Public Health Commons^™

On The Definition Of A Confounder, Tyler J. Vanderweele, Ilya Shpitser

COBRA Preprint Series

The causal inference literature has provided a clear formal definition of confounding expressed in terms of counterfactual independence. The causal inference literature has not, however, produced a clear formal definition of a confounder, as it has given priority to the concept of confounding over that of a confounder. We consider a number of candidate definitions arising from various more informal statements made in the literature. We consider the properties satisfied by each candidate definition, principally focusing on (i) whether under the candidate definition control for all "confounders" suffices to control for "confounding" and (ii) whether each confounder in some context …

Spatio-Temporal Modeling Of Arthropod-Borne Zoonotic Diseases: A Proposed Methodology To Enhance Macro-Scale Analyses, Stephen Jones

All Dissertations

Zoonotic diseases are infectious diseases that can be transmitted from or through animals to humans, and arthropods often act as vectors for transmission. Emerging infectious diseases have been increasing both in prevalence and geographic range at alarming rates the last 30 years, and the majority of these diseases are zoonotic in nature. Many zoonotic diseases are considered notifiable by the Centers for Disease Control and Prevention (CDC). However, though state regulations or contractual obligations may require the reporting of certain diseases, significant underreporting is known to exist. Because of the rich volume of information captured in health insurance plan databases, …

Spatial Distribution Of Obesity Among West Virginia 5th Grade Children: Analysis Of The Socioeconomic, Physical, And Personal Environment, Sherry Roper

Theses and Dissertations (ETD)

Childhood obesity defined as a body mass index (BMI) at or above the 95th percentile for children of the same age and sex, is considered an epidemic in the United States. Biology and lifestyle behaviors have been identified as important factors in the development of childhood obesity; however, researchers are beginning to place more emphasis upon the impact that continual environmental exposures have upon obesity development. Environmental risk factors associated with obesity are distributed continuously over space, yet evidence suggests that burden of risk may not be evenly dispersed across a community. West Virginia (WV), a rural Appalachian community has …

A Comparative Study Of Indicator Bacteria Present In Ice And Soda From Las Vegas Food Establishments, Kimberly Jo Hertin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial analysis has long been used as an indicator of water quality. Since the passing of the Safe Drinking Water Act in 1974, microbial standards have been strictly set by the Environmental Protection Agency (EPA) to ensure that the public health is protected from bacterial pathogens. The bacteriological quality of water generally deteriorates as it travels from water treatment facilities through the main distribution system and into private plumbing and distribution systems. For example, Heterotrophic Plate Count (HPC) values typically increase once the water has entered plumbing devices such as beverage vending machines. Upon reaching a private facility, the opportunity …

Evaluation Of The Pilot Program, Pediatric Early Warning Sentinel Surveillance Program (Pewss), And Its Efficacy In Monitoring Pediatric Illness In Clark County, Nevada, Michelle Lee Lutman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The influenza outbreak that occurred during 2009 stimulated the formation of several surveillance programs throughout the country. The majority monitor only influenza; however, there are several other circulating respiratory pathogens, especially within the pediatric community. These other respiratory pathogens cause a variety of illnesses, such as bronchitis, pneumonia, croup, etc. Prior research has provided the medical community with valuable information about respiratory illnesses, especially those which afflict pediatric patients. Areas of knowledge including seasonality, demographics, signs and symptoms, prevention measures, and pathogenicity, have been greatly expanded over the years. This information has been of tremendous help to the medical community …

Analysis Of The Morbidity And Mortality Of Severe Influenza Infection In Clark County, Nevada For The 2010--2011 Influenza Season, Kindra Maureen St. Jacques

UNLV Theses, Dissertations, Professional Papers, and Capstones

Influenza circulates in the community in a fairly predictable manner each year; however, throughout the duration of any influenza season, influenza strains have the ability to evolve through antigenic mutations, viral reassortment, development of anti-viral resistance, and alterations in virulence. These changes are likely to cause illness among the unimmunized and can result in severe illness or death. Therefore, it is especially important to closely monitor severe influenza-associated hospitalizations and deaths. The University of Nevada, Las Vegas in collaboration with the Southern Nevada Health District (SNHD), Office of Epidemiology (OOE) analyzed data from the severe hospitalized influenza morbidity and mortality …

Exploration And Comparison Of Methods For Combining Population- And Family-Based Genetic Association Using The Genetic Analysis Workshop 17 Mini-Exome, David W. Fardo, Anthony R. Druen, Jinze Liu, Lucia Mirea, Claire Infante-Rivard, Patrick Breheny

Biostatistics Faculty Publications

We examine the performance of various methods for combining family- and population-based genetic association data. Several approaches have been proposed for situations in which information is collected from both a subset of unrelated subjects and a subset of family members. Analyzing these samples separately is known to be inefficient, and it is important to determine the scenarios for which differing methods perform well. Others have investigated this question; however, no extensive simulations have been conducted, nor have these methods been applied to mini-exome-style data such as that provided by Genetic Analysis Workshop 17. We quantify the empirical power and false-positive …

Assessing Association For Bivariate Survival Data With Interval Sampling: A Copula Model Approach With Application To Aids Study, Hong Zhu, Mei-Cheng Wang

Johns Hopkins University, Dept. of Biostatistics Working Papers

In disease surveillance systems or registries, bivariate survival data are typically collected under interval sampling. It refers to a situation when entry into a registry is at the time of the first failure event (e.g., HIV infection) within a calendar time interval, the time of the initiating event (e.g., birth) is retrospectively identified for all the cases in the registry, and subsequently the second failure event (e.g., death) is observed during the follow-up. Sampling bias is induced due to the selection process that the data are collected conditioning on the first failure event occurs within a time interval. Consequently, the …

An Examination Of Diet, Acculturation And Risk Factors For Heart Disease Among Jamaican Immigrants, Carol Renee Oladele

USF Tampa Graduate Theses and Dissertations

Background: The South Florida region is home to over 85,000 Jamaican immigrants. Yet, little is known about the dietary intakes and predictors of risk of disease within this immigrant group. An assessment of dietary intakes and the development of dietary intake methodologies specific to the Jamaican population was important as it permitted accurate estimation of the nutrient intakes of this immigrant population whose dietary habits are not well documented. In addition, nothing is known about the prevalence of risk factors for heart disease or factors influencing risk factors among this immigrant group. The purpose of this study was to assess …

Large-Scale Use Of Mosquito Larval Source Management For Malaria Control In Africa: A Cost Analysis, Eve Worrall, Ulrike Fillinger

All Peer-Reviewed Publications

Background: At present, large-scale use of two malaria vector control methods, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) is being scaled up in Africa with substantial funding from donors. A third vector control method, larval source management (LSM), has been historically very successful and is today widely used for mosquito control globally, except in Africa. With increasing risk of insecticide resistance and a shift to more exophilic vectors, LSM is now under re-evaluation for use against afro-tropical vector species. Here the costs of this intervention were evaluated. Methods. The 'ingredients approach' was used to estimate the economic and …

Characterization Of Street Food Consumption In Palermo: Possible Effects On Health, Silvio Buscemi, Annamaria Barile, Vincenza Maniaci, John A. Batsis

Dartmouth Scholarship

Background: Street Food (SF) consists of out-of-home food consumption and has old, historical roots with complex social-economic and cultural implications. Despite the emergence of modern fast food, traditional SF persists worldwide, but the relationship of SF consumption with overall health, well-being, and obesity is unknown.

Methods: This is an observational, cross-sectional study. The study was performed in Palermo, the largest town of Sicily, Italy. Two groups were identified: consumers of SF (n = 687) and conventional restaurant food (RES) consumers (n = 315). Study subjects answered a questionnaire concerning their health conditions, nutritional preferences, frequency of consumption of SF and …

Prevalensi Dan Determinan Sindrom Metabolik Pada Kelompok Eksekutif Di Jakarta Dan Sekitarnya, Sudijanto Kamso, Purwantyastuti Purwantyastuti, Dharmayati Utoyo Lubis, Ratna Juwita, Yull Kurnia Robbi, Besral Besral

Kesmas

Data tentang faktor-faktor yang berhubungan dengan sindrom metabolik pada kelompok eksekutif di Indonesia yang diperlukan untuk upaya pencegahan penyakit kardiovaskular sangat terbatas. Penelitian ini bertujuan untuk mengetahui prevalensi dan determinan sindrom metabolik pada kelompok eksekutif. Penelitian dilakukan di Jakarta dan sekitarnya dengan menggunakan rancangan cross sectional. Jumlah responden yaitu 220 orang eksekutif laki-laki dan 68 orang eksekutif wanita. Pengumpulan data dilakukan dengan pengukuran antropometri, analisis biokimia darah, analisis asupan makanan, pengukuran angka stres, dan pengukuran indeks aktivitas. Analisis regresi logistik ganda dilakukan untuk mengetahui hubungan beberapa independen variabel dengan dependen variabel. Analisis ini menghasilkan indeks massa tubuh (overweight, odds ratio …

Depicting Estimates Using The Intercept In Meta-Regression Models: The Moving Constant Technique, Blair T. Johnson Dr., Tania B. Huedo-Medina Dr.

CHIP Documents

In any scientific discipline, the ability to portray research patterns graphically often aids greatly in interpreting a phenomenon. In part to depict phenomena, the statistics and capabilities of meta-analytic models have grown increasingly sophisticated. Accordingly, this article details how to move the constant in weighted meta-analysis regression models (viz. “meta-regression”) to illuminate the patterns in such models across a range of complexities. Although it is commonly ignored in practice, the constant (or intercept) in such models can be indispensible when it is not relegated to its usual static role. The moving constant technique makes possible estimates and confidence intervals at …

Heterogeneity And Data Analysis, Peter J. Taylor

Working Papers on Science in a Changing World

This working paper is a discussion paper for a September 2011 meeting of the research group of Prof. Di Cook on data visualization and exploratory data analysis at Iowa State University. A taxonomy of eleven kinds of heterogeneity is presented, followed by a set of vignettes that illustrate some of the meanings and sketch some implications, then a series of images that illustrate the heterogeneities. Several of the vignettes speak to a broad contention about heterogeneity and control: In relation to modern understandings of heredity and development over the life course, research and application of resulting knowledge are untroubled by …

A Regularization Corrected Score Method For Nonlinear Regression Models With Covariate Error, David M. Zucker, Malka Gorfine, Yi Li, Donna Spiegelman

Harvard University Biostatistics Working Paper Series

No abstract provided.

Estimation Of Risk Ratios In Cohort Studies With Common Outcomes: A Simple And Efficient Two-Stage Approach, Eric J. Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.

On The Nondifferential Misclassification Of A Binary Confounder, Elizabeth L. Ogburn, Tyler J. Vanderweele

COBRA Preprint Series

Abstract Consider a study with binary exposure, outcome, and confounder, where the confounder is nondifferentially misclassified. Epidemiologists have long accepted the unproven but oft-cited result that, if the confounder is binary, odds ratios, risk ratios, and risk differences which control for the mismeasured confounder will lie between the crude and the true measures. In this paper the authors provide an analytic proof of the result in the absence of a qualitative interaction between treatment and confounder, and demonstrate via counterexample that the result need not hold when there is a qualitative interaction between treatment and confounder. They also present an …

Hiv And Concurrent Sexual Partnerships: Modelling The Role Of Coital Dilution, Larry Sawers, Alan G. Isaac, Eileen Stillwaggon

Economics Faculty Publications

Background: The concurrency hypothesis asserts that high prevalence of overlapping sexual partnerships explains extraordinarily high HIV levels in sub-Saharan Africa. Earlier simulation models show that the network effect of concurrency can increase HIV incidence, but those models do not account for the coital dilution effect (nonprimary partnerships have lower coital frequency than primary partnerships).

Methods: We modify the model of Eaton et al (AIDS and Behavior, September 2010) to incorporate coital dilution by assigning lower coital frequencies to non-primary partnerships. We parameterize coital dilution based on the empirical work of Morris et al (PLoS ONE, December …

Modification By Frailty Status Of Ambient Air Pollution Effects On Lung Function In Older Adults In The Cardiovascular Health Study, Sandrah P. Eckel, Thomas A. Louis, Paulo H.M. Chaves, Linda P. Fried, Helene G. Margolis

Johns Hopkins University, Dept. of Biostatistics Working Papers

Older adult susceptibility to air pollution health effects is well-recognized. Advanced age may act as a partial surrogate for conditions associated with aging. The authors investigated whether gerontologic frailty (a clinical health status metric) modified the effects of ambient ozone or particulate matter (PM10) air pollution on lung function in 3382 older adults using 7 years of followup data from the Cardiovascular Health Study (CHS) and the CHS Environmental Factors Ancillary Study. Monthly average pollution and annual frailty assessments were related to up to 3 repeated measurements of lung function using novel cumulative summaries of pollution and frailty histories that …

A Comparison Of Spatio-Temporal Prediction Methods Of Cancer Incidence In The U.S, Michelle Hamlyn

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cancer is the cause of one out of four deaths in the United States, and in 2009, researchers expected over 1.5 million new patients to be diagnosed with some form of cancer. People diagnosed with cancer, whether a common or rare type, need to undergo treatments, the amount and kind of which will depend on the severity of the cancer. So how do healthcare providers know how much funding is needed for treatment? What would better enable a pharmaceutical company to determine how much to allocate for research and development of drugs, the amount of each drug to manufacture, or …

Gene By Bmi Interactions Influencing C-Reactive Protein Levels In European-Americans, Sarah Tudor

Dissertations and Theses (Open Access)

C-Reactive Protein (CRP) is a biomarker indicating tissue damage, inflammation, and infection. High-sensitivity CRP (hsCRP) is an emerging biomarker often used to estimate an individual’s risk for future coronary heart disease (CHD). hsCRP levels falling below 1.00 mg/l indicate a low risk for developing CHD, levels ranging between 1.00 mg/l and 3.00 mg/l indicate an elevated risk, and levels exceeding 3.00 mg/l indicate high risk. Multiple Genome-Wide Association Studies (GWAS) have identified a number of genetic polymorphisms which influence CRP levels. SNPs implicated in such studies have been found in or near genes of interest including: CRP, APOE, APOC, IL-6, …

Heterogeneity, Control, Social Infrastructure, And Possibilities Of Participation: Their Interplay In Modern Understandings Of Heredity And In Interpretation Of Science, Peter J. Taylor

Working Papers on Science in a Changing World

This working paper is a prospectus for research, writing, and engagement. It consists of vignettes, sketches of lines of inquiry, and proposals for engagement, all of which concern modern understandings of heredity and development over the life course as well as the social interpretation of science. The various items address a range of areas of science and of its interpretation: heritability studies, the social uses of genetic information, gene-by-environment interaction, personalized medicine, IQ paradoxes, racial group membership, biobanks, and life events and difficulties research. Fresh perspectives in these areas are opened up by examining the ways that research and application …

Variable Importance Analysis With The Multipim R Package, Stephan J. Ritter, Nicholas P. Jewell, Alan E. Hubbard

U.C. Berkeley Division of Biostatistics Working Paper Series

We describe the R package multiPIM, including statistical background, functionality and user options. The package is for variable importance analysis, and is meant primarily for analyzing data from exploratory epidemiological studies, though it could certainly be applied in other areas as well. The approach taken to variable importance comes from the causal inference field, and is different from approaches taken in other R packages. By default, multiPIM uses a double robust targeted maximum likelihood estimator (TMLE) of a parameter akin to the attributable risk. Several regression methods/machine learning algorithms are available for estimating the nuisance parameters of the models, including …

Reduced Bayesian Hierarchical Models: Estimating Health Effects Of Simultaneous Exposure To Multiple Pollutants, Jennifer F. Bobb, Francesca Dominici, Roger D. Peng

Johns Hopkins University, Dept. of Biostatistics Working Papers

Quantifying the health effects associated with simultaneous exposure to many air pollutants is now a research priority of the US EPA. Bayesian hierarchical models (BHM) have been extensively used in multisite time series studies of air pollution and health to estimate health effects of a single pollutant adjusted for potential confounding of other pollutants and other time-varying factors. However, when the scientific goal is to estimate the impacts of many pollutants jointly, a straightforward application of BHM is challenged by the need to specify a random-effect distribution on a high-dimensional vector of nuisance parameters, which often do not have an …

Characterization Of The Serologic Responses To Plasmodium Vivax Dbpii Variants Among Inhabitants Of Pursat Province, Cambodia, Samantha Jones Barnes

USF Tampa Graduate Theses and Dissertations

The Plasmodium vivax Duffy Binding Protein (DBP) is the ligand in the major pathway for P. vivax invasion of human reticulocytes, making it an appealing vaccine candidate. Region II of DBP (DBP-RII) is the minimal portion of the ligand that mediates recognition of the Duffy Antigen Receptor for Chemokines (DARC receptor) on the reticulocyte surface and constitutes the primary vaccine target. Analysis of natural variation in the coding sequences of DBP-RII revealed signature evidence for selective pressure driving variation in the residues of the putative receptor-binding site. We hypothesize that anti-DBP immunity in P. vivax infections is strain-specific and hindered …

Principal Component Analysis Of Dietary And Lifestyle Patterns In Relation To Risk Of Subtypes Of Esophageal And Gastric Cancer, Stephanie A. Navarro Silvera, Susan T. Mayne, Harvey A. Risch, Marilie D. Gammon, Thomas Vaughan, Wong-Ho Chow, Joel A. Dubin, Robert Dubrow, Janet Schoenberg, Janet L. Stanford, A. Brian West, Heidrun Rotterdam, William J. Blot

Department of Public Health Scholarship and Creative Works

Purpose

To carry out pattern analyses of dietary and lifestyle factors in relation to risk of esophageal and gastric cancers.

Methods

We evaluated risk factors for esophageal adenocarcinoma (EA),esophageal squamous cell carcinoma(ESCC), gastric cardia adenocarcinoma (GCA), and other gastric cancers (OGA) using data from a population-based case-control study conducted in Connecticut, New Jersey, and western Washington state. Dietary/lifestyle patterns were created using principal component analysis (PCA). The impact of the resultant scores on cancer risk was estimated through logistic regression.

Results

PCA identified six patterns: meat/nitrite, fruit/vegetable, smoking/alcohol, legume/meat alternate, GERD/BMI, and fish/vitamin C. Risk of each cancer under study …

Farmwork-Related Injury Among Farmers 50 Years Of Age And Older In Kentucky And South Carolina: A Cohort Study, 2002-2005, Jennifer L. Marcum, Steven R. Browning, Deborah B. Reed, Richard Charnigo

Epidemiology and Environmental Health Faculty Publications

Farmers in the U.S. are becoming more diverse; the average age of the farmer is increasing, as is the number of women and minority farm operators. There is limited research on injury risk factors in these special populations of farmers. It is especially important to study the risk factors for injury in these growing and at-risk groups. A longitudinal survey was conducted of farmers (n = 1,394) age 50 and older who resided in Kentucky and South Carolina. The questionnaire was administered by telephone and mail surveys four times between 2002 and 2005 to the fixed cohort of farmers, obtained …

Studi Kematian Ibu Dan Kematian Bayi Di Provinsi Sumatera Barat: Faktor Determinan Dan Masalahnya, Ulvi Mariati, Z Agus, D Sulin, Masrul Masrul, Z Amri, F Arasy, Muslim Muslim, H Hanum, Mohanis Mohanis, F Arma

Kesmas

Salah satu tujuan yang hendak dicapai oleh World Health Organization pada tahun 2000 adalah health for all by year 2000. Beberapa indikator digunakan untuk mengukur pencapaian tersebut, diantaranya angka kematian bayi (AKB) dan angka kematian ibu (AKI). Dinas Kesehatan Sumatera Barat telah berhasil menurunkan AKB dan AKI selama 5 tahun terakhir, akan tetapi angka-angka tersebut tidak menggambarkan angka yang sebenarnya karena hanya diperoleh berdasarkan prediksi perhitungan statistik kependudukan. Angka tersebut juga tidak dapat memperlihatkan disparitas antarwilayah dan kelompok sosial ekonomi di Sumatera Barat. Penelitian ini dilakukan untuk mendapatkan AKB dan AKI yang tepat serta mengetahui faktor determinan dan permasalahannya di …

Perbandingan Rapid Diagnostic Test Dan Pemeriksaan Mikroskopik Pada Diagnosis Malaria, Lombok Siahaan

Kesmas

Penelitian ini dilakukan untuk membandingkan penggunaan Rapid diagnostic test dengan pemeriksaan mikroskopik (apusan darah) dalam menegakkan diagnosis malaria. Penelitian uji diagnostik ini dilakukan di Kabupaten Nias Selatan dan Kotamadya Sabang, Sumatera Utara. Apusan darah diwarnai dengan larutan Giemsa 10% dan dibaca oleh pemeriksa yang sudah terlatih. Rapid diagnostic test dilakukan dengan menggunakan parascreen. Uji diagnostik rapid diagnostic test secara umum diperoleh hasil yaitu sensitivitas 63,8%; spesifisitas 100%; Positive Predictive Value (PPV) 100%; dan negative predictive value (NPV) 93,5%. Kepadatan parasit pada rapid diagnostic test (+) dan mikroskopik (+) adalah 1.483 ± 583 parasit/μl. Sementara, kepadatan parasit pada pemeriksaan rapid diagnostic …

Faktor Risiko Kanker Serviks Di Rumah Sakit Umum Pemerintah Dr. Wahidin Sudirohusodo Makassar, Sulawesi Selatan, Sri Syatriani

Kesmas

Kanker serviks adalah tumor ganas terbanyak pada perempuan di seluruh dunia termasuk Indonesia. Jumlah penderita kanker serviks di Rumah Sakit Umum Pemerintah Dr. Wahidin Sudirohusodo pada tahun 2007 sebanyak 231 kasus, menurun menjadi 220 kasus tahun 2008 dan menurun sebanyak 167 kasus pada tahun 2009. Tujuan penelitian ini adalah untuk melihat besar risiko kejadian kanker serviks terhadap penggunaan pembalut, penggunaan sabun, status ekonomi, dan pasangan pria yang tidak disirkumsisi. Jenis penelitian adalah penelitian observasional analitik dengan desain kasus kontrol. Sampel adalah pasien yang berkunjung ke bagian ginekologi yang diambil secara accidental sampling sebanyak 213 orang. Pengumpulan data dilakukan dengan wawancara …