Importantly, for both rs1451240 and rs6265, when smoking initiation and FTND were included as covariates, the associations with the cannabis measures were no longer statistically significant. While this might imply that the associations observed with cannabis involvement are not independent of the associations between these SNPs and tobacco-related outcomes, it is worth noting that the point estimates for and variance explained by each SNP remained relatively unchanged even after accounting for tobacco smoking. Therefore, it is possible that power to detect their specific/independent effects on cannabis involvement was attenuated in this sample that is enriched for nicotine dependence.
