Genes May Determine Smoking Addiction

Genes may not make a person more likely to try a cigarette, but they could determine who becomes addicted to smoking.
Researchers from Duke University looked at 1,037 men and women who were a part of the Dunedin Multidisciplinary Health and Development Study of New Zealand, which had followed participants from birth to age 38 to study their behaviors, health, and lifestyles. They created a “genetic risk score” by looking at gene markers thought to be linked to heavy smoking and, when they applied this to the study participants, they got a genetic risk score that could predict who might become pack-a-day smokers.
“These genetic risks were very much about smoking behavior earlier in life,” said Daniel Belsky, a post-doctoral research fellow at Duke University's Center for the Study of Aging and Human Development and the Duke Institute for Genome Sciences & Policy. “People with the increased risk went quickly from trying their first cigarette to becoming a heavy smoker.”
Of the people in the study, 880 had tried cigarettes. The genetic risk score could not predict who would try smoking, but the researchers found that those with high-risk genetic profiles were 24 percent more likely to become daily smokers by age 15, and 43 percent more likely to smoke a pack a day by age 18. Adults with high-risk genetic profiles were 27 percent more likely to become nicotine dependent and 22 percent more likely to fail in their attempts to quit smoking.
The high-risk factor, however, did not change the rate of addiction in people who started smoking as adults, Belsky said.
“This association only occurred in people who had started smoking regularly in their teens,” he said. “Most people try cigarettes as a teen, but only some of them become regular smokers as teens. That group is the one where genetic risk is most potent.”