Nicotine dependence linked to DNA

Certain gene variants are more common in people who smoke. Image: Vladimir Tronin/Shutterstock Your DNA may play a significant role in determining whether or not you end up a smoker – and how easy you find it to kick the habit. Many large studies have identified particular gene variants that are more common in smokers than other people, suggesting they play a role in nicotine dependence. Now an international team of researchers have used these genetic clues develop a ‘genetic risk profile’, and to see how accurate it is, they have road-tested it on the on a well-known sample of Kiwis: the Dunedin Birth Cohort. Researchers analysed data from the long-term study of 1,000 New Zealanders to identify whether individuals at high genetic risk got hooked on cigarettes more quickly as teens and whether, as adults, they had a harder time quitting. The results, published in JAMA Psychiatry, showed that a person’s genetic risk profile did not predict whether he or she would try cigarettes. But for those who did try cigarettes, having a high-risk genetic profile predicted increased likelihood of heavy smoking and nicotine dependence. This link was most apparent for teenagers. Among teens who tried cigarettes, those with a high-risk genetic profile were 24 percent more likely to become daily smokers by age 15 and 43 percent more likely to become pack-a-day smokers by age 18. As adults, those with high-risk genetic profiles were 22 percent more likely to fail in their attempts at quitting. “The effects of genetic risk seem to be limited to people who start smoking as teens,” said author Daniel Belsky, a post-doctoral research fellow at Duke University. “This suggests there may be something special about nicotine exposure in the adolescent brain, with respect to these genetic variants.” The authors noted that their genetic risk profile isn’t yet accurate enough to be used for targeted interventions to prevent at-risk teens smoking, but it does highlight the critical adolescent period in addiction development. “Public health policies that make it harder for teens to become regular smokers should continue to be a focus in antismoking efforts,” Belsky said. Editor's Note: Original news release can be found here.