The traits that show a genetic correlation with alcohol consumption may correlate because of shared genetic effects on both traits or because of causal pathways between traits. In addition, genetic confounding may influence the correlations. A genetic correlation between smoking and alcohol consumption was identified in this study. As smoking also influences triglyceride levels68 this may be an indirect cause of the negative genetic correlation between alcohol consumption and triglyceride levels. Future studies should use Mendelian randomization analyses with the genetic variants identified in this study to probe causal relationships between alcohol use and health traits. Assortative mating may also influence the genetic correlations identified in this study. Alcohol consumption and nicotine use have been shown to be factors for nonrandom mating,69 and it is unclear what effect, if any, this would have on the genetic correlations presented in this study.
