Study sheds light on the genetics of stopping smoking

The effectiveness of a common drug to quit smoking could be down to people’s genes, according to a study from the University of Leicester (United Kingdom).

Varenicline is widely recognised as the most effective medication for helping people stop smoking, but unfortunately it does not work for everyone.

Researchers from Leicester have uncovered important insights into how people’s DNA affects their response to the drug, which will soon be available to smokers through the UK’s National Health Service (NHS).

Varenicline works by targeting specific receptors in the brain to block the rewarding effects of smoking and reduce cravings.

An international team of researchers developed a method to use electronic health records to identify people who successfully stopped smoking with varenicline and those who did not.

The method was applied to the health records of people in Leicestershire and Rutland, in the Midlands, UK, who are part of the EXCEED (Extended Cohort for E-health, Environment and DNA) study. The method was also implemented in other national and international cohort studies, which have also collected genetic data.

In the largest study of its kind to date, the research team performed a genetic analysis to investigate whether differences in the genetic code of individuals could explain why varenicline treatment success varies.

The study, published in Nicotine and Tobacco Research, uncovered individual genetic variants (small differences in the DNA sequence) linked to stopping smoking using varenicline. The identified genetic variants highlight the involvement of genes in regulating gene activity and in the function of hair-like extensions of cells, called cilia.

The branded version of varenicline, Champix, has been unavailable since 2021 due to a manufacturing impurity. However, at the end of 2024, it was announced that that a generic version of varenicline has been approved and is in the process of being reintroduced into the NHS.

Dr Kayesha Coley, the study’s lead researcher, said: “Our study is the first to scan the entire genome to look for genes linked to successfully stopping smoking using varenicline. The genes give us some useful insights into the diverse biological processes at play, but the next step is to confirm our findings with even larger studies. Now that varenicline is being rolled out again in the UK, we have exciting opportunities for future research.”

Dr Catherine John, Scientific Director of EXCEED, said: “Smoking is still one of the biggest killers in the UK and worldwide, and over half of smokers say they want to quit. Research into how to support people to stop smoking is essential, and studies like EXCEED play an important role in this. We would like to thank all the participants in EXCEED and the other studies that contributed to this research.”

The research team emphasised the importance of continued studies in this area to further investigate how genetics influences the success of varenicline and further enhance biological understanding.

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