Objective: Two polymorphisms in the promoter region of the gene encoding cytosolic aldehyde dehydrogenase (ALDH1A1), ALDH1A1*2 and ALDH1A1*3, have recently been identified. The present study sought to determine whether an association exists between ALDH1A1 genotypes, alcohol dependence, drinking history, and liver function tests in the two major ethnic groups of Trinidad and Tobago (TT).
Method: The participants in this study were 137 alcohol dependents of either East Indian ancestry (Indo-TT) or African ancestry (Afro-TT) and 108 controls matched by age, gender, and ethnicity. A structured interview was used to gather information on demographics, psychiatric diagnoses, and personal drinking and drug use. A blood sample was obtained from each participant, and leukocyte DNA was extracted and used to genotype for the presence of the ALDH1A1 promoter polymorphisms. Serum levels of hepatic enzymes, as well as presence of HIV, hepatitis B surface antigen, and antihepatitis C virus antibody, were also determined.
Results: Twenty-four participants (10%) possessed the ALDH1A1*1/*2 genotype (frequency = .05), 4 were Afro-TT (2 alcohol dependents, 2 controls), and 20 were Indo-TT (18 alcohol dependents, 2 controls). Two participants (1 Indo-TT alcohol dependent, 1 Afro-TT alcohol dependent) had the ALDH1A1*2/*2 genotype. Four participants possessed ALDH1A1*3, all of whom were Afro-TT controls. Indo-TT participants with at least one ALDH1A1*2 allele were more likely to have a lifetime diagnosis of Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, alcohol dependence (p < .002). Indo-TT participants with ALDH1A1*2 also reported significantly higher levels of current alcohol consumption (p < .05). The small number of Afro-TT participants with atypical polymorphisms limits any conclusions on the possible impact on alcohol dependence in that population.
Conclusions: Results from this study suggest that ALDH1A1*2 may be associated with increased risk for the development of alcohol dependence in Indo-Trinidadians.