Multiancestry Study of Gene-Lifestyle Interactions for Cardiovascular Traits in 610 475 Individuals From 124 Cohorts: Design and Rationale

Abstract

Background: Several consortia have pursued genome-wide association studies for identifying novel genetic loci for blood pressure, lipids, hypertension, etc. They demonstrated the power of collaborative research through meta-analysis of study-specific results.

Methods and results: The Gene-Lifestyle Interactions Working Group was formed to facilitate the first large, concerted, multiancestry study to systematically evaluate gene-lifestyle interactions. In stage 1, genome-wide interaction analysis is performed in 53 cohorts with a total of 149 684 individuals from multiple ancestries. In stage 2 involving an additional 71 cohorts with 460 791 individuals from multiple ancestries, focused analysis is performed for a subset of the most promising variants from stage 1. In all, the study involves up to 610 475 individuals. Current focus is on cardiovascular traits including blood pressure and lipids, and lifestyle factors including smoking, alcohol, education (as a surrogate for socioeconomic status), physical activity, psychosocial variables, and sleep. The total sample sizes vary among projects because of missing data. Large-scale gene-lifestyle or more generally gene-environment interaction (G×E) meta-analysis studies can be cumbersome and challenging. This article describes the design and some of the approaches pursued in the interaction projects.

Conclusions: The Gene-Lifestyle Interactions Working Group provides an excellent framework for understanding the lifestyle context of genetic effects and to identify novel trait loci through analysis of interactions. An important and novel feature of our study is that the gene-lifestyle interaction (G×E) results may improve our knowledge about the underlying mechanisms for novel and already known trait loci.

Keywords: blood pressure; genome-wide association study; life style; meta-analysis; molecular epidemiology.

Figure 1

Overall flow of analyses. Combined analysis leverages the full power of Stages 1 and 2. The traditional discovery and replication approach identifies additional loci missed by the combined approach. Both approaches can be used for maximizing discovery.

Figure 2

Sample sizes needed for 80% power using the 2 df joint test. Sample size (Y-axis) is plotted as a function of the percent variance explained by the interaction (R2GE; X-axis), for each of 4 different values of the percent variance explained by the genetic effect (R2G); that due to the lifestyle factor (R2E) is fixed at 0.1% (see the text).