alcohol challenge study found Asians with two ADH1B*2 alleles had greater objective (e.g., vomiting) and subjective (e.g., feeling less “great”) responses to a moderate dose of alcohol than individuals with one ADH1B*2 allele, but that this occurred only in ALDH2 heterozygotes (Cook et al., 2005). Our finding is also consistent with the associations of ALDH2 and ADH1B with risk for alcohol dependence, where the protective effects of these genes are stronger for both variants alleles in conjunction (Chen et al. 1999; Luczak et al., 2006). Thus, the effects of ADH1B*2 may be stronger (and thus emerge as significant in statistical analyses) when the allele is possessed along with other genetic variants (e.g., ALDH2 in a gene-gene interaction) or as has been shown in previous reports when in association with certain alcohol behaviors (e.g., heavier drinking in a gene-environment interaction; Higuchi et al., 1996).
