Genes Don’t Trigger Smoking Habits

Tobacco addiction genes influence heavy smoking and trouble quitting but not initiation

(RxWiki News) Having genes linked to a smoking addiction does not predict a future smoker. Keeping cigarettes away from minors and supporting adults in quitting is what matters.

A recent study followed a group of people for 38 years to compare their smoking habits with their genetic risk for a possible smoking addiction.

The results of the study showed that high-risk genes were more often present in teens that started smoking heavily before the age of 18 and who had a tougher time quitting in adulthood than in people without the high risk genes.

"Call 1-800-Quit-Now."

Daniel Belsky, PhD, a post-doctoral research fellow at the Center for the Study of Aging and Human Development at Duke University and the Duke Institute for Genome Sciences & Policy in Durham, NC, led an investigation into people with higher genetic risk for smoking addictions.

For the study, 1,037 men and women born between April 1972 and March 1973 in New Zealand were followed for 38 years. Each person in the study participated in a full day of interviews and exams 12 times over the course of the 38-year time line. Biological family history of smoking was also recorded for 99 percent of participants.

The researchers were able to look at a snippet of 880 of the participant’s DNA. These portions of DNA showed whether or not people had certain genes (CHRNA5-CHRNA3-CHRNA-4), which have been linked to smoking addiction in previous studies.

During interviews, the researchers evaluated each participant for nicotine dependence and asked when each participant had their first cigarette, when smoking became a daily habit, when heavy smoking started and about attempts to quit. 

The results of the study showed that neither trying smoking for the first time nor the age at which they first tried smoking had anything to do with genetics.

“Individuals at higher genetic risk were more likely to progress to smoking 20 or more cigarettes per day and did so more rapidly,” said the authors.

The researchers said teens with higher genetic risk for smoking addiction were 24 percent more likely to become daily smokers by 15 years of age and 43 percent more likely to become heavy smokers (20 or more cigarettes per day) by age 18.

Based on nicotine dependence evaluations, people with high genetic risk were 27 percent more likely to develop nicotine dependence over the course of the study.

People with high genetic risk were 22 percent more likely than those without high genetic risk to be unsuccessful in attempts to quit smoking.

“[C]hildren who our study would classify at high genetic risk are not guaranteed to become addicted if they try smoking, and, even more importantly, children we would classify at low genetic risk are not immune to addiction,” the authors said.

The authors recommended stronger efforts to prevent underage smoking, as people with high-risk genes were significantly more likely to be pack-a-day smokers by the age of 18. The authors also recommended increased efforts to encourage smoking cessation and make resources available to the public.

This study was published in March in JAMA Psychiatry.

The National Institute on Aging, the UK Medical Research Council, the US Agency for Health Care Research and Quality, the National Institutes of Mental Health and the National Institute on Drug Abuse provided funding for this project. No conflicts of interest were found.

Review Date: 
March 25, 2013