Genes may play role in nicotine addiction in teens

Genes may determine which teen smokers get hooked for life, according to a study that could shed new light on treating and preventing tobacco addiction.

Young, white smokers with certain gene mutations who pick up the habit before age 17 are up to five times more likely to struggle with a lifelong nicotine addiction than their peers who don't have the DNA variants, researchers said. The study, by University of Utah and University of Wisconsin scientists, appeared in the journal Public Library of Science.

Whites with the gene variants who began smoking cigarettes at or after age 17 didn't raise their risk of later addiction, researchers found.

The findings stress the importance of focusing nicotine treatment and education programs on teenagers before they start smoking, Dr. Nora Volkow, director of the National Institute on Drug Abuse, said. About 10 percent of 12- to 17- year-olds used cigarettes in the past month, according to 2006 data from the U.S. Department of Health & Human Services.

"The study shows that if you can delay smoking you may actually be able to prevent nicotine addiction," said Volkow. "The risk that is conferred by these genes is only applicable if subjects start to smoke early in life. If they initiate smoking later, it doesn't really make them more likely to be addicted once they pass that point."

The gene variations are found in about 38 percent of Americans of European descent, researchers said.

"This is a first step in underlining the components of addiction during that time period," said Dr. Robert Weiss, professor of human genetics at the University of Utah and lead author of the study. "These types of findings may help us to refocus why that period of adolescence is so important to long-term susceptibility and the struggle people have with nicotine dependence."

The researchers studied 2,827 whites identified as long-term smokers. The genetic changes linked to increased susceptibility to tobacco addiction occur in different frequencies in different racial and ethnic groups, the study said.

A greater percentage of whites, 31.4 percent, use tobacco than Hispanics, Asians or African-Americans, according to the HHS. Twice as many whites, 12.4 percent, than blacks age 12 to 17 have smoked cigarettes in the last month, according to HHS.

Participants in the study were classified as long-term smokers based on the age they began smoking daily, the number of years they smoked, and the average number of cigarettes smoked a day, the study said.

Other factors beyond genetics, such as environment and the age at which someone begins to smoke, remain prominent indicators of the likelihood someone will develop an addiction to smoking, Volkow said.

"I'm a little scared of saying we're going to tailor interventions toward kids that have these genetic elements," Volkow said. "You do not want then to become complacent and ignore others because they are still at high risk of abusing substances."

An estimated 62 million Americans ages 12 or older smoked cigarettes in the last month, according to the HHS data.

More than 6 million of those who start smoking younger than 18 will later die from a smoking-related disease, according to the agency.