Saskia Jm Osendarp

Faculty Publications

Background:

The Global Burden of Disease (GBD) Study provides estimates of death and disability from eighty-seven risk factors, including some micronutrient deficiencies. Objectives:

To review methodological changes that led to large differences in the disease burden estimates for vitamin A and Zn deficiencies between the GBD 2017 and 2019 Studies. Methods:

GBD publications were reviewed; additional information was provided by GBD researchers. Results:

Vitamin A deficiency prevalence is based on plasma retinol concentration, whereas the estimate for Zn deficiency prevalence uses dietary adequacy as a proxy. The estimated global prevalence of vitamin A deficiency for children aged 1–4 years in …

Nutrient Intake And Dietary Inflammatory Potential In Current And Recovered Anorexia Nervosa, Olivia Patsalos, Bethan Dalton, Christia Kyprianou, Joseph Firth, Nitin Shivappa Mbbs, Mph, Ph.D., James Hébert Scd, Ulrike Schmidt, Hubertus Himmerich

Faculty Publications

Anorexia nervosa (AN) is characterised by disrupted and restrictive eating patterns. Recent investigations and meta-analyses have found altered concentrations of inflammatory markers in people with current AN. We aimed to assess nutrient intake in participants with current or recovered AN, as compared to healthy individuals, and explore group differences in dietary inflammatory potential as a possible explanation for the observed alterations in inflammatory markers. We recruited participants with current AN (n = 51), those recovered from AN (n = 23), and healthy controls (n = 49). We used the Food Frequency Questionnaire (FFQ), to calculate a Dietary …

Confidence Interval For The Mean Of A Beta Distribution, Sean Rangel

Electronic Theses and Dissertations

Statistical inference for the mean of a beta distribution has become increasingly popular in various fields of academic research. In this study, we developed a novel statistical model from likelihood-based techniques to evaluate various confidence interval techniques for the mean of a beta distribution. Simulation studies will be implemented to compare the performance of the confidence intervals. In addition to the development and study involving confidence intervals, we will also apply the confidence intervals to real biological data that was gathered by the Department of Biology at Stephen F. Austin State University and provide recommendations on the best practice.

Data-Driven Statin Initiation Evaluation And Optimization For Prediabetes Population, Muhenned A. Abdulsahib

Graduate Theses and Dissertations

This dissertation develops quantitative models to support medical decision making of statininitiation considering the uncertainty in disease progression for prediabetes patients. A mathematical model is built to help medical decision-makers take action of statin initiation under uncertainty in future prediabetes progressions. The association between cholesterol drug use, such as statin, and elevating glucose level attracted considerable amounts of attention in the literature. Statin effects on glucose vary with respect to different levels of glucose. The first chapter of this dissertation introduces the problem and an overview of the tools that will be used to solve it. In the second chapter …

Estimating Treatment Effect On Medical Cost And Examining Medical Cost Trajectory Using Splines And Change Point Techniques., Indranil Ghosh

Electronic Theses and Dissertations

In the world of growing medical needs, other than the clinical outcomes, the cost of healthcare is one of the important aspects to evaluate. The cost of treatment could act as a decisive factor on which one to choose from two equally likely effective treatment options. In literature, the most used quantity for the cost of treatment is cumulative lifetime cost since the diagnosis of a disease. While it provides a bird' eye view of the treatment cost, it fails to capture the underlying pattern of the treatment cost trajectory. We developed a marginal structural functional model (MSFM) using an …

Comparing Machine Learning Techniques With State-Of-The-Art Parametric Prediction Models For Predicting Soybean Traits, Susweta Ray

Department of Statistics: Dissertations, Theses, and Student Research

Soybean is a significant source of protein and oil, and also widely used as animal feed. Thus, developing lines that are superior in terms of yield, protein and oil content is important to feed the ever-growing population. As opposed to the high-cost phenotyping, genotyping is both cost and time efficient for breeders while evaluating new lines in different environments (location-year combinations) can be costly. Several Genomic prediction (GP) methods have been developed to use the marker and environment data effectively to predict the yield or other relevant phenotypic traits of crops. Our study compares a conventional GP method (GBLUP), a …

Challenges For Estimating The Global Prevalence Of Micronutrient Deficiencies And Related Disease Burden: A Case Study Of The Global Burden Of Disease Study, Sonja Y. Hess, Alexander C. Mclain Ph.D., Edward A. Frongillo Jr. Ph.D., Ashkan Afshin, Nicholas J. Kassebaum, Saskia Jm Osendarp, Reed Atkin, Rahul Rawat, Kenneth H. Brown

Faculty Publications

Information on the prevalence of micronutrient deficiencies is needed to determine related disease burden; underpin evidence-based advocacy; and design, deliver, and monitor safe, effective interventions. Assessing the global prevalence of deficiency requires a valid micronutrient status biomarker with an appropriate cutoff to define deficiency and relevant data from representative surveys across multiple locations and years. The Global Burden of Disease Study includes prevalence estimates for iodine, iron, zinc, and vitamin A deficiencies, for which recommended biomarkers and appropriate deficiency cutoffs exist. Because representative survey data are lacking, only retinol concentration is used to model vitamin A deficiency, and proxy indicators …

Predictors Of Poor Glycemic Control In Diabetic Clients With Mental Health Illness, Community Alliance, Omaha, Nebraska, Rachelle Flick

Capstone Experience: Master of Public Health

People with severe mental illness tend to die 10-25 years earlier than the general population (WHO). Main contributors to these premature deaths include comorbidities such as hypertension, cardiovascular disease, and diabetes. Diabetes prevalence in mentally ill people is 2 times higher than the general population (WHO). The World Health Organization is taking action to improve the health of people with severe mental illness. These efforts include creating protocols of prevention, identification, assessment, and treatment for mentally ill people, as well as improving access to general health services through the integration of physical and mental health services. Community Alliance, located in …

Effect Of Renin-Angiotensin System Inhibitors On Acute Kidney Injury Among Patients Undergoing Cardiac Surgery: A Review And Meta-Analysis, Han Zhou, Jingui Xie, Zhichao Zheng, Oon Cheong Ooi, Haidong Luo

Research Collection Lee Kong Chian School Of Business

Acute kidney injury (AKI) is a frequent complication of cardiac surgery, which can lead to higher mortality and long-term renal function impairment. The effect of perioperative renin-angiotensin system inhibitors (RASi) therapy on AKI incidence in patients undergoing cardiac surgery remains controversial. We reviewed related studies in PubMed, Scopus, and Cochrane Library from inception to February 2020. Two randomized controlled trials and 21 cohort studies were included in the meta-analysis, involving 76,321 participants. The pooled odds ratio and 95% confidence interval were calculated using the DerSimonian and Laird random-effects model. The results showed no significant association between perioperative RASi therapy and …

A Copula Model Approach To Identify The Differential Gene Expression, Prasansha Liyanaarachchi

Mathematics & Statistics Theses & Dissertations

Deoxyribonucleic acid, more commonly known as DNA, is a complex double helix-shaped molecule present in all living organisms and hosts thousands of genes. However, only a few genes exhibit differential expression and play a vital role in a particular disease such as breast cancer. Microarray technology is one of the modern technologies developed to study these gene expressions. There are two major microarray technologies available for expression analysis: Spotted cDNA array and oligonucleotide array. The focus of our research is the statistical analysis of data that arises from the spotted cDNA microarray. Numerous models have been proposed in the literature …

Statistical Analysis Based On Adaptive Progressive Hybrid Censored Data From Lomax Distribution, Amal Helu, Hani Samawi

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

In this article, we consider statistical inferences about the unknown parameters of the Lomax distribution basedon the Adaptive Type-II Progressive Hybrid censoring scheme, this scheme can save both the total test time and the cost induced by the failure of the units and increases the efficiency of statistical analysis. The estimation of the parameters is derived using the maximum likelihood (MLE) and the Bayesian procedures. The Bayesian estimators are obtained based on the symmetric and asymmetric loss functions. There are no explicit forms for the Bayesian estimators, therefore, we propose Lindley’s approximation method to compute the Bayesian estimators. A comparison …

Are We Passing On Violence To The Next Generation?: Gender Norms And Gender-Based Violence Attitudes Among Early Adolescents In Indonesia, I Gusti A A. Mahendra, Anggriyani Wahyu Pinandari, Ifta Choiriyah, Siswanto Agus Wilopo

Kesmas

Intensification of gender norms during puberty affects adolescents’ perceptions and behavior related to violence. This study examined the association between gender norms and gender-based violence (GBV) among early adolescents considering socio-ecological variables using cross-sectional data from 3,618 Indonesian Global Early Adolescent Study pupils. Chi square tests with simple and multiple logistic regression analyses examined how different factors' levels predict GBV. Among boys, GBV attitudes were found high (53%). Furthermore, they also had high heteronormative expectations, threatened feelings, experiences of violence, porn access, and 5+ adverse childhood experiences (ACEs). Logistic regression results revealed that adolescent boys having one or two scores …

A Healthy Dietary Pattern With A Low Inflammatory Potential Reduces The Risk Of Gestational Diabetes Mellitus, Lotta Pajunen, Liisa Korkalo, Noora Houttu, Outi Pellonperä, Kati Mokkala, Nitin Shivappa Mbbs, Mph, Ph.D., James Hébert Scd, Tero Vahlberg, Kristina Tertti, Kirsi Laitinen

Faculty Publications

Purpose An optimal diet for lowering the risk of gestational diabetes mellitus (GDM) is still to be defined, but may comprise of nutrient intakes, dietary patterns, diet quality, and eating frequency. This study was designed to investigate the contribution of diet in developing GDM in a comprehensive way. Methods The dietary intake of overweight or obese women, a risk group for GDM (n = 351), was assessed using 3-day food diaries and diet quality questionnaires in early pregnancy. Eating frequency and nutrient intakes were calculated, and dietary patterns identified using principal component analysis. The inflammatory potential of the diet was …

The Indonesian Strategy To Achieve Universal Health Coverage Through National Health Insurance System: Challenges In Human Resources, Atikah Adyas

Kesmas

Many countries are currently trying to achieve universal health insurance coverage in order to provide health protection for their population. Indonesia has received a strong political commitment to implement national health insurance including government support to finance the poor. The implementation of comprehensive national health insurance requires human resources, each of which has a role in fighting for noble goals for the welfare of all people. This paper is taken from the experience of Indonesia and several other countries as well as guidelines that can be used in exploring the role of human resources for the success of the implementation …

Mental Fatigue And Its Associated Factors Among Coal Mining Workers After One Year Of The Covid-19 Pandemic In Indonesia, Hendra Djamalus, Budi Utomo, I Made Djaja, Sjahrul M. Nasri

Kesmas

Mental fatigue among coal mining operators was related to driving activities that require high concentration. This study aimed to determine factors that contributed to mental fatigue among coal mine operators in Indonesia, specifically in Kalimantan and Sumatra, after a one-year COVID-19 pandemic. This cross-sectional study was conducted among 480 operators from two companies and seven sites. A self-administrated questionnaire in the Google Form was used to measure mental fatigue, the non-work-related factors (age, education, marital status, residence, and stress level), and work-related factors (working periods, shift pattern, type of shift, and work area in mining). The data analyzed using Chi-square …

The Covid-19 Pandemic: Role Of Coping Humor And Internal Health Locus Of Control On Social Dysfunction And Anxiety & Depression, Muhammad Arief Sumantri, Zahrani Zahrani, Hilda Rosa Ainiyah, Azmul Fuady Idham

Kesmas

The concerns about the impact of social distancing on mental health have been widely discussed. This study aimed to know the predictive effect of coping humor and Internal Health Locus of Control (Internal HLoC) on social dysfunction and anxiety & depression during the implementation of the COVID-19 social distancing agenda. This study was also intended to assess the effect of humor content on coping humor. A quantitative approach was used as the method ofthe study with 243 online-recruited participants, and a PLS-SEM analysis was applied to find out the predictive effect in this study. The results and conclusions showed that …

Breastfeeding Knowledge And Behavior In Lactational Amenorrhea Method (Lam) As A Natural Contraceptive, Mufdlilah Mufdlilah, Reza Bintangdari Johan, Sri Ratna Ningsih

Kesmas

The lactational amenorrhea method (LAM) is a natural contraceptive that is highly effective after the three essential criteria are fulfilled. However, there is a significantly low adoption resulting from poor knowledge and correct practices. This study aimed to determine the correlation between knowledge and behavior of breastfeeding mothers on breastfeeding as a natural contraceptive. This was an analytic observational study with a cross-sectional design involving 89 breastfeeding mothers and was performed from January to March 2018. Furthermore, data were collected using a questionnaire, and the results showed knowledge of breastfeeding mothers to be good (59.6%) and not good (51.7%). However, …

Integrated Model Of A Family Approach And Local Support In Tuberculosis Case Finding Efforts In People With Hiv/Aids, Erni Astutik, Chatarina Umbul Wahyuni, Imelda F E Manurung, Geofrey Ssekalembe

Kesmas

The human immunodeficiency virus (HIV) remains a major global public health problem. People with HIV/acquired immune deficiency syndrome (AIDS) are more susceptible to opportunistic infections such as tuberculosis (TB). Therefore, families and community leaders need to help monitor people living with HIV/AIDS (PLWHA). This study aimed to analyze an integrated family approach and local support model to detect TB cases in PLWHA. This study used a case-control study in Kupang City, East Nusa Tenggara Province, in July 2020. The sample comprised 100 people (50 PLWHA with TB case and 50 controls) using total sampling and random sampling, respectively. The variables …

Predictors Of The Covid-19 Social Distancing Practice Among Undergraduate Health Students In Samarinda City, Indonesia: A Cross-Sectional Study, Siti Hadijah Aspan, Pramon Viwattanakulvanid

Kesmas

Social distancing is a health protocol recommended by the World Health Organization (WHO) for reducing the spread of COVID-19. Undergraduate health students play an important role in the dissemination of accurate information. This study identified predictors that influenced the COVID-19 social distancing practice and examined the sources of social distancing information among undergraduate health students in Samarinda City, Indonesia. This cross-sectionalonline survey study (March-April 2021) involved 422 undergraduate students from medicine, public health, and pharmacy faculties at Mulawarman University. Binary logistic regression was conducted to identify factors associated with the COVID-19 social distancing practice. The results showed that age (AOR …

Knowledge, Attitudes, And Practices Of Health Personnel In Responding To The Covid-19 Pandemic In Indonesia, Dyah Suryani, Suyitno Suyitno, Maretalinia Maretalinia, Elvi Juliansyah, Vernonia Yora Saki, Kraichat Tantrakarnapa

Kesmas

The COVID-19 pandemic, originated in China, has spread to worldwide, including Indonesia. Until July 2021, the growth rate has been gradually increasing, and cases have been found in all 34 provinces of Indonesia. This cross-sectional study aimed to investigate the knowledge, attitude, and practices (KAP) of health personnel in the primary health care towards the COVID-19 pandemic in Indonesia using online self-report questionnaire. A total of 440 respondents contributed to this online survey. The average level of KAP were 7.7 out of 10.0, 14.3 out of 15.0, and 31.9 out of 36.0, respectively. There was no significant association between respondents’ …

The Seroprevalence Of Toxoplasma Gondii In Cats At The House Of Maternal Women With Toxoplasmosis In Badung, Indonesia, Made Subrata, Nyoman Mantik Astawa, Nyoman Tigeh Suryadi, Sang Gede Purnama, Kadek Karang Agustina, Ngakan Putu Anom Harjana, Made Damriyasa

Kesmas

Toxoplasmosis is a zoonotic disease caused by infection with the parasite called Toxoplasma gondii (T. gondii). The health and social impacts of the infectionare enormous, including miscarriage, hydrocephalus, blindness, and mental retardation. The occurrence of toxoplasmosis in maternal women cannot be se parated from cats around their houses. This study aimed to determine the seroprevalence of the parasite in cats found in the human carriers residences and identify the risk factors of toxoplasmosis in maternal women in Badung District, Bali Province, Indonesia. A total of 80 cat serum samples were obtained from two residential groups, 40 from the housing where …

How Risky People Of Getting Covid-19 Based On Their Daily Activities?, Fajar Ariyanti, Mustakim Mustakim, Moch T A Al Ayubi, Desty Pratiwi Marlisman

Kesmas

In Indonesia at the end of 2020, COVID-19 cases were increasing and predicted to continue, as it had not yet passed the peak of the pandemic curve. The government had implemented mobility restrictions to reduce exposure to COVID-19. This study aimed to identify the risk of people getting COVID-19 based on their daily activities. Using a cross-sectional design, this study took 315 respondents under non-probability sampling from September to October 2020. Thedata were analyzed using the Chi-square test with α 0.05. This study showed that the risk percentage of people infected with COVID-19 based on their daily activities was 15.56% …

Performance Of A Validated Spontaneous Preterm Delivery Predictor In South Asian And Sub-Saharan African Women: A Nested Case Control Study, Rasheda Khanam, Tracy C. Fleischer, Nansi Boghossian, Imran Nisar, Usha Dhingra, Sayedur Rahman, Angela C. Fox, Muhammad Iiyas, Arup Dutta, Nurun Naher, Ashoka D. Polpitiya, Usma Mehmood, Saikat Deb, Aziz Ahmed Choudhury, Md Bahadur Badsha, Karim Muhammad, Said Mohammed Ali, Salahuddin Ahmed, Durlin E. Hickok, Najeeha Iqbal, Et. Al.

Faculty Publications

Objectives

To address the disproportionate burden of preterm birth (PTB) in low- and middle-income countries, this study aimed to (1) verify the performance of the United States-validated spontaneous PTB (sPTB) predictor, comprised of the IBP4/SHBG protein ratio, in subjects from Bangladesh, Pakistan and Tanzania enrolled in the Alliance for Maternal and Newborn Health Improvement (AMANHI) biorepository study, and (2) discover biomarkers that improve performance of IBP4/SHBG in the AMANHI cohort.

Study design

The performance of the IBP4/SHBG biomarker was first evaluated in a nested case control validation study, then utilized in a follow-on discovery study performed on the same samples. …