Another analysis investigated the association of alleles of another type of ADH, ADH1B, with alcohol dependence, drinking history, and liver function in Indo- and Afro-Trinidadians (Ehlers et al. 2007). That study determined the frequencies of two alleles, ADH1B*2 and ADH1B*3. The ADH1B*2 allele was found only in three Indo-Trinidadian participants (one alcoholic and two control subjects). However, 41 percent of the Afro-Trinidadian participants had at least one ADH1B*3 allele, and three Afro-Trinidadian participants were homozygous for the allele. Only one Indo-Trinidadian participant had at least one ADH1B*3 allele. Furthermore, people with at least one ADH1B*3 allele were significantly less likely to be alcohol dependent and had lower alcohol consumption levels compared with people without the allele. Among those participants who were alcohol dependent, ADH1B*3 was associated with significantly higher levels of the liver enzyme aspartate aminotransferase, which can be indicative of alcohol-induced liver disease. These analyses suggest that in this sample of Trinidadians, the ADH1B*3 allele has a protective effect against development of alcoholism; however, in people who do become alcohol dependent, the allele is associated with an enhanced risk for liver disease (Ehlers et al. 2007).
