Narrator: This is Science Today. New research suggests adolescent smokers are more susceptible to long-term DNA damage than adult smokers. John Wiencke, a professor of epidemiology at the University of California, San Francisco examined DNA damage in former smokers who now have lung cancer.
Wiencke: About a quarter of those patients who were undergoing surgery for their lung cancer, reported that they started smoking when they were seven or eight or nine or ten years of age - which really shocked me. I think the average is about seventeen years old.
Narrator: One reason these former, adolescent smokers have more DNA damage may be the fact their lungs were in the early stages of development at the time.
Wiencke: We don't want to discourage people from quitting smoking by any stretch of the imagination, but the benefits are not immediate. The fact is the most recent population data does suggest that even many, many decades after smoking - depending on your level of smoking - you still have an excess risk for lung cancer.
Narrator: For Science Today, I'm Larissa Branin.