Diagnostics of Pleiotropy in Mendelian Randomization Studies: Global and Individual Tests for Direct Effects.

Diagnostics of Pleiotropy in Mendelian Randomization Studies: Global and Individual Tests for Direct Effects. Am J Epidemiol. 2018 Sep 05;: Authors: Dai JY, Peters U, Wang X, Kocarnik J, Chang-Claude J, Slattery ML, Chan A, Lemire M, Berndt SI, Casey G, Song M, Jenkins MA, Brenner H, Thrift AP, White E, Hsu L Abstract Diagnosing pleiotropy is critical for assessing the validity of Mendelian randomization (MR) analyses. The popular MR-Egger method evaluates whether there is evidence of bias-generating pleiotropy among a set of candidate genetic instrumental variables. In this article, we propose GLIDE, GLobal and Individual tests for Direct Effects, a statistical method to systematically evaluate pleiotropy among the set of genetic variants, e.g., single nucleotide polymorphisms (SNPs), used for MR. As a global test, simulation experiments suggest that GLIDE is nearly uniformly more powerful than the MR-Egger method. As a sensitivity analysis, GLIDE is capable of detecting outliers in individual variant-level pleiotropy, in order to obtain a refined set of genetic instrumental variables. We used GLIDE to analyze both body-mass index and height for risk of colorectal cancer in the Genetics and Epidemiology of Colorectal Cancer Consortium. Among the body mass index associated SNPs and the height associated SNPs, several individual variants showed evidence of pleiotropy. Removal of these potentially pleiotropic SNPs resulted in attenuati...
Source: Am J Epidemiol - Category: Epidemiology Authors: Tags: Am J Epidemiol Source Type: research