title: Estimation of the relative excess risk due to interaction and associated confidence bounds.
abstract: The relative excess risk due to interaction (RERI) provides a useful metric of departure from additivity of effects on a relative risk scale. In this paper, the authors show that RERI is identical to the product term in a linear odds ratio or a linear relative risk model. SAS and STATA codes are provided for fitting a linear odds ratio model that directly parameterizes RERI. In addition, this paper presents a method for obtaining likelihood-based 95% confidence bound estimates for RERI. The authors show that likelihood-based confidence intervals may differ substantially from the asymptotic confidence interval estimates advocated by previous authors. The approach presented in this paper should facilitate estimation of RERI and associated likelihood-based confidence bounds, by using standard statistical packages.
authors.affiliation: Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC 27599, USA. david.richardson@unc.edu
authors.forename: David B
authors.initials: DB
authors.lastname: Richardson
authors.forename: Jay S
authors.initials: JS
authors.lastname: Kaufman
mesh_terms: D016001:Confidence Intervals; D004812:Epidemiologic Methods; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D016017:Odds Ratio; D012107:Research Design; D012306:Risk