Genetic ancestry as an effect modifier of naltrexone in smoking cessation among African Americans: An analysis of a randomized controlled trial

Adam Bress, Rick Kittles, Coady Wing, Stanley E. Hooker, Andrea King

Research output: Contribution to journalArticle

8 Scopus citations


Objectives To determine whether there were differential quit rates between African Americans (AA) and European Americans with the experimental treatment naltrexone, and examine the role of genetic ancestry on these outcomes among AAs. Methods: Data from a previous randomized trial of 315 smokers to naltrexone versus placebo were reanalyzed using West African (WA) genetic ancestry to define subpopulations. Logistic regression models were used to estimate treatment effects on early and end of treatment quit rates, by race and WA ancestry. Results: Among European Americans (n= 136), naltrexone significantly increased quit rates at 4 weeks (62 vs. 43%, P = 0.03) with directional, but not statistically significant effects at 12 weeks (30 vs. 18%, P=0.12). In contrast, among the AAs (n =95), quit rates did not differ between naltrexone and placebo groups at either interval (4 weeks: 43 vs. 32%, P =0.27; 12 weeks: 22 vs. 18%, P= 0.60). A median split was conducted in AAs for WA ancestry. Among AAs with low WA ancestry, quit rates were significantly higher with naltrexone compared with placebo (60 vs. 27%, P =0.03). There was no advantage in quit rates with naltrexone for the high WA ancestry group. Conclusion: Naltrexone efficacy for smoking cessation varies across AA individuals with different levels of WA ancestry. These results suggest that genetic background may partially explain racial differences in drug response.

Original languageEnglish (US)
Pages (from-to)305-312
Number of pages8
JournalPharmacogenetics and Genomics
Issue number6
StatePublished - May 15 2015



  • African Americans
  • Ancestry
  • Naltrexone
  • Pharmacogenomics
  • Smoking cessation

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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