Sample size and power calculations in Mendelian randomization with a single instrumental variable and a binary outcome.

ABSTRACT:

Background

Sample size calculations are an important tool for planning epidemiological studies. Large sample sizes are often required in Mendelian randomization investigations.

Methods and results

Resources are provided for investigators to perform sample size and power calculations for Mendelian randomization with a binary outcome. We initially provide formulae for the continuous outcome case, and then analogous formulae for the binary outcome case. The formulae are valid for a single instrumental variable, which may be a single genetic variant or an allele score comprising multiple variants. Graphs are provided to give the required sample size for 80% power for given values of the causal effect of the risk factor on the outcome and of the squared correlation between the ri

SUBMITTER: Burgess S 

PROVIDER: S-EPMC4052137 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature