Cigarettes: The lung cancer risk lingers

In April 2005, ex-smokers were reminded that the habit they kicked may come back to haunt them. The newscaster Peter Jennings announced that he has lung cancer, even though he quit smoking 20 years ago (except for a brief relapse after the September 11, 2001, terrorist attacks).

Smokers who quit are rewarded quickly when it comes to heart disease. Within a year, their risk drops to half that of active smokers. After 15 years, it approaches that of people who've never smoked at all. This is great news because the risk of dying young from heart disease is so much greater than it is from cancer, for smokers and nonsmokers alike.

Now for the bad news. As perhaps evidenced by Jennings, the lung cancer risk from smoking fades more slowly than it does for cardiovascular disease, perhaps because of lasting DNA damage to lung cells. Even 10–15 years after quitting, several studies have shown that an ex-smoker is several times more likely to die of lung cancer than someone who has never smoked. A study published in early 2005 found that former smokers are also more vulnerable to the effects of secondhand smoke in the workplace, even if they haven't lit up for the last 10 years.

Does the lung cancer risk ever go away? That may depend partly on how old you are when you quit. A study in the April 2005 Annals of Epidemiology reported that women who quit before age 30 are no more likely to die from lung cancer than their counterparts who never smoked. British and Japanese researchers have also reported an earlier-the-better age effect. On the other hand, a study of American veterans started in the 1950s showed that even 40 years later, former smokers had a 50% greater chance of dying from lung cancer compared with lifetime nonsmokers.

Still, here's an area where quitters prosper: Even people who shake the smoking habit in their 60s substantially reduce their lung cancer risk — and add several years to their life expectancy.