Background: Waterpipe smoking is increasingly a worldwide phenomenon. Few studies have been conducted on the epidemiology of waterpipe smoking behavior and its genetic determinants. A polymorphism (TaqI) in the 3' untranslated region of the dopamine receptor gene (DRD2), later localized to the neighboring ANKK1 gene, has been previously linked to cigarette smoking. Since all tobacco products share the ability of stimulating the dopaminergic reward system, variation in the DRD2 genotype might be associated with waterpipe smoking addiction.
Aim: This study aims to explore genetic variations in DRD2 gene and waterpipe smoking, motives and addiction in Egyptian rural males.
Material and methods: The subjects (N=154) were selected from participants in a household smoking prevalence survey if they were adults, males, currently smoking waterpipe and not smoking cigarettes. Participants were interviewed about their smoking behaviors. Blood samples were genotyped by polymerase chain reaction (PCR). Subjects were subsequently classified as either the A1 (presence of at least one A1 allele) or A2 group (A2 homozygotes).
Results: The prevalence of A1 genotype was 34.4 % in current waterpipe users, and was associated with the maximum duration before smokers experienced craving to smoke: after adjusting for age of smoking initiation, smoking for addictive motives, and average daily tobacco consumption, the A1 carriers were more likely to experience craving within a shorter duration after abstinence (the first 24 hours) compared to subjects with A2/A2 genotype (Odds ratio [OR] 2.70, 95% confidence interval [CI]: 1.18 - 6.23). In addition, the frequent visitors of shisha cafes were more likely to be younger, heavy smokers and carriers of A1 allele (OR, 2.52, 95% CI: 1.06-6.02).
Conclusion and recommendations: This study revealed that the maximum duration before experiencing craving to smoke waterpipe and frequency of visiting cafés to smoke may be influenced by an inherited variations in the DRD2 genotype.