phenocov_mvmr: phenocov_mvmr

In WSpiller/MRPracticals: An R Package illustrating features of MR Base and RadialMR

Description

Uses an external phenotypic covariance matrix and summary data to estimate covariance matrices for estimated effects of individual genetic variants on each exposure. The function returns a number of covariance matrices equal to the number of SNPs, where SNP and row numbers reference ordered exposures.

Usage

phenocov_mvmr(Pcov, seBXGs)

Arguments

Pcov	A phenotypic matrix using exposures, constructed using individual level exposure data. Columns should be ordered by exposure so as to match format_mvmr.
seBXGs	A matrix containing standard errors corresponding in relation to the gene-exposure association for each SNP.

Value

A list of covariance matrices with respect to each genetic variant, retaining the ordering in Gs

Author(s)

Wes Spiller; Eleanor Sanderson; Jack Bowden.

References

Sanderson, E., et al., An examination of multivariable Mendelian randomization in the single-sample and two-sample summary data settings. International Journal of Epidemiology, 2018. [Internet]. 2018;dyy262. Available from: https://dx.doi.org/10.1093/ije/dyy262

Examples

phenocov_mvmr(Pcov,summarydata[,c(3,4)])

WSpiller/MRPracticals documentation built on April 25, 2020, 10:52 a.m.