Studies suggest that ex-smokers may face increased health risks from cigarettes for years to come.
Some of the damage that cigarettes inflict on the body subsides quickly, halving the risk of heart disease and stroke within five years after a smoker quits.
But the effect of smoking on risks of cancer and other diseases can persist for decades, experts say.
Even Sen. John McCain (R-Ariz.), 71, who quit smoking in 1980, still faces some increased risk of cancer from smoking two packs a day for 25 years, studies suggest.
President Barack Obama (D-Ill.), 46, who says he has struggled to stay off cigarettes since quitting last year, may have less long-term risk because he smoked fewer cigarettes per day.
Better to Quit Smoking When Still Young
A major message of the research is that people who quit at a young age are far better off than those who put it off until later.
Obama and McCain, both of whom waited until their mid-40s to quit, would have been measurably better off if they had stopped a decade sooner, experts said.
“If you quit by age 35, by the time you’re 45 you look pretty much like a never-smoker in most of our profiles of risk,” said Terry Pechacek, associate director for science at the federal Centers for Disease Control and Prevention’s office on smoking and health.
The danger intensifies as smokers approach their 30th year of addiction, Pechacek said.
The risk of getting lung cancer for a person who has smoked for 30 years can be six times greater than the risk for someone who has smoked for 20 years.
Some of smoking’s effects may be irreversible. For example, the chronic bronchitis that many smokers develop heals only partially. And quitting cigarettes often has little effect on emphysema, which stems from the damage that cigarette smoke can cause in the lung’s fine structures.
“That stuff doesn’t repair itself,” said Dr. Norman Edelman, chief medical officer for the American Lung Association.
Getting other risks down to normal can take time. A study published last month in the Journal of the American Medical Association found that among women who smoked for 20 years on average, it took 30 years after quitting for their risk of lung cancer to reach normal levels.
Yet heart disease risks declined much more rapidly, the study found. Within five years of quitting, the excess risk from smoking had fallen by 61 percent.
“Clearly there are immediate benefits for some diseases,” said study co-author Stacey Kenfield, a researcher at the Harvard School of Public Health. “It’s never too late to stop.”
Cancer risks are more difficult to get back to normal because of how that disease progresses in the body, experts said.
Each cigarette has the potential to inflict small bits of genetic damage that can accumulate over time and cause cancer later in a smoker’s life. The longer a person smokes, the more cells get damaged, and the longer it takes for the body’s repair mechanisms to remove the damaged cells.
Smoking is Like Climbing a Mountain
Pechacek of the CDC compared the process to climbing a mountain; smoking more cigarettes takes a person farther up the slope. “If you smoke too long, [you] may not have enough years left to get back down to the base,” he said.
One measure of an ex-smoker’s risk is expressed in “pack-years,” the number of packs smoked per day multiplied by the number of years a smoker was addicted. McCain, who smoked two packs a day for 25 years, would have about 50 pack-years, while Obama, who smoked less than one pack a day for about as long, would have fewer than 25 pack-years.
Smoking Risk Calculator
Memorial Sloan-Kettering Cancer Center in New York has posted an online lung cancer prediction calculator (at mskcc.org/mskcc/html/12463.cfm) that uses pack-years and other information to assess an ex-smoker’s risk of developing cancer. Some researchers have debated the usefulness of pack-years in such predictions, arguing that overall duration of smoking matters more than the number of cigarettes smoked.
Like many smokers who try to kick the addiction, Obama says he has suffered smoking relapses since first attempting to quit last year. Such setbacks are less important than the ultimate goal, Pechacek said.
“Usually it takes three or four quits before a person is successful,” he said. “We need to stop looking at those as failures, because really they’re steps toward success. You’re building the skills you need to quit.”
Source: Jeremy Manier – Chicago Tribune