title: Genetic markers as instrumental variables.
abstract: The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists, statisticians, epidemiologists and social scientists. Although IV is commonly used in economics, the appropriate conditions for the use of genetic variants as instruments have not been well defined. The increasing availability of biomedical data, however, makes understanding of these conditions crucial to the successful use of genotypes as instruments. We combine the econometric IV literature with that from genetic epidemiology, and discuss the biological conditions and IV assumptions within the statistical potential outcomes framework. We review this in the context of two illustrative applications.
authors.affiliation: University of Bristol, Bristol, United Kingdom. Electronic address: S.vonHinke@bristol.ac.uk.
authors.forename: Stephanie
authors.initials: S
authors.lastname: von Hinke
authors.affiliation: University of Bristol, Bristol, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Davey Smith
authors.affiliation: University of Bristol, Bristol, United Kingdom.
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
authors.affiliation: University of Bristol, Bristol, United Kingdom; Imperial College London, London, United Kingdom.
authors.forename: Carol
authors.initials: C
authors.lastname: Propper
authors.affiliation: University of Bristol, Bristol, United Kingdom.
authors.forename: Frank
authors.initials: F
authors.lastname: Windmeijer
mesh_terms: D000465:Algorithms; D015982:Bias; D004739:England; D005819:Genetic Markers; D014644:Genetic Variation; D006801:Humans; D008137:Longitudinal Studies; D057182:Mendelian Randomization Analysis
chemical_list: D005819:Genetic Markers
keywords: ALSPAC; Genetic variants; Instrumental variables; Mendelian randomization; Potential outcomes