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Ashley I Naimi, Robert W Platt, Jacob C Larkin
Birthweight is often used as a proxy for fetal weight. Problems with this practice have recently been brought to light. We explore whether data available at birth can be used to predict estimated fetal weight using linear and quantile regression, random forests, Bayesian additive regression trees, and generalized boosted models. We train and validate each approach using 18,517 pregnancies (31,948 ultrasound visits) from the Magee-Womens Obstetric Maternal and Infant data, and 240 pregnancies in a separate dataset of high-risk pregnancies...
December 1, 2017: Epidemiology
Richard F MacLehose, Lisa M Bodnar, Craig Meyer, Haitao Chu, Timothy L Lash
BACKGROUND: Validation data are used to estimate the extent of misclassification in epidemiologic studies. In the Penn MOMS cohort, prepregnancy BMI is subject to misclassification and validation data are available to estimate the extent of misclassification. We use these data to estimate the association between maternal prepregnancy body mass index and early preterm (<32 weeks) birth using a semi-Bayes hierarchical model allowing for more flexible adjustment for misclassification...
November 18, 2017: Epidemiology
Mohammad Ehsanul Karim, Menglan Pang, Robert W Platt
The use of retrospective healthcare claims datasets is frequently criticized for the lack of complete information on potential confounders. Utilizing patient's health status-related information from claims datasets as surrogates or proxies for mismeasured and unobserved confounders, the high-dimensional propensity score algorithm enables us to reduce bias. Using a previously published cohort study of post-myocardial infarction statin use (1998 - 2012), we compare the performance of the algorithm with a number of popular machine learning approaches for confounder selection in high-dimensional covariate spaces: random forest, least absolute shrinkage and selection operator, and elastic net...
November 18, 2017: Epidemiology
Andrea V Margulis, Joan Fortuny, James A Kaye, Brian Calingaert, Maria Reynolds, Estel Plana, Lisa J McQuay, Willem Jan Atsma, Billy Franks, Stefan de Vogel, Susana Perez-Gutthann, Alejandro Arana
BACKGROUND: In the United Kingdom, hospital or cancer registry data can be linked to electronic medical records for a subset of general practices and years. METHODS: We used Clinical Practice Research Datalink data (2004-2012) from patients treated for overactive bladder. We electronically identified provisional cases of 10 common cancers in General Practitioner Online Database data and validated them by medical profile review. In practices with linkage to Hospital Episodes Statistics and National Cancer Data Repository (2004-2010), we validated provisional cancer cases against these data sources...
November 9, 2017: Epidemiology
Fanny Kilpi, Pekka Martikainen, Hanna Konttinen, Karri Silventoinen, Jenny Torssander, Ichiro Kawachi
BACKGROUND: Education is believed to have positive spillover effects across network connections. Partner's education may be an important resource preventing the incidence of disease and helping patients cope with illness. We examined how partner's education predicted myocardial infarction (MI) incidence and survival net of own education and other socioeconomic resources in Finland. METHODS: A sample of adults aged 40-69 at baseline in Finland in 1990 was followed up for MI incidence and mortality during the period 1991-2007 (n=354,100)...
November 9, 2017: Epidemiology
G David Batty, Paola Zaninotto
No abstract text is available yet for this article.
November 9, 2017: Epidemiology
Neal D Goldstein
No abstract text is available yet for this article.
November 6, 2017: Epidemiology
Linn Håkonsen Arendt, Morten Søndergaard Lindhard, Tine Brink Henriksen, Jørn Olsen, Sven Cnattingius, Gunnar Petersson, Erik Thorlund Parner, Cecilia Høst Ramlau-Hansen
BACKGROUND: Diabetes in pregnancy has been associated with an increased risk of congenital malformations overall, but studies on genital anomalies in boys are conflicting and possible causal mechanisms are not well understood. Previous studies have mainly assessed pre-gestational and gestational diabetes in combination. Yet considering the vulnerable time windows for the genital anomalies, associations could well differ between types of diabetes and between the two genital anomalies and we therefore aimed to study this further...
November 6, 2017: Epidemiology
Lara S Lemon, Steve N Caritis, Raman Venkataramanan, Robert W Platt, Lisa M Bodnar
BACKGROUND: Our objective was to estimate the association between methadone and neonatal abstinence syndrome compared with buprenorphine using a probabilistic bias analysis to account for unmeasured confounding by severity of addiction. METHODS: We used a cohort of live-born infants exposed in utero to methadone or buprenorphine for maternal opioid maintenance therapy at Magee-Womens Hospital in Pittsburgh, PA from 2013-2015 (n=716). We determined exposure and outcome status using pharmacy billing claims...
November 6, 2017: Epidemiology
Corwin M Zigler, Christine Choirat, Francesca Dominici
BACKGROUND: Despite dramatic air quality improvement in the United States over the past decades, recent years have brought renewed scrutiny and uncertainty surrounding the effectiveness of specific regulatory programs for continuing to improve air quality and public health outcomes. METHODS: We employ causal inference methods and a spatial hierarchical regression model to characterize the extent to which a designation of "nonattainment" with the 1997 National Ambient Air Quality Standard for ambient fine particulate matter (PM2...
October 31, 2017: Epidemiology
Maarten van Wijhe, Scott A McDonald, Hester E de Melker, Maarten J Postma, Jacco Wallinga
BACKGROUND: There are few estimates of the effectiveness of long-standing vaccination programs in developed countries. To fill this gap, we investigate the direct and indirect effectiveness of childhood vaccination programs on mortality at the population level in the Netherlands. METHODS: We focused on three communicable infectious diseases, diphtheria, pertussis, and poliomyelitis, for which we expect both direct and indirect effects. As a negative control, we used tetanus, a non-communicable infectious disease for which only direct effects are anticipated...
October 30, 2017: Epidemiology
Sandie Ha, Danping Liu, Yeyi Zhu, Seth Sherman, Pauline Mendola
BACKGROUND: Extreme ambient temperatures have been linked to preterm birth. Preterm premature rupture of membranes is a common precursor to preterm birth but is rarely studied in relation to temperature. METHODS: We linked 15 381 singleton pregnancies with premature rupture of membranes from a nationwide US obstetrics cohort (2002-2008) to local temperature. Case-crossover analyses compared daily temperature during the week preceding delivery and the day of delivery to two control periods, before and after the case period...
October 30, 2017: Epidemiology
Loes Soetens, Don Klinkenberg, Corien Swaan, Susan Hahné, Jacco Wallinga
Contact tracing can provide accurate information on relevant parameters of an ongoing emerging infectious disease outbreak. This is crucial to investigators seeking to control such an outbreak. However, crude contact tracing data are difficult to interpret and methods for analyzing these data are scarce. We present a method to estimate and visualize key outbreak parameters from contact tracing information in real time by taking into account data censoring.Exposure type-specific attack rates and the reproduction number R(t) are estimated from contact tracing data by using maximum likelihood estimation to account for censored data...
October 30, 2017: Epidemiology
Jonathan S Schildcrout, Enrique F Schisterman, Melinda C Aldrich, Paul J Rathouz
BACKGROUND: Epidemiologists have long used case-control and related study designs to enhance variability of response and information available to estimate exposure-disease associations. Less has been done for longitudinal data. METHODS: We discuss an epidemiological study design and analysis approach for longitudinal binary response data. We seek to gain statistical efficiency by over-sampling relatively informative subjects for inclusion into the sample. In this methodological demonstration, we develop this concept by sampling repeatedly from an existing cohort study to estimate the relationship of chronic obstructive pulmonary disease to past-year smoking in a panel of baseline smokers...
October 27, 2017: Epidemiology
Kara E Rudolph, Nicole M Schmidt, M Maria Glymour, Rebecca Crowder, Jessica Galin, Jennifer Ahern, Theresa L Osypuk
BACKGROUND: The Moving to Opportunity (MTO) experiment manipulated neighborhood context by randomly assigning housing vouchers to volunteers living in public housing to use to move to lower poverty neighborhoods in five US cities. This random assignment overcomes confounding limitations that challenge other neighborhood studies. However, differences in MTO's effects across the five cities have been largely ignored. Such differences could be due to population composition (e.g., differences in the racial/ethnic distribution) and/or to context (e...
October 25, 2017: Epidemiology
Timothy L Lash, Enrique F Schisterman
No abstract text is available yet for this article.
October 24, 2017: Epidemiology
Marie C D Stoner, Stephen R Cole, Joan Price, Jennifer Winston, Jeff S A Stringer
BACKGROUND: Women who initiate antiretroviral therapy (ART) during pregnancy are reported to have lower risk of preterm birth compared to those who enter pregnancy care already receiving ART. We hypothesize this association can be largely attributed to selection bias. METHODS: We simulated a cohort of 1000 preconceptional, HIV-infected women, where half were randomly allocated to receive immediate ART and half to delay ART until their presentation for pregnancy care...
October 16, 2017: Epidemiology
Catherine R Lesko, Ashley L Buchanan, Daniel Westreich, Jessie K Edwards, Michael G Hudgens, Stephen R Cole
No abstract text is available yet for this article.
October 11, 2017: Epidemiology
Ian Shrier, Robert W Platt, Russell J Steele, Mireille Schnitzer
The intention-to-treat analysis evaluates the causal effect of treatment assignment in a randomized controlled trial; however, participants do not always adhere to assigned treatment and the intention to treat effect may differ from the effect of treatment receipt. Although more recent adherence-based methods assess a well-defined causal effect of receiving treatment, adherence is assumed to be dichotomized as all or none. This approach can lack precision in the real world because adherence is a complex and heterogeneous phenomenon...
October 11, 2017: Epidemiology
Timothy L Lash, Jay S Kaufman, Miguel A Hernán
No abstract text is available yet for this article.
October 11, 2017: Epidemiology
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