We did not find any significant loci in the much smaller African or East Asian ancestry analyses, due to the lack of power. The lack of diversity in genetic data is unfortunate as nicotine dependence and tobacco use disorder are leading contributors to mortality in worldwide populations2,42. A related limitation was our inability to conduct sex- and birth cohort-stratified analyses; rates of tobacco use vary markedly according to both sex and birth cohort, which may in turn modify the extent to which genetic liability influences risk for DSM-NicDep. Amassing more genetic datasets with DSM-derived nicotine dependence would enable such valuable analyses.
