Study: Fewer middle schoolers smoking

New research shows genetic differences in the way the body handles nicotine makes it more likely that a young person becomes a life-long smoker.

Doctors from the universities of Wisconsin and Utah examined tiny differences in a gene involved in nicotine processing. About 40 percent of people had mutations that greatly increase the odds of being a heavy smoker as an adult. But that addiction was more likely to take hold if they started the habit by 17.

There's hope this discovery will help experts design more personalized treatments for smokers.