The effect of TTC12-rs10502172[G] on smoking at age 31 was mainly indirect and mediated via its effect on smoking at 14 and novelty seeking. In contrast, the effect of CHRNA3-rs1051730[A] on smoking in adulthood was mainly direct and not mediated by smoking in adolescence or novelty seeking. Low socio-economic status and unmarried status during pregnancy were associated with maternal smoking, which in turn was positively associated with smoking behaviors in the offspring both at age 14 and 31. Low socio-economic status was independently associated with increased smoking behavior in the offspring both in adolescence and adulthood. High novelty seeking was associated with increased smoking behavior at both 14 and 31 years. Men as compared to women were at increased risk of smoking at 31 but not at 14 years.
