Alaska Native and American Indian (ANAI) people have a smoking prevalence of 23%. Nicotine metabolite ratio (NMR) and genetic testing may enable tailored selection of tobacco cessation medication. The purpose of this study was to evaluate the relative contributions of NMR, cessation medication, demographics, and tobacco use history to cessation.
Participants were recruited into an observational cohort study consisting of a baseline visit prior to their quit date and 6 week follow-up. Demographic and tobacco use surveys and blood, urine, and breath samples were collected at each visit. Electronic health records were queried for cessation medications. NMR was categorized into slow or normal nicotine metabolism phenotypes (<0.31 and ≥0.31 respectively). The main outcome was cessation at 6 weeks. Analyses consisted of descriptive statistics, medication/phenotype concordance, and estimates of relative risk of quitting.
We enrolled 151 ANAI adults who smoked cigarettes daily. Two-thirds had normal nicotine metabolism phenotype. Retrospective medication/phenotype concordance was 39%. The overall quit rate was 25%. No demographic factors or tobacco use history were associated with quit success. Varenicline and bupropion increased the likelihood of quitting (RR=2.93 [1.42, 6.03] and RR=2.52 [1.12, 5.64] respectively) compared to nicotine replacement therapy. Non-optimal medication/phenotype concordance decreased likelihood of quit success (RR=0.44 [0.22, 0.91]) compared to optimal concordance.
This exploratory study found associations between quit success and tobacco cessation medication as well as medication/phenotype concordance. Additional research is needed to assess use of NMR for treatment selection among ANAI people.
These results broadly support additional community-engaged research to improve medication/phenotype concordance in tribal health settings. Such interventional research holds promise to improve expectations, quit success, and health outcomes amongst individuals attempting to quit smoking.