Credible Mendelian randomization studies: approaches for evaluating the instrumental variable assumptions.

ABSTRACT: As with other instrumental variable (IV) analyses, Mendelian randomization (MR) studies rest on strong assumptions. These assumptions are not routinely systematically evaluated in MR applications, although such evaluation could add to the credibility of MR analyses. In this article, the authors present several methods that are useful for evaluating the validity of an MR study. They apply these methods to a recent MR study that used fat mass and obesity-associated (FTO) genotype as an IV to estimate the effect of obesity on mental disorder. These approaches to evaluating assumptions for valid IV analyses are not fail-safe, in that there are situations where the approaches might either fail to identify a biased IV or inappropriately suggest that a valid IV is biased. Therefore, the authors d

SUBMITTER: Glymour MM 

PROVIDER: S-EPMC3366596 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature