Epidemiology Commons^™

A Small Sample Correction For Estimating Attributable Risk In Case-Control Studies, Daniel B. Rubin

U.C. Berkeley Division of Biostatistics Working Paper Series

The attributable risk, often called the population attributable risk, is in many epidemiological contexts a more relevant measure of exposure-disease association than the excess risk, relative risk, or odds ratio. When estimating attributable risk with case-control data and a rare disease, we present a simple correction to the standard approach making it essentially unbiased, and also less noisy. As with analogous corrections given in Jewell (1986) for other measures of association, the adjustment often won't make a substantial difference unless the sample size is very small or point estimates are desired within fine strata, but we discuss the possible utility …

Spatial Misalignment In Time Series Studies Of Air Pollution And Health Data, Roger D. Peng, Michelle L. Bell

Johns Hopkins University, Dept. of Biostatistics Working Papers

Time series studies of environmental exposures often involve comparing daily changes in a toxicant measured at a point in space with daily changes in an aggregate measure of health. Spatial misalignment of the exposure and response variables can bias the estimation of health risk and the magnitude of this bias depends on the spatial variation of the exposure of interest. In air pollution epidemiology, there is an increasing focus on estimating the health effects of the chemical components of particulate matter. One issue that is raised by this new focus is the spatial misalignment error introduced by the lack of …

Nonparametric Regression Using Local Kernel Estimating Equations For Correlated Failure Time Data, Zhangsheng Yu, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

A Comparison Of Methods For Estimating The Causal Effect Of A Treatment In Randomized Clinical Trials Subject To Noncompliance, Rod Little, Qi Long, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

Semiparametric Maximum Likelihood Estimation In Normal Transformation Models For Bivariate Survival Data, Yi Li, Ross L. Prentice, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

Doubly Robust Ecological Inference, Daniel B. Rubin, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

The ecological inference problem is a famous longstanding puzzle that arises in many disciplines. The usual formulation in epidemiology is that we would like to quantify an exposure-disease association by obtaining disease rates among the exposed and unexposed, but only have access to exposure rates and disease rates for several regions. The problem is generally intractable, but can be attacked under the assumptions of King's (1997) extended technique if we can correctly specify a model for a certain conditional distribution. We introduce a procedure that it is a valid approach if either this original model is correct or if we …

Is Reporting On Interventions A Weak Link In Understanding How And Why They Work? A Preliminary Exploration Using Community Heart Health Exemplars, Barbara Riley, Joanne Macdonald, Omaima Mansi, Anita Kothari, Donna Kurtz, Linda Vontettenborn, Nancy Edwards

Anita Kothari

Background: The persistent gap between research and practice compromises the impact of multi-level and multi-strategy community health interventions. Part of the problem is a limited understanding of how and why interventions produce change in population health outcomes. Systematic investigation of these intervention processes across studies requires sufficient reporting about interventions. Guided by a set of best processes related to the design, implementation, and evaluation of community health interventions, this article presents preliminary findings of intervention reporting in the published literature using community heart health exemplars as case examples.

Methods: The process to assess intervention reporting involved three steps: selection of …

Fighting Nuclear Waste At Skull Valley, Margene Bullcreek

Native American Forum on Nuclear Issues

Abstract:

-Reasons We Oppose Nuclear Waste

-Sovereignty

-Traditional values must be protected

-Protect sacredness of our culture, plants,

animals, air, and water

-Affects on community health

-Protect reservation and homeland

-To protect the air and water

-To protect future generations

-Environmental Justice

Targeted Methods For Biomarker Discovery, The Search For A Standard, Catherine Tuglus, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

More often than not biomarker studies analyze large quantities of variables with complicated and generally unknown correlation structure. There are numerous statistical methods which attempt to unravel these variables and determine the underlying mechanism through identification of causally related biomarkers. Results from these methods are generally difficult to interpret and nearly impossible to compare across studies. The FDA has currently called for a standardization of methods and protocol for biomarker detection. In response, we propose targeted variable importance (tVIM) as a standardized method for biomarker discovery. Through the use of targeted Maximum Likelihood, tVIM provides double robust estimates of variable …

Marginal Structural Models For Partial Exposure Regimes, Stijn Vansteelandt, Karl Mertens, Carl Suetens, Els Goetghebeur

Harvard University Biostatistics Working Paper Series

Intensive care unit (ICU) patients are ell known to be highly susceptible for nosocomial (i.e. hospital-acquired) infections due to their poor health and many invasive therapeutic treatments. The effects of acquiring such infections in ICU on mortality are however ill understood. Our goal is to quantify these effects using data from the National Surveillance Study of Nosocomial Infections in Intensive Care

Units (Belgium). This is a challenging problem because of the presence of time-dependent confounders (such as exposure to mechanical ventilation)which lie on the causal path from infection to mortality. Standard statistical analyses may be severely misleading in such settings …

Mapping As A Knowledge Translation Tool For Ontario Early Years Centres: Views From Data Analysts And Managers, Anita Kothari, S. Michelle Driedger, Julia Bickford, Jason Morrison, Michael Sawada, Ian D. Graham, Eric Crighton

Anita Kothari

Background: Local Ontario Early Years Centres (OEYCs) collect timely and relevant local data, but knowledge translation is needed for the data to be useful. Maps represent an ideal tool to interpret local data. While geographic information system (GIS) technology is available, it is less clear what users require from this technology for evidence-informed program planning. We highlight initial challenges and opportunities encountered in implementing a mapping innovation (software and managerial decision-support) as a knowledge translation strategy.

Methods: Using focus groups, individual interviews and interactive software development events, we taped and transcribed verbatim our interactions with nine OEYCs in Ontario, Canada. …

Estimation Of Controlled Direct Effects, Sylvie Goetgeluk, Stijn Vansteelandt, Els Goetghebeur

Harvard University Biostatistics Working Paper Series

No abstract provided.

A Spatial Sirs Boolean Network Model For The Spread Of H5n1 Avian Influenza Virus Among Poultry Farms, Alexander Kasyanov, Leona Kirkland, Mihaela Teodora Matache

Mathematics Faculty Proceedings & Presentations

To predict the spread of Avian Influenza we propose a synchronous Susceptible-Infected-Recovered-Susceptible (SIRS) Boolean network of poultry farms, using probabilistic Boolean rules. Gravity models from transportation theory are used for the probability of infection of a node in one time step, taking into account farm sizes, distances be- tween farms, and mean distance travelled by birds. Basic reproduction numbers are computed analytically and numerically. The dynamics of the network are analyzed and various statistics considered such as number of infected nodes or time until eradication of the epidemic. We conclude that mostly when large farms (eventually) become infected the epidemic …

Dosimetric Evaluation Of Helical Tomotherapy Treatment Planning For Non-Small Cell Lung Cancer, Karen Chu, George Rodrigues, Slav Yartsev, A. Rashid Dar, Edward Yu, Robert Ash, Brian Yaremko, Marc Mackenzie, Harvey Quon, Glenn Bauman, Wilson Roa

Edward Yu

Helical tomotherapy (HT) is a novel technique to deliver intensity modulated radiation therapy guided by 3D megavoltage CT imaging. The purpose of our study is to assess the dosimetric parameters related to HT and 3DCRT in advanced non-small cell lung cancer (NSCLC). Eleven patients from the London Regional Cancer Centre and the Cross Cancer Institute with NSCLC underwent individualized treatment planning on both HT and 3DCRT. Corresponding HT and 3DCRT plans for each patient were analyzed using dose-volume histograms for GTV, PTV (median dose 60Gy/30 fractions), and critical structures (lung V5-30, esophageal V50-60, and spinal cord D1). Observed differences in …