FRIDAY, March 24, 2006 (HealthDay News) -- Everyone knows that smoking kills, but a new study finds it can kill much earlier than most people realize.
Researchers in Norway tracked more than 50,000 people for a quarter century, and found that smokers were much more likely to die in middle age than nonsmokers.
But the study also showed that the risk quickly dropped when a smoker quit.
"This finding reinforces the message that its never too late to quit smoking," said Dr. Ronald M. Davis, director of the Center for Health Promotion and Disease Prevention at the Henry Ford Health System in Detroit, and author of an accompanying editorial. "The benefits are larger if you quit at a lower age, but there are significant benefits at any age."
The study, which is the largest and longest study of smoking and its consequences involving both men and women, appears in the current issue of the Annals of Internal Medicine.
The researchers collected data on nearly 50,000 men and women, smokers and nonsmokers, between 1974 and 2000.
They found that, among the men, 41 percent of heavy smokers (a pack or more a day) died in middle age, defined as age 40 to 70, compared to 14 percent of those who never smoked. The middle-age death rate for women who smoked heavily was 26 percent, compared to 9 percent of those who never smoked.
The good news: "We observed substantially lower risk for death among those who quit smoking in all decades of middle age," the researchers reported.
For John F. Banzhaf, executive director of the Washington-based organization Action on Smoking and Health, the study is valuable because "it emphasizes middle age."
"All too many people, when they think of smoking, think of people dying at an old age," Banzhaf said. "This study shows a very dramatic increase in death rate at middle age, a significantly lower chance of surviving middle age, particularly if you are what they define as a heavy smoker -- one pack a day."
Davis and Banzhaf agreed that there's real value to giving up smoking, even after the habit has already done major physical damage.
"Even if you have heart disease or cancer, quitting smoking is beneficial," Davis said. "For someone who has had a heart attack, quitting reduces the chance of having a second heart attack. For someone with cancer, quitting means it is less likely they will get a second cancer or pneumonia."
Banzhaf said he often gets calls from families of people with cancer, asking why it is necessary to stop smoking. "I say that if you smoke, you increase the rate at which the cancer spreads and, if it is operable, the chance that an operation will help," he said. "It also causes a decline in the ability to engage in useful activities."
Middle-aged smokers who haven't been hit by a smoking-related illness "may think that if they've lasted this long, they're not susceptible to the dangers of smoking, or that the damage is already done," Davis said. "These are myths we need to correct, and this study can help."
For help on quitting smoking, head to the U.S. Centers for Disease Control and Prevention.