and combined effects of common polymorphisms within CHRNA5-CHRNA3-CHRNB4 and TTC12-ANKK1-DRD2 gene-clusters on smoking behaviour during adolescence and mid-adulthood in a prospective general population based cohort including 4,762 Finns (Northern Finland 1966 Birth Cohort, NFBC 1966). We tested whether the genetic effects of these two loci on smoking changed moving from adolescence to mid-adulthood. Finally, we tested the joint effects of the most significantly associated loci within these two chromosome regions, namely CHRNA3-rs1051730 and TTC12-rs10502172, and other factors that have been previously associated with smoking in the NFBC 1966, such as maternal smoking(39), novelty seeking(40), and socio-economic status(41–43), and we attempted to construct an integrative, albeit incomplete, etiological model testing specific life-course pathways leading to smoking behavior.
