Genetic polymorphism of the adenosine A2A receptor is associated with habitual caffeine consumption

Abstract

Caffeine is the most widely consumed stimulant in the world with an estimated 80–90% of adults reporting regular consumption of caffeine-containing beverages and foods (1). Caffeine intakes vary widely from country to country and from person to person (2, 3). The pleasurable and reinforcing effects of caffeine have led to some concern that it is a potential drug of dependence (1, 4, 5). However, some persons experience anxiety, tachycardia, nervousness. or other adverse effects with low-to-moderate intakes of caffeine (4). These differences in response to caffeine may explain some of the variability in caffeine intake within a population (1, 6, 7). Although demographic, psychosocial, health-related, and environmental factors such as smoking have been linked to habitual caffeine consumption (8–11), there is some evidence that genetic factors are also important (12–15). Twin studies report heritability estimates of up to 77% for caffeine use, toxicity, tolerance, and withdrawal symptoms(12–15), but the specific genes involved are not yet identified.