(HealthDay)—Adding to the arsenal of evidence that smoking is bad for you, a large new study indicates that lifetime smokers cut 10 years off their life expectancy—a decade they can gain back if they quit before age 35.
Using data from more than 200,000 Americans, researchers also found that the death rate for current smokers is three times as high as those who never smoked, with most of the extra deaths caused by smoking-related conditions such as cancer, heart disease, stroke and respiratory diseases.
Experts hailed the study as landmark, noting that similar studies in the United States were done decades ago or on groups of people who didn't represent the general population. Because smoking among women didn't peak until the 1980s, the research is apparently also the first to examine the true impact of tobacco use among both genders.
"This is really striking—a combination of good news for nonsmokers, but much higher death rates among smokers," said study author Dr. Prabhat Jha, founding director of the Center for Global Health Research at St. Michael's Hospital in Toronto. "We found a tripling of the mortality rate, and men and women are now very similar. Women smoke like men and die like men."
The study is published in the Jan. 24 issue of the New England Journal of Medicine.
According to the U.S. Centers for Disease Control and Prevention, tobacco use accounts for nearly 200,000 deaths annually in the United States—more than HIV infection, drug or alcohol use, car accidents, suicides and murders combined.
American, Canadian and British scientists examined data on smoking status from nearly 217,000 adults from the U.S. National Health Interview Survey between 1997 and 2004 to determine the hazards of smoking and benefits of quitting.
Nonsmokers are twice as likely to live to age 80 compared to smokers—indicating that smoking isn't just killing people in old age, but in middle age, the study said. Another startling find was that adult smokers who quit at ages 25 to 34, ages 35 to 44 or ages 45 to 54 gain about 10, nine and six years back, respectively, compared to those who continue to smoke.
Even quitting after age 55 should net former smokers extra years, Jha said.
"It's never too late to quit," he said. "Even if you quit by age 60, you get four years back. That's a fair proposition—and four good years of life is probably worth it."
Dr. Norman Edelman, chief medical officer of the American Lung Association, praised the study for sharply demonstrating the dangers of smoking and benefits of quitting.
"They used a very large database, so the chance that this is accurate is really high . . . and the way they present it is very easy to understand," Edelman said. "The numbers are very, very compelling, and it points out that smoking prevention and cessation is still the most important public health challenge we have in the United States."
Efforts to eliminate smoking in public places and place higher taxes on cigarettes have all helped cut the prevalence of smoking, Edelman noted, but more research is still needed to help understand the science behind nicotine addiction and steer adolescents away from tobacco.
Explore further: Women smokers who quit before 40 gain nine years in lifespan
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The U.S. Centers for Disease Control and Prevention offers a fact sheet about the health risks of smoking.