The EA and AA participants in the NicW GWAS are described in Table 1. The Yale–Penn-1 and Yale–Penn-2 subjects were recruited at multiple Eastern US sites for genetic studies of drug and alcohol dependence, as described elsewhere.23–25 These subjects were phenotyped using the polydiagnostic Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA).30 Yale-Penn study participants provided written informed consent prior to their participation and the institutional review board at each participating site approved the studies. The National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism issued Certificates of Confidentiality to protect Yale-Penn study participants. The GWAS also included data from the Study of Addiction: Genetics and Environment (SAGE),26 obtained via the database of Genotypes and Phenotypes (accession: phs000092.v1.p1). The SAGE dataset includes subjects from COGA (the Collaborative Study on the Genetics of Alcoholism),28 FSCD (the Family Study of Cocaine Dependence) 27 and COGEND (the Collaborative Genetic Study of Nicotine Dependence).26 Only subjects who smoked at least 100 cigarettes in their lifetime were included in the GWAS.
