title: Assessment of systematic effects of methodological characteristics on candidate genetic associations.
abstract: Candidate genetic association studies have been found to have a low replication rate in the past. Here, we aimed to assess whether aspects of reported methodological characteristics in genetic association studies may be related to the magnitude of effects observed. An observational, literature-based investigation of 511 case-control studies of genetic association studies indexed in 2007, was undertaken. Meta-regression analyses were used to assess the relationship between 23 reported methodological characteristics and the magnitude of genetic associations. The 511 studies had been conducted in 52 countries and were published in 220 journals (median impact factor 5.1). The multivariate meta-regression model of methodological characteristics plus disease category accounted for 17.2 % of the between-study variance in the magnitude of the reported genetic associations. Our findings are consistent with the view that better conducted and better reported genetic association research may lead to less inflated results.
authors.affiliation: Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Badr
authors.initials: B
authors.lastname: Aljasir
authors.forename: John P A
authors.initials: JP
authors.lastname: Ioannidis
authors.forename: Alex
authors.initials: A
authors.lastname: Yurkiewich
authors.forename: David
authors.initials: D
authors.lastname: Moher
authors.forename: Julian P T
authors.initials: JP
authors.lastname: Higgins
authors.forename: Paul
authors.initials: P
authors.lastname: Arora
authors.forename: Julian
authors.initials: J
authors.lastname: Little
mesh_terms: D056726:Genetic Association Studies / Q000379:methods; D006801:Humans; D016017:Odds Ratio; D012044:Regression Analysis