Biostatistics Commons^™

Effects Of Mantra Meditation Versus Music Listening On Knee Pain, Function, And Related Outcomes In Older Adults With Knee Osteoarthritis: An Exploratory Randomized Clinical Trial (Rct), Kim Innes, Terry Kit Selfe, Sahiti Kandati, Sijin Wen, Zenzi Huysmans

Faculty & Staff Scholarship

Objective. Disease-modifying treatments for OA remain elusive, and commonly used medications can have serious side effects. Although meditation and music listening (ML) have been shown to improve outcomes in certain chronic pain populations, research in OA is sparse. In this pilot RCT, we explore the effects of two mind-body practices, mantra meditation (MM) and ML, on knee pain, function, and related outcomes in adults with knee OA. Methods. Twenty-two older ambulatory adults diagnosed with knee OA were randomized to a MM (N=11) or ML program (N=11) and asked to practice 15-20 minutes, twice daily for 8 weeks. Core outcomes included …

Perfluoroalkyl Substances And Kidney Function In Chronic Kidney Disease, Anemia, And Diabetes, Baqiyyah N. Conway, Ashley N. Badders, Tina Costacou, John M. Arthur, Kim E. Innes

Faculty & Staff Scholarship

Background: Anemia often complicates chronic kidney disease (CKD), leading to insufficient tissue oxygenation and hypoxic injury, the factor thought to underlie progression from CKD to renal failure. Perfluorocarbons are potent oxygen transporters used in organ preservation and synthetic blood development. Data are scarce on their relationship with kidney function, especially in diabetes where anemia and hypoxia are more prevalent. We investigated the relationship of perfluoroalkyl acids (PFAS) with kidney function and variation by diabetes and anemia status.

Methods: Data on 53,650 adults (5,210 with diabetes) were obtained from the C8 Health Project. CKD was defined as an estimated glomerular filtration …

Discerning Suicide In Drug Intoxication Deaths: Paucity And Primacy Of Suicide Notes And Psychiatric History, Ian Rh Rockett, Eric D. Caine, Hilary S. Connery, Gail D'Onofrio, David J. Gunnell, Ted R. Miller, Kurt B. Nolte, Mark S. Kaplan, Nestor D. Kapusta, Christa L. Lilly, Lewis S. Nelson, Sandra L. Putnam, Steven Stack, Peeter Varnik, Lynne R. Webster, Haomiao Jia

Faculty & Staff Scholarship

Objective

A paucity of corroborative psychological and psychiatric evidence may be inhibiting detec- tion of drug intoxication suicides in the United States. We evaluated the relative importance of suicide notes and psychiatric history in the classification of suicide by drug intoxication versus firearm (gunshot wound) plus hanging/suffocation—the other two major, but overtly violent methods.

Methods

This observational multilevel (individual/county), multivariable study employed a general- ized linear mixed model (GLMM) to analyze pooled suicides and undetermined intent deaths, as possible suicides, among the population aged 15 years and older in the 17 states participating in the National Violent Death Reporting System …

Novel Caries Loci In Children And Adults Implicated By Genome-Wide Analysis Of Families, Manika Govil, Nandita Mukhopadhyay, Daniel E. Weeks, Eleanor Feingold, John R. Shaffer, Steven M. Levy, Alexandre R. Vieira, Rebecca L. Slayton, Daniel W. Mcneil, Robert J. Weyant, Richard J. Crout, Mary L. Marazita

Faculty & Staff Scholarship

Background: Dental caries is a common chronic disease among children and adults alike, posing a substantial health burden. Caries is affected by multiple genetic and environmental factors, and prior studies have found that a substantial proportion of caries susceptibility is genetically inherited.

Methods: To identify such genetic factors, we conducted a genome-wide linkage scan in 464 extended families with 2616 individuals from Iowa, Pennsylvania and West Virginia for three dental caries phenotypes: (1) PRIM: dichotomized as zero versus one or more affected primary teeth, (2) QTOT1: age-adjusted quantitative caries measure for both primary and permanent dentitions including pre-cavitated lesions, and …

Systematic Review And Meta-Analysis: Tuberculosis, Tnfα Inhibitors, And Crohn's Disease, Brent L. Cao

Honors Undergraduate Theses

Inflammation is often a protective reaction against harmful foreign agents. However, in many disease conditions, the mechanisms behind the inflammatory response are poorly understood. Often times, the inflammation causes adverse effects, such as joint pain, abdominal pain, fever, fatigue, and loss of appetite. Thus, many treatments aim to inhibit the inflammatory response in order to control adverse symptoms. Such treatments include TNFα inhibitors. However, a major risk associated with drugs inhibiting tumor necrosis factor alpha (TNFα) is serious infection, including tuberculosis (TB).

Anti-TNFα therapy is used to treat patients with Crohn’s disease, for which the risk of tuberculosis may be …

Improving The Detection Limit Of Tau Aggregates For Use With Biological Samples, Emily Rickman Hager

Electronic Theses and Dissertations

The protein Tau is found in neurofibrillary tangles in Alzheimer's disease and over 20 other neurodegenerative diseases. An assay has been developed to detect minute amounts of fibrils from human brain tissue. This assay subjects brain tissue extract and recombinant Tau to several rounds of sonication and incubation. Incubation allows recombinant Tau to add itself to the ends of the existing fibrils in brain tissue extract. Sonication breaks the existing fibrils in the brain tissue extract offering more ends for Tau to add onto. Cycles of sonication and incubation have been shown to allow for amplification of Tau fibrils from …

Risk Behaviors And Hiv Care Continuum Outcomes Among Criminal Justice-Involved Hiv-Infected Transgender Women And Cisgender Men: Data From The Seek, Test, Treat, And Retain Harmonization Initiative., Curt G Beckwith, Irene Kuo, Rob J Fredericksen, Lauren Brinkley-Rubinstein, William E Cunningham, Sandra A Springer, Kelsey B Loeliger, Julie Franks, Katerina Christopoulos, Jennifer Lorvick, Shoshana Y Kahana, Rebekah Young, David W Seal, Chad Zawitz, Joseph A Delaney, Heidi M Crane, Mary L Biggs

Epidemiology Faculty Publications

BACKGROUND: Transgender persons are highly victimized, marginalized, disproportionately experience incarceration, and have alarmingly increased rates of HIV infection compared to cis-gender persons. Few studies have examined the HIV care continuum outcomes among transgender women (TW), particularly TW who are involved with the criminal justice (CJ) system.

METHODS: To improve our understanding of HIV care continuum outcomes and risk behaviors among HIV-infected TW who are involved with the CJ system, we analyzed data from the National Institute on Drug Abuse-supported Seek, Test, Treat, Retain (STTR) Data Harmonization Initiative. Baseline data were pooled and analyzed from three U.S. STTR studies to examine …

Pre- And Post-Diagnosis Physical Activity, Television Viewing, And Mortality Among Hematologic Cancer Survivors., Daniela Schmid, Gundula Behrens, Hannah Arem, Christina Hart, Wolfgang Herr, Carmen Jochem, Charles E Matthews, Michael F Leitzmann

Epidemiology Faculty Publications

PURPOSE: The associations of physical activity and television (TV) viewing with mortality risk among individuals with hematologic malignancies remain unclear.

METHODS: We examined the relations of physical activity and TV viewing time before and after diagnosis with mortality among 5182 U.S. adults aged 50-71 years from the NIH-AARP Diet and Health Study cohort who survived a first primary hematologic cancer between 1995-1996 and 2011.

RESULTS: For the pre- and post-diagnosis analyses, we confirmed 2606 and 613 deaths respectively. In multivariable-adjusted Cox proportional hazard regression models, comparing high (≥4 hrs/wk) versus low (/wk) activity levels, pre-diagnosis physical activity was associated with …

Impact Of Chronic Sexual Abuse And Depression On Inflammation And Wound Healing In The Female Reproductive Tract Of Hiv-Uninfected And Hiv-Infected Women., Mimi Ghosh, Jason Daniels, Maria Pyra, Monika Juzumaite, Mariel Jais, Kerry Murphy, Tonya N Taylor, Seble Kassaye, Lorie Benning, Mardge Cohen, Kathleen Weber

Epidemiology Faculty Publications

Sexual violence is associated with increased risk of HIV acquisition/transmission in women. Forced sex can result in physical trauma to the reproductive tract as well as severe psychological distress. However, immuno-biological mechanisms linking sexual violence and HIV susceptibility are incompletely understood. Using the Women's Interagency HIV Study repository, a total of 77 women were selected to form 4 groups, stratified by HIV serostatus, in the following categories: 1) no sexual abuse history and low depressive symptom score (below clinically significant cut-off, scores

Piloting Very Early Infant Diagnosis Of Hiv In Lesotho: Acceptability And Feasibility Among Mothers, Health Workers And Laboratory Personnel., Michelle M Gill, Lynne M Mofenson, Mamakhetha Phalatse, Vincent Tukei, Laura Guay, Matsepeli Nchephe

Epidemiology Faculty Publications

INTRODUCTION: Mortality associated with in-utero HIV infection rises rapidly within weeks after birth. Very early infant diagnosis of HIV (VEID)-testing within 2 weeks of birth-followed by immediate initiation of antiretroviral therapy has potential to avert mortality associated with in-utero transmission. However, our understanding of acceptability and feasibility of VEID is limited.

METHODS: VEID was piloted in an observational prospective cohort of HIV-positive pregnant women and their infants in 13 Lesotho health facilities. Between March-July 2016, semi-structured interviews were conducted with HIV-positive women attending 6-week or 14-week postnatal visits and health workers (HWs) in 8 study facilities in 3 districts as …

Sexually Transmitted Infections Among Hiv-Infected Individuals In The District Of Columbia And Estimated Hiv Transmission Risk: Data From The Dc Cohort, Jose Lucar, Rachel Hart, Nabil Rayeed, Arpi Terzian, Amy Weintrob, Amanda D. Castel, Debra A. Benator, Dc Cohort Executive Committee

Epidemiology Faculty Publications

Background

Washington, DC, has one of the highest rates of HIV infection in the United States. Sexual intercourse is the leading mode of HIV transmission, and sexually transmitted infections (STIs) are a risk factor for HIV acquisition and transmission.

Methods

We evaluated the incidence and demographic factors associated with chlamydia, gonorrhea, and syphilis among HIV-infected persons enrolled at 13 DC Cohort sites from 2011 to 2015. Using Poisson regression, we assessed covariates of risk for incident STIs. We also examined HIV viral loads (VLs) at the time of STI diagnosis as a proxy for HIV transmission risk.

Results

Six point …

Aggressive Diuresis And Severity-Adjusted Length Of Hospital Stay In Acute Congestive Heart Failure Patients, Muhammad U. Butt

Theses and Dissertations--Clinical Research Design

To see if aggressive diuresis in first twenty four hours is associated with a comparable number of total days in the hospital as compared to non-aggressive diuresis. In this retrospective cohort study, we compared the length of hospital stay of consecutive patients admitted in one year based on their diuresis during the first twenty-four hours of hospitalization: aggressive diuresis (group 1) i.e. > 2400mL versus non-aggressive diuresis (group 2) i.e. ≤ 2400mL urine output. Patients were excluded if in cardiogenic shock, had creatinine level above 3 mg/dL on admission, or on dialysis. A total of 194 patients were enrolled (29 in …

The Impact Of Truncating Data On The Predictive Ability For Single-Step Genomic Best Linear Unbiased Prediction, Jeremy T. Howard, Thomas A. Rathje, Caitlyn E. Bruns, Danielle F. Wilson-Wells, Stephen D. Kachman, Matthew L. Spangler

Department of Animal Science: Faculty Publications

Simulated and swine industry data sets were utilized to assess the impact of removing older data on the predictive ability of selection candidate estimated breeding values (EBV) when using single-step genomic best linear unbiased prediction (ssGBLUP). Simulated data included thirty replicates designed to mimic the structure of swine data sets. For the simulated data, varying amounts of data were truncated based on the number of ancestral generations back from the selection candidates. The swine data sets consisted of phenotypic and genotypic records for three traits across two breeds on animals born from 2003 to 2017. Phenotypes and genotypes were iteratively …

Spatio-Temporal Frequency Separation With Application Of Kolmogorov-Zurbenko Filters To The Multivariate Analysis Of Melanoma Prevalence, Edward Valachovic

Legacy Theses & Dissertations (2009 - 2024)

Time Series Analysis is the observation of variables recorded across time. Observations are visualized and analysis often performed in the native time domain. It is common for a time series to be the dependent variable of more than one factor. Several factors can have concurrent and combined effects. The time domain presents an obstacle due to constructive and destructive interference of factors at each time point. Unless effects are clearly pronounced and separable, the entanglement of factors along with the presence and intensity of random variation can obscure true relationships.

Stress-Strength Estimation And Its Applications In Clinical Trials, Dinesh Kumar

Legacy Theses & Dissertations (2009 - 2024)

Stress Strength model P(X

Improved Methods And Selecting Classification Types For Time-Dependent Covariates In The Marginal Analysis Of Longitudinal Data, I-Chen Chen

Theses and Dissertations--Epidemiology and Biostatistics

Generalized estimating equations (GEE) are popularly utilized for the marginal analysis of longitudinal data. In order to obtain consistent regression parameter estimates, these estimating equations must be unbiased. However, when certain types of time-dependent covariates are presented, these equations can be biased unless an independence working correlation structure is employed. Moreover, in this case regression parameter estimation can be very inefficient because not all valid moment conditions are incorporated within the corresponding estimating equations. Therefore, approaches using the generalized method of moments or quadratic inference functions have been proposed for utilizing all valid moment conditions. However, we have found that …

Bivariate Generalization Of The Time-To-Event Conditional Reassessment Method With A Novel Adaptive Randomization Method, Donglin Yan

Theses and Dissertations--Epidemiology and Biostatistics

Phase I clinical trials in oncology aim to evaluate the toxicity risk of new therapies and identify a safe but also effective dose for future studies. Traditional Phase I trials of chemotherapies focus on estimating the maximum tolerated dose (MTD). The rationale for finding the MTD is that better therapeutic effects are expected at higher dose levels as long as the risk of severe toxicity is acceptable. With the advent of a new generation of cancer treatments such as the molecularly targeted agents (MTAs) and immunotherapies, higher dose levels no longer guarantee increased therapeutic effects, and the focus has shifted …

Improved Standard Error Estimation For Maintaining The Validities Of Inference In Small-Sample Cluster Randomized Trials And Longitudinal Studies, Whitney Ford Tanner

Theses and Dissertations--Epidemiology and Biostatistics

Data arising from Cluster Randomized Trials (CRTs) and longitudinal studies are correlated and generalized estimating equations (GEE) are a popular analysis method for correlated data. Previous research has shown that analyses using GEE could result in liberal inference due to the use of the empirical sandwich covariance matrix estimator, which can yield negatively biased standard error estimates when the number of clusters or subjects is not large. Many techniques have been presented to correct this negative bias; However, use of these corrections can still result in biased standard error estimates and thus test sizes that are not consistently at their …

Using Prescription Drug Monitoring Data To Inform Population Level Analysis Of Opioid Analgesic Utilization, Huong T. T. Luu

Theses and Dissertations--Epidemiology and Biostatistics

Increased opioid analgesic (OA) prescribing has been associated with increased risk of prescription opioid diversion, misuse, and abuse. States established prescription drug monitoring programs (PDMPs) to collect and analyze electronic records for dispensed controlled substances to reduce prescription drug abuse and diversion. PDMP data can be used by prescribers for tracking patient’s history of controlled substance prescribing to inform clinical decisions.

The studies in this dissertation are focused on the less utilized potential of the PDMP data to enhance public health surveillance to monitor OA prescribing and co-prescribing and association with opioid overdose mortality and morbidity. Longitudinal analysis of OA …

Penalized Mixed-Effects Ordinal Response Models For High-Dimensional Genomic Data In Twins And Families, Amanda E. Gentry

Theses and Dissertations

The Brisbane Longitudinal Twin Study (BLTS) was being conducted in Australia and was funded by the US National Institute on Drug Abuse (NIDA). Adolescent twins were sampled as a part of this study and surveyed about their substance use as part of the Pathways to Cannabis Use, Abuse and Dependence project. The methods developed in this dissertation were designed for the purpose of analyzing a subset of the Pathways data that includes demographics, cannabis use metrics, personality measures, and imputed genotypes (SNPs) for 493 complete twin pairs (986 subjects.) The primary goal was to determine what combination of SNPs and …

Joint Analysis Of Multiple Phenotypes In Association Studies, Xiaoyu Liang

Dissertations, Master's Theses and Master's Reports

Genome-wide association studies (GWAS) have become a very effective research tool to identify genetic variants of underlying various complex diseases. In spite of the success of GWAS in identifying thousands of reproducible associations between genetic variants and complex disease, in general, the association between genetic variants and a single phenotype is usually weak. It is increasingly recognized that joint analysis of multiple phenotypes can be potentially more powerful than the univariate analysis, and can shed new light on underlying biological mechanisms of complex diseases. Therefore, developing statistical methods to test for genetic association with multiple phenotypes has become increasingly important. …

Adjusting For Mis-Reporting In Count Data, Gelareh Rahimighazikalayeh

Theses and Dissertations

Any counting system is prone to recording errors including underreporting and overreporting. Ignoring the misreporting pattern in count data can give rise to bias in the estimation of model parameters. Accordingly, Poisson, negative binomial and generalized Poisson regression have been expanded in some instances to capture reporting biases. However, to our knowledge, no program has been developed to allow users to apply all of these models when needed. In the first part of the dissertation, we review the available models for underreported counts and develop a Stata command to estimate Poisson, negative binomial and generalized Poisson regression models for underreported …

Step-Selection Functions For Modeling Animal Movement -- Case Study: African Buffalo, Maia Adar

CMC Senior Theses

Understanding what factors influence wildlife movement allows landscape planners to make informed decisions that benefit both animals and humans. New quantitative methods, such as step-selection functions, provide valuable objective analyses of wildlife connectivity. This paper provides a framework for creating a step-selection function and demonstrates its use in a case study. The first section provides a general introduction about wildlife connectivity research. The second section explains the math behind the step-selection function using a simple example. The last section gives the results of a step-selection model for African buffalo in the Kavango Zambezi Transfrontier Conservation Area. Buffalo were found to …

Geographic Variations In Antenatal Care Services In Sierra Leone, Eunice Nyambura Chege

Walden Dissertations and Doctoral Studies

Despite antenatal care presenting opportunities to identify and monitor women at risk, use of recommended antenatal care services remains. Barriers preventing use of antenatal services vary between countries, and limited knowledge exists about the link between geographical settings and antenatal service use. The objective of this cross-sectional quantitative study was to explore geographical variations and investigate how social demographic characteristics affect use of antenatal care for women in Sierra Leone using the Andersen behavioral model. The data used were from the 2016 maternal death surveillance report of the whole counrty (N =706). Logistic regression analysis was used to determine the …

Comparison Of The Performance Of Simple Linear Regression And Quantile Regression With Non-Normal Data: A Simulation Study, Marjorie Howard

Theses and Dissertations

Linear regression is a widely used method for analysis that is well understood across a wide variety of disciplines. In order to use linear regression, a number of assumptions must be met. These assumptions, specifically normality and homoscedasticity of the error distribution can at best be met only approximately with real data. Quantile regression requires fewer assumptions, which offers a potential advantage over linear regression. In this simulation study, we compare the performance of linear (least squares) regression to quantile regression when these assumptions are violated, in order to investigate under what conditions quantile regression becomes the more advantageous method …

Estimation Procedures For Complex Survival Models And Their Applications In Epidemiology Studies, Jie Zhou

Theses and Dissertations

In this dissertation, we aim to address three important questions in practice, which can be solved through complex survival models. The first project focuses on studying the longitudinal fitness effect on cardiovascular disease (CVD) mortality. In the second project, we study the disease-death relation between CVD and all-cause mortality and evaluate important covariate effects on the disease or death transitions. In the third project, we compare antiretroviral treatment (ART) for HIV patients and consider both treatment effect and side effect of the drugs. The first two projects are motivated by the Aerobics Center Longitudinal Study (ACLS) datasets and the third …

Examining The Confirmatory Tetrad Analysis (Cta) As A Solution Of The Inadequacy Of Traditional Structural Equation Modeling (Sem) Fit Indices, Hangcheng Liu

Theses and Dissertations

Structural Equation Modeling (SEM) is a framework of statistical methods that allows us to represent complex relationships between variables. SEM is widely used in economics, genetics and the behavioral sciences (e.g. psychology, psychobiology, sociology and medicine). Model complexity is defined as a model’s ability to fit different data patterns and it plays an important role in model selection when applying SEM. As in linear regression, the number of free model parameters is typically used in traditional SEM model fit indices as a measure of the model complexity. However, only using number of free model parameters to indicate SEM model complexity …

Estimating The Respiratory Lung Motion Model Using Tensor Decomposition On Displacement Vector Field, Kingston Kang

Theses and Dissertations

Modern big data often emerge as tensors. Standard statistical methods are inadequate to deal with datasets of large volume, high dimensionality, and complex structure. Therefore, it is important to develop algorithms such as low-rank tensor decomposition for data compression, dimensionality reduction, and approximation.

With the advancement in technology, high-dimensional images are becoming ubiquitous in the medical field. In lung radiation therapy, the respiratory motion of the lung introduces variabilities during treatment as the tumor inside the lung is moving, which brings challenges to the precise delivery of radiation to the tumor. Several approaches to quantifying this uncertainty propose using a …

An Investigation Of Atomic Structures Derived From X-Ray Crystallography And Cryo-Electron Microscopy Using Distal Blocks Of Side-Chains, Lin Chen, Jing He, Salim Sazzed, Rayshawn Walker

Computer Science Faculty Publications

Cryo-electron microscopy (cryo-EM) is a structure determination method for large molecular complexes. As more and more atomic structures are determined using this technique, it is becoming possible to perform statistical characterization of side-chain conformations. Two data sets were involved to characterize block lengths for each of the 18 types of amino acids. One set contains 9131 structures resolved using X-ray crystallography from density maps with better than or equal to 1.5 Å resolutions, and the other contains 237 protein structures derived from cryo-EM density maps with 2-4 Å resolutions. The results show that the normalized probability density function of block …

Statistical Methods For Detecting Causal Rare Variants And Analyzing Multiple Phenotypes, Xinlan Yang

Dissertations, Master's Theses and Master's Reports

This dissertation includes two papers with each distributed in one chapter. To date, genome-wide association studies (GWAS) have identified a large number of common variants that are associated with complex diseases successfully. However, the common variants identified by GWAS only account for a small proportion of trait heritability. Many studies showed that rare variants could explain parts of the missing heritability. Since the well-developed common variant detecting methods are underpowered for rare variant association tests unless sample sizes or effect sizes are very large, investigation the roles of rare variants in complex diseases presents substantial challenges. In chapter 1, we …