ABSTRACT
Much of this book has been motivated and illustrated by data collected by the CRP CHD Genetics Collaboration [CCGC, 2008]. In this chapter, we analyse the entirety of the CCGC data to estimate the causal effect of C-reactive protein (CRP) on coronary heart disease (CHD) risk as an illustration of the Mendelian randomization approach, as well as several of the methodological issues highlighted in this book. We first give an overview of the complete dataset and address the validity of the genetic variants as instrumental variables (IVs) (Section 10.1). We then analyse a single study, exemplifying some features of the data (Section 10.2), before continuing to present an analysis of the full dataset (Section 10.3). We conclude this chapter with a discussion, including the interpretation of the results of this analysis (Section 10.4). A more detailed analysis of these data is available in a published paper [Burgess et al., 2012].
