in the 3′UTR of CHRNB4 gene, rs1948, has been linked to early age of initiation for tobacco use in an ethnically diverse young adult cohort [32]. They also found that a variant, rs11634351 that is in low LD with rs1948 (r2 = 0.24) had significant association with age at first drink [32]. In current study we found that rs11634351 is associated with AAO of daily smoking and is in complete LD with rs1996371 (Figure 2). High comorbidity among smoking and drinking behaviors might explain this possible overlap [33].
