It is important to study the genetics of nicotine dependence in diverse populations. Differences in allele frequencies and genetic architecture between populations can help narrow association signals to biologically causal variants. Also, there can be important phenotypic differences between populations. Current smoking prevalence is similar in European-Americans and African-Americans (Centers for Disease Control and Prevention, 2008). Nicotine dependence is common in both groups, with evidence of slightly lower levels of dependence in African-Americans by standard measures currently in use (Breslau et al., 2001, Substance Abuse and Mental Health Services Administration, 2007). Smoking cessation rates, however, are lower in African-Americans compared to European-Americans (Breslau et al., 2001, Covey et al., 2008). Furthermore there is evidence that African-Americans have a higher risk of dependence at lower cigarettes-per-day levels compared to European-Americans (Luo et al., 2008). Also important are the disparities in health consequences from smoking: African-Americans have higher lung cancer incidence and mortality than European-Americans (Haiman et al., 2006, Ries et al., 2008). An understanding of the genetic loci involved, and their effects and allele frequencies in diverse populations, can provide important clues to the risk of developing nicotine dependence across all populations.
