locus were used) [21,22]. This confirms the results of Mendelian randomization analyses of alcohol consumption and blood pressure conducted prior to these later GWAS [23]. In other words, alcohol consumption causes high blood pressure, and this is detected in GWAS of high blood pressure, but only when tested in populations in which the variants associated with alcohol consumption are sufficiently common. This provides strong evidence that the identification of this locus in the GWAS is due to a causal effect of alcohol consumption rather than being due to shared genetic aetiology or to pleiotropy. Similarly, ALDH2 has emerged in GWAS of esophageal cancer in East Asian samples [24], confirming earlier Mendelian randomization analyses [25].
