In a paper published online in advance in Translational Psychiatry, a team led by researchers at nonprofit institute SRI International shows in a GWAS meta-analysis that a non-coding SNP on chromosome 15q25.1 is associated with smoking quantity — as measured by cigarettes per day — in African Americans. In their paper, members of the Study of Tobacco in Minority Populations Genetics Consortium say that this variant "is present in the 5'-distal enhancer region of the CHRNA5 gene," and that additional, informative associations — at 15q25.1 within PSMA4, CHRNA5, and CHRNA3 — approached, but did not reach, genome-wide significance for smoking quantity. These additional SNPs "are associated with a second signal previously reported in studies in European ancestry populations," the team says.
Overall, the authors write, larger studies are needed to validate the suggestive loci "and further elucidate the contribution of genetic variation to disparities in cigarette consumption, SC [smoking cessation], and smoking-attributable disease between African Americans and European Americans."