Measuring alcohol consumption for genomic meta-analyses of alcohol intake: Opportunities and challenges

Whereas moderate drinking may have health benefits, excessive alco-hol consumption causes many important acute and chronic diseases and is the third leading contributor to preventable death in the United States. Twin studies suggest that alcohol-consumption patterns are her-itable (50%); however, multiple genetic variants of modest effect size are likely to contribute to this heritable variation. Genome-wide asso-ciation studies provide a tool for discovering genetic loci that contrib-ute to variations in alcohol consumption. Opportunities exist to identify susceptibility loci with modest effect by meta-analyzing to-gether multiple studies. However, existing studies assessed many dif-ferent aspects of alcohol use, such as typical compared with heavy drinking, and these different assessments can be difficult to reconcile. In addition, many studies lack the ability to distinguish between life-time and recent abstention or to assess the pattern of drinking during the week, and a variety of such concerns surround the appropriateness of developing a common summary measure of alcohol intake. Com-bining such measures of alcohol intake can cause heterogeneity and exposure misclassification, cause a reduction in power, and affect the magnitude of genetic association signals. In this review, we discuss the challenges associated with harmonizing alcohol-consumption data from studies with widely different assessment instruments, with a par-ticular focus on large-scale genetic studies. Am J Clin Nutr 2012;95:539–47