Stroke Risk Increases With Number of Years Spent Smoking

Here’s some weighty news for heavy smokers: Your risk of stroke hinges as much on how many cigarettes you puff a day as on how many years you light up, a new study shows.

“It matters both how long you smoked and how much you were smoking at the time,” says researcher Sachin Agarwal, MD, MPH, a postdoctoral fellow in cardiovascular medicine at Johns Hopkins Hospital in Baltimore, Md.

A person who smokes two packs a day for 10 years, in other words, faces the same risks as a person who smokes one pack a day for 20 years, he says.

Previous studies have shown that five to 15 years after kicking the habit, former smokers’ stroke risk drops to that of people who have never taken a puff. But those studies generally considered only how much time had passed and not how many packs of cigarettes a person smoked each day, he says.

“For new smokers, the message is, if you can’t stop, take a good look at how much you are smoking,” Agarwal tells WebMD.

Larry B. Goldstein, MD, director of the Duke Center for Cerebrovascular Medicine at Duke University in Durham, N.C., and an American Heart Association spokesman, agrees. “People who can’t quit should at least smoke as little as possible,” he says.

Predicting Stroke Risk

The new study, presented here at the International Stroke Conference 2006, included a total of 42 men and women; 15 of them had never lit up and 27 of them were former smokers.

The 27 former smokers had quit an average of 30 years previously. Their average smoking exposure over their lifetime was 20 pack-years, which was calculated by multiplying the number of years smoked by the number of packs smoked daily.

Then, the researchers used magnetic resonance imaging (MRI) to compare the thickness of the walls of the carotid arteries of the former smokers and the "never" smokers. Carotid arteries are important blood vessels that supply oxygenated blood to the brain. It is your carotid artery that you feel when you check your pulse at the side of your neck.

Atherosclerotic plaque can build up in one or both of the neck arteries, which can increase your risk for stroke. By measuring thickening of the walls of the carotid arteries, researchers can measure the amount of plaque buildup, Agarwal explains.

“Many studies have shown that atherosclerosis, as assessed by increased thickness of the carotid artery wall, is directly predictive of an increased risk of heart attack or stroke,” he says.

The MRI images showed that carotid wall thickness increased progressively, depending on how many pack-years a person smoked.

The bottom line, Agarwal says, “is that pack-years are the more important predictor of stroke risk.”

Benefits of Quitting

So should longtime heavy smokers give up all hope of ever getting their health back? “Definitely not,” Goldstein tells WebMD.

No matter how long you smoked and how much you smoked, “there are numerous health benefits to stopping, from a lower risk of stroke to a lower risk of cancer,” he says. Plus, parents who puff away should always keep in mind what they are doing to their kids, he says.

“Parents who smoke are poisoning their children,” says Goldstein, pointing to the known risks of secondhand smoke.

“There’s nothing worse than passing a car in which the kids are strapped safely in their safety seats, but the vehicle is filled with smoke,” he says.

By Charlene Laino, reviewed by Louise Chang, MD

SOURCES: Sachin Agarwal, MD, MPH, postdoctoral fellow in cardiovascular medicine, Johns Hopkins Hospital, Baltimore. Larry B. Goldstein, MD, director, Duke Center for Cerebrovascular Medicine, Duke University, Durham, N.C.; and spokesman, American Heart Association.