Biostatistics Commons^™

Survival Mediation Analysis With The Death-Truncated Mediator: The Completeness Of The Survival Mediation Parameter, An-Shun Tai, Chun-An Tsai, Sheng-Hsuan Lin

Harvard University Biostatistics Working Paper Series

In medical research, the development of mediation analysis with a survival outcome has facilitated investigation into causal mechanisms. However, studies have not discussed the death-truncation problem for mediators, the problem being that conventional mediation parameters cannot be well-defined in the presence of a truncated mediator. In the present study, we systematically defined the completeness of causal effects to uncover the gap, in conventional causal definitions, between the survival and nonsurvival settings. We proposed three approaches to redefining the natural direct and indirect effects, which are generalized forms of the conventional causal effects for survival outcomes. Furthermore, we developed three statistical …

Concordance Between Health Administrative Data And Survey-Derived Diagnoses For Mood And Anxiety Disorders, J. Edwards, A. Thind, S. Stranges, M. Chiu, Kelly K. Anderson

Epidemiology and Biostatistics Publications

Objective: To assess whether estimates of survey structured interview diagnoses of mood and anxiety disorders were concordant with diagnoses of these disorders obtained from health administrative data.

Methods: All Ontario respondents to the 2012 Canadian Community Health Survey-Mental Health (CCHS-MH) were linked to health administrative databases at ICES (formerly known as the Institute for Clinical Evaluative Sciences). Survey structured interview diagnoses were compared with health administrative data diagnoses obtained using a standardized algorithm. We used modified Poisson regression analyses to assess whether socio-demographic factors were associated with concordance between the two measures.

Results: Of the 4157 Ontarians included in our …

Recruitment Strategies For Cognitively Impaired Older Adults In Assisted Living Communities, Paige Greer, Elizabeth Hill, Katelyn Ware

Student Scholars Day Posters

It is well documented that recruiting persons with dementia for research in long term care settings is challenging (Lam, et. al. 2018). The purpose of this study is to explore recruitment techniques suggested by the National Institute on Aging (2018), including the use of brochures, community contact introductions (CCI), presentations, event tables, 1:1 interactions and activity events. We examined the success of each method of recruitment in two recruitment waves based on the number recruited in relation to the number of hours spent on that recruitment method. Of the 119 people that were screened, 47% were enrolled in the study. …

Multivariate Joint Models And Dynamic Predictions, Md Akhtar Hossain

Theses and Dissertations

The joint modeling of longitudinal and time-to-event data is an active area of statistical research that has received a lot of attention. The standard joint models, referred to as univariate joint models, allow simultaneous modeling of a single longitudinal outcome and a single time-to-event under an assumption of independent censoring. The majority of the joint modeling research in the last two decades has focused on extending and improving the univariate joint models. While many of the practical applications involve data on multivariate longitudinal outcomes and multiple timeto- events possibly informatively censored by some other terminal time-to-event, the developments of joint …

Effects Of Diabetes On The Output Of Farmer And Its Policy Implications, Syed Asif Ali Naqvi, Bilal Hussain, Syed Ale Raza Shah, Muhammad Sohail Amjad Makhdum

Kesmas

This study investigated the impact of diabetes on work performance of different farming communities from Punjab, Pakistan. This study was based on cross-sectional data. A representative sample of 374 farmers was collected from five selected districts. Three types of respondents were analyzed in the study e.g.,laborer, small and large growers. Poisson and logistic regression techniques were used for the sake of analysis. According to the investigated results for thelabor category, respondents with more age, less qualification, low earning per month (Rupees), and having positive record of family diabetes, would havemore leave per month. In the same way, findings for small …

Qualitative Exploration Of Experiences And Consequences Of Health-Related Stigma Among Indonesians With Hiv, Leprosy, Schizophrenia And Diabetes, Sarju Sing Rai, Irwanto Irwanto, Ruth M.H. Peters, Elena V. Syurina, Annisa Ika Putri, Altana Mikhakhanova, Denise Naniche, Marjolein B.M. Zweekhorst

Kesmas

Health-related stigma causes a negative impact on the lives of affected people and undermines the effectiveness of public health programs. This study aimedto explore experiences and consequences of stigma among people affected by four health conditions relevant in Indonesia– HIV (Human ImmunodeficiencyVirus), leprosy, schizophrenia and diabetes. In this qualitative study 40 people affected by the four health conditions in Jakarta and West Java, Indonesia–,were interviewed between March and June 2018. Data were analyzed thematically by following an integrative inductive-deductive approach. The experiencesand consequences of people with stigma were similar, but such experience were more severe among people affected by HIV, …

Entomological Index And Home Environment Contribution­ ­To Dengue Hemorrhagic Fever In Mataram City, Indonesia, Tri Baskoro Tunggul Satoto, Nur Alvira Pascawati, Tri Wibawa, Roger Frutos, Sylvie Maguin, I Kadek Mulyawan, Ali Wardana

Kesmas

Indonesia is a member of Southeast Asia Regional Office (SEARO) ranked the first in dengue hemorrhagic fever (DHF) problem based on incidence rate (IR) and case fatality rate (CFR). Several provinces in Indonesia experience an outbreak, one of which is the Mataram City in West Nusa Tenggara Province. Mataram City is an endemic area of DHF because the DHF cases are always found in three consecutive years with the number of cases that fluctuate and tend to increase. This study aimed to obtain factors that could be used to improve early warning systems in controlling DHF. This study used a …

Utilization Of Family Planning Contraceptives Among Women Inthe Coastal Area Of South Buru District, Maluku, 2017, Christiana Rialine Titaley, Ninik Sallatalohy

Kesmas

Maluku Province is one among provinces in Indonesia with a contraceptive prevalence rate (CPR) lower than the national average. This study aimed toexamine factors associated with the utilization of family planning contraceptives among women of reproductive age living in the coastal area of South BuruDistrict, Maluku, Indonesia. Data were derived from a household health survey conducted in five subdistricts in South Buru, e.g., Namrole, Leksula, Waesama,Kapala Madan and Ambalau Subdistricts on November 2017 by the Faculty of Medicine, Pattimura University in Ambon. Information on contraceptive usewere collected from 390 married women aged 20 - 49 years. Bivariate and multivariate logistic …

Determinants Of Stunted Children In Indonesia: A Multilevel Analysis At The Individual, Household, And Community Levels, Febri Wicaksono, Titik Harsanti

Kesmas

This study aimed to examine the risk factors of childhood undernutrition in Indonesia. Determinants of childhood stunting were examined by using the 2013 Indonesia Basic Health Research Survey dataset. A total of 76,165 children aged under 5 years were included in this study. The analysis used multivariate multilevel logistic regression to determine adjusted odds ratios (aORs). The prevalence of stunting in the sample population was 36.7%. The odds of stunting increased significantly among the under-five boys, children living in slum area, and the increase of household member (aOR = 1.11, 95 %CI: 1.06–1.15; 1.09, 95%CI: 1.04–1.15; and 1.03, 95%CI: 1.02–1.04 …

Health Risk Behaviors: Smoking, Alcohol, Drugs, And Dating Among Youths In Rural Central Java, Zahroh Shaluhiyah, Syamsulhuda Budi Musthofa, Ratih Indraswari, Aditya Kusumawati

Kesmas

Adolescents are more likely to adopt risky health behaviors, such as smoking, alcohol use, and sexual activity. This study examined the links betweensmoking, alcohol use, and risky dating behavior and analyzed how these factors influenced risky dating and other behaviors. It is expected that this studywould be used as a foundation for developing appropriate integrated intervention for multiple risk behaviors among youths. This study was an explanatory research study with a cross-sectional approach. It involved 160 youths aged 15-24 years randomly selected from purposive villages. Participants completedself-administrated questionnaires with an enumerator present. Data were analyzed using univariate, chi-square, and multiple …

Evaluation Of Program For Overcoming Intestinal Worm Infections Among Children, Henny Febriyanti, Haerawati Idris

Kesmas

Prevalence of intestinal worm infection in generall is extremely high in Indonesia among the poor population with poor sanitation. One of the government programs to address this problem is the distribution of medicines to prevent intestinal worm infections. However, the coverage of the achievement for this program is still low in several areas of public health centers in Palembang. Therefore, this study was conducted to evaluate the efficacy of the national program for preventing intestinal worm infections. The qualitative research design used evaluation model approach Context, Input, Process, and Product (CIPP) model. This study was conducted in one of health …

Asymptotic Simultaneous Estimations For Contrasts Of Quantiles, Lawrence Sethor Segbehoe, Frank Schaarschmidt, Gemechis Dilba Djira

SDSU Data Science Symposium

Although the expected value is popular, many researches in the health and social sciences involve skewed distributions and inferences concerning quantiles. Most standard multiple comparison procedures require the normality assumption. For example, few methods exist for comparing the medians of independent samples or quantiles of several distributions in general. To our knowledge, there is no general-purpose method for constructing simultaneous confidence intervals for multiple contrasts of quantiles. In this paper, we develop an asymptotic method for constructing such intervals and extend the idea to that of time-to-event data in survival analysis. Small-sample performance of the proposed method is assessed in …

Exploration Of Factors Associated With Perceptions Of Community Safety Among Youth In Hillsborough County, Florida: A Convergent Parallel Mixed-Methods Approach, Yingwei Yang

USF Tampa Graduate Theses and Dissertations

Introduction: Youth perceived safety is not only linked to crime and violence in a neighborhood but is also associated with health risk behaviors and certain neighborhood characteristics. The purpose of this mixed-methods study was to measure the co-occurring effects of individual and community risk factors by conducting a secondary data analysis using structural equation modeling (SEM) and to explore reasons for youth feeling safe/unsafe in their community using photovoice methodology.

Methods: Syndemic theory/model served as the theoretical framework to guide this mixed-methods study with a convergent parallel design. The quantitative strand (first manuscript) utilized an existing dataset collected from middle …

Comparison Of Upper Extremity Function In Women With And Women Without A History Of Breast Cancer, Mary Insana Fisher, Gilson J. Capilouto, Terry Malone, Heather M. Bush, Timothy L. Uhl

Communication Sciences and Disorders Faculty Publications

Background

Breast cancer treatments often result in upper extremity functional limitations in both the short and long term. Current evidence makes comparisons against a baseline or contralateral limb, but does not consider changes in function associated with aging.

Objective

The objective of this study was to compare upper extremity function between women treated for breast cancer more than 12 months in the past and women without cancer.

Design

This was an observational cross-sectional study.

Methods

Women who were diagnosed with breast cancer and had a mean post-surgical treatment time of 51 months (range = 12–336 months) were compared with women …

Hierarchical Clustering Analyses Of Plasma Proteins In Subjects With Cardiovascular Risk Factors Identify Informative Subsets Based On Differential Levels Of Angiogenic And Inflammatory Biomarkers, Zachary Winder, Tiffany L. Sudduth, David W. Fardo, Qiang Cheng, Larry B. Goldstein, Peter T. Nelson, Frederick A. Schmitt, Gregory A. Jicha, Donna M. Wilcock

Sanders-Brown Center on Aging Faculty Publications

Agglomerative hierarchical clustering analysis (HCA) is a commonly used unsupervised machine learning approach for identifying informative natural clusters of observations. HCA is performed by calculating a pairwise dissimilarity matrix and then clustering similar observations until all observations are grouped within a cluster. Verifying the empirical clusters produced by HCA is complex and not well studied in biomedical applications. Here, we demonstrate the comparability of a novel HCA technique with one that was used in previous biomedical applications while applying both techniques to plasma angiogenic (FGF, FLT, PIGF, Tie-2, VEGF, VEGF-D) and inflammatory (MMP1, MMP3, MMP9, IL8, TNFα) protein data to …

Mentoring Multi-College Bystander Efficacy Evaluation – An Approach To Growing The Next Generation Of Gender-Based Interpersonal Violence Intervention And Prevention (Vip) Researchers, Ann L. Coker, Danielle Davidov, Heather M. Bush, Emily R. Clear

Obstetrics and Gynecology Faculty Publications

The Centers for Disease Control and Prevention provided funding (U01 CE002668) to evaluate bystander program efficacy to reduce gender-based violence on college campuses (Aim 1) and to create a mentoring network (Aim 2) for young campus-based researchers interested in violence intervention or prevention (VIP). While an evaluation of this mentoring program is ongoing, our purpose here was to document the strategies used to create, implement, and begin evaluation of this national multi-college mentoring network. As each public college was recruited into this evaluation named multi-college Bystander Efficacy Evaluation (mcBEE), each college was invited to nominate a researcher interested in receiving …

Estimating Marginal Hazard Ratios By Simultaneously Using A Set Of Propensity Score Models: A Multiply Robust Approach, Di Shu, Peisong Han, Rui Wang, Sengwee Toh

Harvard University Biostatistics Working Paper Series

The inverse probability weighted Cox model is frequently used to estimate marginal hazard ratios. Its validity requires a crucial condition that the propensity score model is correctly specified. To provide protection against misspecification of the propensity score model, we propose a weighted estimation method rooted in empirical likelihood theory. The proposed estimator is multiply robust in that it is guaranteed to be consistent when a set of postulated propensity score models contains a correctly specified model. Our simulation studies demonstrate satisfactory finite sample performance of the proposed method in terms of consistency and efficiency. We apply the proposed method to …

Hypercholesterolemia Accelerates Both The Initiation And Progression Of Angiotensin Ii-Induced Abdominal Aortic Aneurysms, Jing Liu, Hisashi Sawada, Deborah A. Howatt, Jessica J. Moorleghen, Olga A. Vsevolozhskaya, Alan Daugherty, Hong S. Lu

Pharmacology and Nutritional Sciences Faculty Publications

Objective: This study determined whether hypercholesterolemia would contribute to both the initiation and progression of angiotensin (Ang)II-induced abdominal aortic aneurysms (AAAs) in mice.

Methods and Results: To determine whether hypercholesterolemia accelerates the initiation of AAAs, male low-density lipoprotein (LDL) receptor -/- mice were either fed one week of Western diet prior to starting AngII infusion or initiated Western diet one week after starting AngII infusion. During the first week of AngII infusion, mice fed normal diet had less luminal expansion of the suprarenal aorta compared to those initiated Western diet after the first week of AngII infusion. The two groups …

Estimation Of Conditional Power For Cluster-Randomized Trials With Interval-Censored Endpoints, Kaitlyn Cook, Rui Wang

Harvard University Biostatistics Working Paper Series

Cluster-randomized trials (CRTs) of infectious disease preventions often yield correlated, interval-censored data: dependencies may exist between observations from the same cluster, and event occurrence may be assessed only at intermittent clinic visits. This data structure must be accounted for when conducting interim monitoring and futility assessment for CRTs. In this article, we propose a flexible framework for conditional power estimation when outcomes are correlated and interval-censored. Under the assumption that the survival times follow a shared frailty model, we first characterize the correspondence between the marginal and cluster-conditional survival functions, and then use this relationship to semiparametrically estimate the cluster-specific …

The Undergraduate Student’S Guide To Geometric Morphometrics, Erika Crispo

Open Educational Resources

Embarking on a new research endeavor can be a daunting task. User guides, books, and published articles are written for an audience that already has some background experience in the field. Undergraduate students like you, who are at the very beginning of their research careers, often struggle to make sense of these documents. Furthermore, students like you often attempt to do so while balancing heavy course loads. Thus, I have written this document to help ease the burden so that you have more time to ponder the interesting scientific questions instead of digging through pages upon pages of documentation. I …