Smoking, race, ancestry and prospective abstinence

Abstract Background Factors influencing cessation include biopsychosocial characteristics, treatments and responses to treatment. The first cessation trial designed to assess cessation disparities between African American and White cigarette smokers demonstrated that socioeconomic, treatment, psychosocial and smoking characteristics explained cessation disparities. Ongoing translational efforts in precision cessation treatment grounded in genetically informed biomarkers have identified cessation differences by genotype, metabolism, ancestry and treatment. Methods In planned analyses, we evaluated six smoking-related measures, demographic and socioeconomic covariates, and prospective abstinence (7-day point prevalence at 12 weeks with bupropion, nicotine replacement and counseling treatments). We assessed concurrent and predictive validity in two covariate models differing by inclusion of Office of Management and Budget (OMB) race/ethnicity or genomic ancestry. Results We studied Pharmacogenetic Study participants (N=456, mean age 49.5 years, 41.5% female, 7.4% African American, 9.4% Multiracial, 6.5% Other, and 6.7% Hispanic). Cigarettes per day (OR=0.95, P <.001), Fagerström score (OR=0.89, P <=.014), Time-To-First-Cigarette (OR=0.75, P <=.005) and predicted urinary nicotine metabolite ratio (OR=0.57, P <=.039) were associated with abstinence. OMB African American race (ORs from 0.31 and 0.35, p-values <=.007) and African genomic ancestry (ORs from 0.21 and 0.26, p-values <=.004) were associated in all abstinence models. Conclusions Four smoking-related measures exhibited association with abstinence, including predicted nicotine metabolism based on a novel genomic model. African genomic ancestry was independently associated with reduced abstinence. Treatment research that includes social, psychological, treatment and biological factors is needed to reduce cessation disparities. Implications This is the first application of a statistical learning model of the urinary nicotine metabolite ratio to cessation. Results are concordant with biochemical and genetic models of the plasma nicotine metabolite ratio in multiethnic samples. The urinary ratio exhibits the largest standardized effect size of four smoking-related measures associated with cessation (time-to-first cigarette, total Fagerström score and cigarettes per day were the others). The social construct of African American race and genomic African ancestry are significant covariates in all cessation models. Results point to social and biological mechanisms requiring investigation in larger samples to understand and reduce cessation health disparities.