It is also important to note phenotypic differences between this study and previous ones. Most previous GWAS studies have focused on lifetime measures related to alcohol use, such as alcohol dependence, while others have used a single time measure of maximum drinks in a 24-hour period. By comparison, ours focused on two measures of alcohol consumption over the past year (drinker status and drinks/week). All of these traits have been shown to be highly correlated genetically, but there are also differences. For example, alcohol use disorders (abuse or dependence) are reflective of lifetime exposure – but also other potential factors not directly related to consumption. That could explain why some genetic findings associated with alcohol use disorders might not be found associated with measures of alcohol consumption. However, our findings have generally confirmed prior associations, suggesting that many of the previously reported genetic variants for alcohol use disorders are directly related to consumption, measured either over a short or long time period.
