In sum, this is the first genetic study aimed at investigating a potential association of the variants of the CHRNA5/A3/B4 cluster with ND in a sample of AA smokers. Although our results reveal a relatively weak association of the cluster with ND, we did find significant interaction among variants of the three subunit genes in affecting ND. As for the EA population, we did not identify significant interactions of variants in this cluster, although we found a nominal association of the cluster with ND. The small size of our EA sample may have contributed, in part, to the weak association.
