Association of ankyrin repeats & kinase domain containing 1 (ANKK1) gene polymorphism with co-morbid alcohol & nicotine dependence: A pilot study from a tertiary care treatment centre in north India

BACKGROUND & OBJECTIVES: The frequently encountered co-morbidity of alcohol dependence (AD) with nicotine dependence (ND) increases the risk for various diseases. Ankyrin repeats and kinase domain containing 1 (ANKK1) gene polymorphism is reported to be associated with both ND and AD. This study was undertaken to investigate the possible association of alcohol and tobacco use variables with ANKK1 polymorphism in co-morbid alcohol- and nicotine-dependent treatment seekers visiting a tertiary care centre in north India. METHODS: Seventy nine male participants (18-65 yr old) fulfilling diagnostic criteria for ND and AD were included in the study. The socio-demographic data, along with alcohol and tobacco use profile, was recorded and ANKK1 profiling was carried out. Both the allele groups, A1 and A2, were compared with respect to demographic and substance dependence profile. Univariate binary logistic regression analysis was performed to determine the risk of high nicotine and alcohol consumption with genotype. RESULTS: The A1 carrier group (n=33) reported a significantly higher amount of alcohol and tobacco consumed per day. The scores on parameters of ND were found to be significantly higher in this group. The logistic regression analysis revealed that participants with A1 genotype were 2.5 times more likely to report higher amount of alcohol and nicotine consumption than A2 carriers. INTERPRETATION & CONCLUSIONS: The study provides an indication for the association of ANKK1 polymorphism in the form of higher substance consumption among alcohol dependent smokers, who are A1 carriers and thus may require higher attention of the treatment provider.