Biostatistics Commons^™

Statistical Methods For Modern Threats, Brandon Lumsden

All Dissertations

More than ever before, technology is evolving at a rapid pace across the broad spectrum of biological sciences. As data collection becomes more precise, efficient, and standardized, a demand for appropriate statistical modeling grows as well. Throughout this dissertation, we examine a variety of new age data arising from modern technology of the 21st century. We begin by employing a suite of existing statistical techniques to address research questions surrounding three medical conditions presenting in public health sciences. Here we describe the techniques used, including generalized linear models and longitudinal models, and we summarize the significant associations identified between research …

Use Of Healthcare Utilization Records For Analyzing Trends In Clinical Toxoplasmosis: A Comparison Of Nevada And The United States, Elijah Kreutzer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Toxoplasmosis, a zoonotic disease caused by the parasitic protist Toxoplasma gondii, is a ubiquitous, global public health concern with a wide variety of clinical manifestations. Surveillance for the disease is lacking even in developed countries, and what surveillance is present most often focuses on pregnant women. This research investigated trends in clinical toxoplasmosis in Nevada and nationally to address the lack of knowledge concerning how Nevada discharges compare to national discharges in cases of toxoplasmosis. Specifically, this research sought to determine what characterizes toxoplasmosis in Nevada across inpatient, outpatient, and emergency department settings, as well as how these cases differ …

Statistical Methods For Meta-Analysis In Large-Scale Genomic Experiments, Wimarsha Thathsarani Jayanetti

Mathematics & Statistics Theses & Dissertations

Recent developments in high throughput genomic assays have opened up the possibility of testing hundreds and thousands of genes simultaneously. With the availability of vast amounts of public databases, researchers tend to combine genomic analysis results from multiple studies in the form of a meta-analysis. Meta-analysis methods can be broadly classified into two main categories. The first approach is to combine the statistical significance (pvalues) of the genes from each individual study, and the second approach is to combine the statistical estimates (effect sizes) from the individual studies. In this dissertation, we will discuss how adherence to the standard null …

The Potential Of Private Health Insurance Ownership Based On The 2018-2020 National Socioeconomic Survey Data, Arief Rosyid Hasan, Adang Bachtiar, Cicilya Candi

Kesmas

In 2014, the Indonesian Government introduced a social security program in the health sector. However, Indonesia’s out-of-pocket expenses remain high due to a lack of public interest in National Health Insurance services. Financing expensive health services with high out-of-pocket expenses has the potential to cause poverty. Private health insurance is considered a solution to this problem. This study aimed to determine the socioeconomic factors of private health insurance ownership and its potential in Indonesia. This study used secondary data from the 2018, 2019, and 2020 National Socioeconomic Surveys. Logistic regression analysis showed that the variables related to private health insurance …

A Bootstrap Method For A Multiple-Imputation Variance Estimator In Survey Sampling, Lili Yu, Yichuan Zhao

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Rubin’s variance estimator of the multiple imputation estimator for a domain mean is not asymptotically unbiased. Kim et al. derived the closed-form bias for Rubin’s variance estimator. In addition, they proposed an asymptotically unbiased variance estimator for the multiple imputation estimator when the imputed values can be written as a linear function of the observed values. However, this needs the assumption that the covariance of the imputed values in the same imputed dataset is twice that in the different imputed datasets. In this study, we proposed a bootstrap variance estimator that does not need this assumption. Both theoretical argument and …

Pandemic Fatigue Impedes Mitigation Of Covid-19 In Hong Kong, Zhanwei Du, Lin Wang, Songwei Shan, Dickson Lam, Tim K. Tsang, Jingyi Xiao, Huizhi Gao, Bingyi Yang, Sheikh Taslim Ali, Sen Pei, Isaac Chun-Hai Fung, Eric H. Y. Lau, Qiuyan Liao, Peng Wu, Lauren Ancel Meyers, Gabriel M. Leung, Benjamin Cowling

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Hong Kong has implemented stringent public health and social measures (PHSMs) to curb each of the four COVID-19 epidemic waves since January 2020. The third wave between July and September 2020 was brought under control within 2 m, while the fourth wave starting from the end of October 2020 has taken longer to bring under control and lasted at least 5 mo. Here, we report the pandemic fatigue as one of the potential reasons for the reduced impact of PHSMs on transmission in the fourth wave. We contacted either 500 or 1,000 local residents through weekly random-digit dialing of landlines …

Association Between The Health Belief Model, Exercise, And Nutrition Behaviors During The Covid-19 Pandemic, Keagan Kiely, Bill Mase, Andrew R. Hansen, Jessica S. Schwind

Biostatistics, Epidemiology & Environmental Health Sciences: Faculty Publications

Introduction: The COVID-19 pandemic has affected our nation’s health further than the infection it causes. Physical activity levels and dietary intake have suffered while individuals grapple with the changes in behavior to reduce viral transmission. With unique nuances regarding the access to physical activity and nutrition during the pandemic, the constructs of Health Belief Model (HBM) may present themselves differently in nutrition and exercise behaviors compared to precautions implemented to reduce viral transmission studied in previous research. The purpose of this study was to investigate the extent of exercise and nutritional behavior change during the COVID-19 pandemic and explain the …

Laboratory Evaluation And Field Feasibility Of Micro-Encapsulated Insecticide Effect On Rhodnius Prolixus And Triatoma Dimidiata Mortality In Rural Households In Boyaca, Colombia, Lidia Gual-Gonzalez, Manuel Medina, Cesar Valverde-Castro, Virgilio Beltran, Rodrigo Caro, Omar Triana-Chavez, Melissa Nolan Ph.D., Mph, Omar Cantillo-Barraza

Faculty Publications

Chagas disease is a neglected vector-borne zoonosis caused by the parasite Trypanosoma cruzi that is primarily transmitted by insects of the subfamily Triatominae. Although control efforts targeting domestic infestations of Rhodnius prolixus have been largely successful, with several regions in Boyacá department certified free of T. cruzi transmission by intradomicile R. prolixus, novel native species are emerging, increasing the risk of disease. Triatoma dimidiata is the second most important species in Colombia, and conventional control methods seem to be less effective. In this study we evaluated the efficacy and usefulness of micro-encapsulated insecticide paints in laboratory conditions and its …

The Dietary Inflammatory Index Is Associated With Subclinical Mastitis In Lactating European Women, Myriam C. Afeiche, Alison Iroz, Frank Thielecke, Antoino C. De Castro, Gregory Lefebvre, Colleen F. Draper, Cecilia Martiínez-Costa, Maria Jose Costeira, Mireille Vanpee, Claude Billeaud, Jean-Charles Picaud, Daryl Lim Kah Hian, Guimei Liu, Nitin Shivappa Mbbs, Mph, Ph.D., James Hébert Scd, Tinu M. Samuel

Faculty Publications

Subclinical mastitis (SCM) is an inflammatory state of the lactating mammary gland, which is asymptomatic and may have negative consequences for child growth. The objectives of this study were to: (1) test the association between the dietary inflammatory index (DII®) and SCM and (2) assess the differences in nutrient intakes between women without SCM and those with SCM. One hundred and seventy-seven women with available data on human milk (HM) sodium potassium ratio (Na:K) and dietary intake data were included for analysis. Multivariable logistic regression was used to examine the association between nutrient intake and the DII score in relation …

Antibody Prevalence And Risk Factors Associated With Rickettsia Spp. In A Pediatric Cohort: Sfgr Remains Underdiagnosed And Underreported In El Salvador, Kyndall C. Dye-Braumuller, Marvin Stanley Rodríguez Aquino, Kia Zellars, Hanna Waltz, Madeleine Meyer, Lídua Gual-Gonzalez, Stella C.W. Self, Mufaro Kanyangarara, Melissa Nolan Ph.D., Mph

Faculty Publications

Spotted fever group rickettsioses (SFGR) are caused by a group of tick-borne pathogens that are increasing in incidence globally. These diseases are typically underreported and undiagnosed in low- and middle-income countries, and thus, have been classified as neglected bacterial pathogens. Countries with high poverty, low human development index score, and limited health infrastructure—like El Salvador in Central America—lack necessary surveillance for SFGR and other tick-borne pathogens. This paucity of baseline SFGR infection prevalence leaves vulnerable populations at risk of misdiagnosis. Further, tick-borne disease burdens in El Salvador are severely limited. To lay the foundation for tick-borne disease epidemiology in El …

Process Evaluation Methods And Results From The Health In Pregnancy And Postpartum (Hipp) Randomized Controlled Trial, Sarah Wilcox Phd, Alicia A. Dahl, Alycia K. Boutté, Jihong Liu Sc.D., Kelsey Day, Gabrielle Turner-Mcgrievy Ph.D., Rd, Ellen Wingard

Faculty Publications

Background

Excessive gestational weight gain has increased over time and is resistant to intervention, especially in women living with overweight or obesity. This study described the process evaluation methods and findings from a behavioral lifestyle intervention for African American and white women living with overweight and obesity that spanned pregnancy (≤ 16 weeks gestation) through 6 months postpartum.

Methods

The Health in Pregnancy and Postpartum (HIPP) study tested a theory-based behavioral intervention (vs. standard care) to help women (N = 219; 44% African American, 29.1 ± 4.8 years) living with overweight or obesity meet weight gain guidelines in pregnancy and …

Higher Adherence To A Mediterranean Diet Is Associated With Improved Insulin Sensitivity And Selected Markers Of Inflammation In Individuals Who Are Overweight And Obese Without Diabetes, Surbhi Sood, Jack Feehan, Catherine Itsiopoulos, Kirsty Wilson, Magdalena Plebanski, David Scott, James Hébert Scd, Nitin Shivappa Mbbs, Mph, Ph.D., Aya Mousa, Elena S. George, Barbora De Courten

Faculty Publications

Insulin resistance (IR) and chronic low-grade inflammation are risk factors for chronic diseases including type 2 diabetes (T2D) and cardiovascular disease. This study aimed to investigate two dietary indices: Mediterranean Diet Score (MDS) and Dietary Inflammatory Index (DII®), and their associations with direct measures of glucose metabolism and adiposity, and biochemical measures including lipids, cytokines and adipokines in overweight/obese adults. This cross-sectional study included 65 participants (males = 63%; age 31.3 ± 8.5 years). Dietary intake via 3-day food diaries was used to measure adherence to MDS (0–45 points); higher scores indicating adherence. Energy-adjusted DII (E-DII) scores were calculated with …

The Impact Of Meal Dietary Inflammatory Index On Exercise-Induced Changes In Airway Inflammation In Adults With Asthma, Katrina P. Mcdiarmid, Lisa G. Wood, John W. Upham, Lesley K. Macdonald-Wicks, Nitin Shivappa Mbbs, Mph, Ph.D., James R. Hébert Scd, Hayley A. Scott

Faculty Publications

Research suggests exercise may reduce eosinophilic airway inflammation in adults with asthma. The Dietary Inflammatory Index (DII®) quantifies the inflammatory potential of the diet and has been associated with asthma outcomes. This study aimed to determine whether the DII of a meal consumed either before or after exercise influences exercise-induced changes in airway inflammation. A total of 56 adults with asthma were randomised to (1) 30–45 min moderate–vigorous exercise, or (2) a control group. Participants consumed self-selected meals, two hours pre- and two hours post-intervention. Energy-adjusted DII (E-DIITM) was determined for each meal, with meals then characterised as “anti-inflammatory” or …

Metabolome-Wide Associations Of Gestational Weight Gain In Pregnant Women With Overweight And Obesity, Jin Dai, Nansi S. Boghossian, Mark Sarzynski Ph.D., Faha, Facsm, Feng Luo, Xiaoqian Sun, Jian Li, Oliver Fiehn, Jihong Liu Sc.D., Liwei Chen

Faculty Publications

Excessive gestational weight gain (GWG) is associated with adverse pregnancy outcomes. This metabolome-wide association study aimed to identify metabolomic markers for GWG. This longitudinal study included 39 Black and White pregnant women with a prepregnancy body mass index (BMI) of ≥ 25 kg/m². Untargeted metabolomic profiling was performed using fasting plasma samples collected at baseline (mean: 12.1 weeks) and 32 weeks of gestation. The associations of metabolites at each time point and changes between the two time points with GWG were examined by linear and least absolute shrinkage and selection operator (LASSO) regression analyses. Pearson correlations between the …

Utilization Of 18s Ribosomal Rna Lamp For Detecting Plasmodium Falciparum In Microscopy And Rapid Diagnostic Test Negative Patients, Enoch Aninagyei, Adjoa Agyemang Boakye, Clement Okraku Tettey, Kofi Adjei Nitri, Samuel Ohene Ofori, Comfort Dede Tetteh, Thelma Teley Alphour, Tanko Rufai

Faculty Publications

In this study, Plasmodium falciparum was detected in patients that were declared negative for malaria microscopy and rapid diagnostic test kit (mRDT), using Plasmodium 18s rRNA loop-mediated isothermal amplification (LAMP) technique. The main aim of this study was to assess the usefulness of LAMP assay for detecting pre-clinical malaria, when microscopy and mRDT were less sensitive. DNA was obtained from 100 μL of whole blood using the boil and spin method. Subsequently, the Plasmodium 18s rRNA LAMP assay was performed to amplify the specific Plasmodium 18s rRNA gene. Microscopy and mRDT negative samples [697/2223 (31.2%)] were used for this study. …

Examining The Association Between A Modified Quan Charlson Comorbidity Index (Qcci) And Viral Suppression: A Cross Sectional Analysis Of Dc Cohort Participants, Hasmin C. Ramirez, Lauren O’Connor, Morgan Byrne, Anne Monroe

Epidemiology Faculty Posters and Presentations

No abstract provided.

Quality Of Life In Older And Younger People With Hiv And Diabetes, Lauren F. O’Connor, La’Marcus Wingate, Sam Simmens, Amanda D. Castel, Anne K. Monroe

Epidemiology Faculty Posters and Presentations

No abstract provided.

Cancer Incidence And Stage At Diagnosis Among People With Psychotic Disorders: Systematic Review And Meta-Analysis., Jared C Wootten, Joshua C Wiener, Phillip S Blanchette, Kelly K. Anderson

Epidemiology and Biostatistics Publications

Research regarding the incidence of cancer among people with psychotic disorders relative to the general population is equivocal, although the evidence suggests that they have more advanced stage cancer at diagnosis. We conducted a systematic review and meta-analysis to examine the incidence and stage at diagnosis of cancer among people with, relative to those without, psychotic disorders. We searched the MEDLINE, EMBASE, PsycINFO, and CINAHL databases. Articles were included if they reported the incidence and/or stage at diagnosis of cancer in people with psychotic disorders. Random effects meta-analyses were used to determine risk of cancer and odds of advanced stage …

Topics In Multilevel Mediation Analysis, Chung Li Wu

Theses and Dissertations

A proper study design assures adequate power to detect statistically significant differences. Existing power calculations for multilevel mediation analysis make a strong distributional assumption of normality. However, binary outcomes are commonly seen in real-world study. Motivated by this fact, we conduct a simulation-based power study for a multilevel mediation analysis with binary outcomes. The numbers of participants needed to achieve 80% power are summarized in tables for future reference.

Mixed-effect regression is commonly used in multilevel analysis for panel data. Yet, the estimated coefficients from the random-intercept model could represent either purely between-cluster, purely within-cluster, or weighted-average effects. Therefore, we …

Extensions Of Discrete Choice Experiment Theory For Public Health, Farahnaz Islam

Theses and Dissertations

A discrete choice experiment (DCE) allows researchers to understand how individuals value characteristics of a product or service in hypothetical scenarios and the trade-offs these individuals are willing to make between these characteristics. DCEs quickly gained traction in public health but as more researchers utilized DCEs in broader contexts, several methodological questions have arisen. This dissertation addresses some of these gaps in the literature.

One critique of DCEs is whether individuals would make the same choice in reality as they claimed they would have made in the hypothetical scenario. Perhaps the most efficient way to evaluate the predictive value of …