Browsing Biostatistics by Title
Now showing items 144-163 of 215
-
On Estimation of Time-varying Population Attributable Fractions for Population-based Case-control Studies
The population attributable fraction (PAF) is an important measure in evaluating the contribution of risk factors to disease burden or mortality. It is a useful tool for planning of prevention actions. Recent development ... -
Parameter Selection of Sparse Functional Principal Component Analysis with fMRI data
With the advent of high throughput biotechnologies, it is increasingly common for the number of features measured on each subject to vastly exceed the number of subjects in modern biomedical studies. In this manuscript we ... -
Penalized discriminant analysis for multivariate functional data
We introduce a penalized discriminant analysis method for multivariate functional data supported on compact 1D domains, motivated by an application that aims to identify subjects with poor cognitive status from diffusion ... -
Performance of the NCI method of dietary intakes in small sample sizes
Modeling the population distribution of usual intake of episodically-consumed foods, primarily using 24-hour recall, is a challenging problem. The NCI method is the most recent major step in the evolution of specialized ... -
Population Genetic Inference with Identity by Descent
Identical-by-descent (IBD) segments carry important information on genetic relatedness between individuals and therefore are used widely for statistical inference in population genetics. In this work, we focus on the ... -
Power consideration and caveats of Causal Inference Test (CIT) for mediation analysis
Causal Inference Test (CIT) has been proposed to infer the causality mediation from a genotype to a trait through a candidate mediator, for example certain gene expression. This thesis aims to study the performance of CIT ... -
Practical Considerations for Modern Clinical Trials: Three Projects in Clinical Trial Design, Conduct and Analysis
This dissertation comprises three projects that span the design, conduct and analysis of contemporary clinical trials, presented in individual chapters. The first project extends methods for stratified randomization to ... -
Prediction of CYP3A4 metabolic activity from whole genome RNA-seq data with feature selection machine learning methods
CYP3A4, one of the isozyme of the cytochromes P450 (CYPs), contributes significantly to drug clearance and drug-drug interactions. The goals of this project are to identify hepatically-expressed genes that are associated ... -
Problems in Pedigrees and Phylogenies
(2013-07-23)The footprint of genetic inheritance can be observed among both familial relationships between individuals and evolutionary relationships between species. The former can be depicted by a pedigree, whereas the latter can ... -
Rare variant method for identity-by-descent detection in sequence data, and the time to most recent common ancestor given identity-by-descent segment length
(2013-11-14)Identity-by-descent (IBD) is defined as two individuals sharing a haplotype they have both inherited from a common ancestor, where a haplotype is a segment of genetic material found on a single homologue. Existing methods ... -
Recovering Natural History: Modeling Cardiovascular Biomarkers in the Presence of Endogenous Medication Use
In the modern era, cardiovascular biomarkers are often measured in the presence of medication use, whereby the observed value is different than the underlying untreated value for participants on medication. However, for ... -
Recurrent Episode Analyses of Pulmonary Exacerbations in the Infant Study of Inhaled Saline (ISIS) Trial
(2014-02-24)The Infant Study of Inhaled Saline (ISIS) randomized, controlled clinical trial evaluated the use of daily inhaled hypertonic saline treatment for 48 weeks to reduce the rate of pulmonary exacerbations in children of less ... -
Reframing Cox Proportional Hazards Model for Big Data and Neural Networks
In many medical and biomedical applications, we measure the outcome as a “time-to-event” (e.g., disease progression or death). The aim of this dissertation is to propose frameworks for survival analysis and prediction with ... -
Relationship of nighttime arousals and nocturnal cortisol in IBS and normal subjects
(2013-04-17)This study was a secondary analysis of data from a study investigating the association between inflammatory bowel syndrome (IBS) and nocturnal cortisol and catecholamines in a sample of IBS subjects and healthy controls. ... -
Risk factors analysis of longitudinal viral dynamics and immunological responses among HIV-discordant couples
In their 2011 paper “Prevention of HIV-1 infection with Early Antiretroviral Therapy” (Cohen, et al, New England Journal of Medicine, 2011), an interim analysis was performed for the HPTN 052 Study to address both personal ... -
Risk Prediction In Cardiovascular Epidemiology: Considerations for Modeling Composite Endpoints
This thesis reviews construction and evaluation of risk prediction scores in the context of cardiovascular disease. We give an overview of the clinical guidelines that make use of cardiovascular disease risk scores as well ... -
Sampling designs for resource efficient collection of outcome labels for machine-learning, with application to electronic medical records
In leveraging data from large-scale electronic medical record systems for research, an important step is the accurate identification of key clinical outcomes. Some outcomes must be derived or predicted from both structured ... -
Scaled matrix completion and cell deconvolution with NanoString data
This thesis explores two research problems in Chapters 1 and 2. Chapter 1 combines pivotal penalized estimation, with matrix completion, to introduce a new matrix completion problem, where the optimal tuning parameter does ... -
Searching for Predictive Subgroups
Our increased understanding of genomics and related fields has led to: 1) the identification of subtypes of cancer based on various biomarkers and 2) the development of drugs to target specific subtypes. We then use clinical ... -
Searching for Predictive Subgroups with Enhanced Treatment Effect in Clinical Trials using SHAPES
The complexity of the human genome and variability of individual health histories, living environments, and lifestyles have motivated the development of precision medicine with the goal to enable health care providers to ...