title: Estimating average attributable fractions with confidence intervals for cohort and case-control studies.
abstract: Chronic diseases tend to depend on a large number of risk factors, both environmental and genetic. Average attributable fractions were introduced by Eide and Gefeller as a way of partitioning overall disease burden into contributions from individual risk factors; this may be useful in deciding which risk factors to target in disease interventions. Here, we introduce new estimation methods for average attributable fractions that are appropriate for both case-control designs and prospective studies. Confidence intervals, derived using Monte Carlo simulation, are also described. Finally, we introduce a novel approximation for the sample average attributable fraction that will ensure a computationally tractable approach when the number of risk factors is large. An R package, [Formula: see text], implementing the methods described in this manuscript can be downloaded from the CRAN repository.
authors.affiliation: 1 HRB Clinical Research Facility, National University of Ireland Galway, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Ferguson
authors.affiliation: 1 HRB Clinical Research Facility, National University of Ireland Galway, Ireland.
authors.forename: Alberto
authors.initials: A
authors.lastname: Alvarez-Iglesias
authors.affiliation: 1 HRB Clinical Research Facility, National University of Ireland Galway, Ireland.|2 School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Newell
authors.affiliation: 2 School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Hinde
authors.affiliation: 1 HRB Clinical Research Facility, National University of Ireland Galway, Ireland.
authors.forename: Martin
authors.initials: M
authors.lastname: O'Donnell
mesh_terms: D035843:Biomedical Research / Q000706:statistics & numerical data; D016022:Case-Control Studies; D002908:Chronic Disease; D016001:Confidence Intervals; D006801:Humans; D009010:Monte Carlo Method; D011446:Prospective Studies; D018570:Risk Assessment / Q000706:statistics & numerical data; D012307:Risk Factors
keywords: Epidemiology; Monte Carlo confidence interval; attributable fraction; permutations; weighted likelihood