By Bill Berkrot and Ransdell Pierson

DALLAS (Reuters) - Some cigarette smokers over 65 years old who kick the habit may be able to reduce their risk of dying from heart-related problems to the level of those who never smoked far faster than previously believed, according to new research presented on Wednesday.

Previous research found that older former smokers who had consumed less than 32 pack years of cigarettes could reduce their risk of dying from heart disease to the level of lifelong nonsmokers after 15 years.

The pack year measure is derived by multiplying the number of cigarettes smoked per day by the number of years a person was a smoker. For example, 32 pack years would be 3.2 packs a day for 10 years or two packs a day for 16 years.

"The new finding is if you smoke less than 32 pack years, you might become like never-smokers much sooner than 15 years," said Dr. Ali Ahmed, who reported the findings at the American Heart Association scientific meeting in Dallas.

Many people in the study lowered the risk of developing heart failure, or risk of dying from heart failure, heart attacks and strokes to the same level as those who never smoked in nearly half the time as previous research had indicated.

"For half of them, it was eight years after cessation," said Ahmed, a professor of cardiovascular disease at the University of Alabama at Birmingham School of Medicine.

"Even for the heavier smokers, who smoked more than 32 pack years, compared to current smokers, they will significantly reduce the risk of total mortality by 35 percent (by quitting), so there's a positive message for everybody," said Ahmed.

Cutting the risk to the level of never-smokers was a much higher bar than comparison with current smokers, Ahmed added.

Researchers compiled their data by analyzing 13 years of medical information from the Cardiovascular Health Study begun in 1989 and sponsored by the National Heart, Lung, and Blood Institute. They compared 853 people who quit smoking 15 or fewer years before with 2,557 people who never smoked cigarettes. Of the former smokers, 319 had smoked less than 32 pack years.

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Smoking remains the most preventable cause of early death in the United States and elsewhere. So the main message remains: "If you smoke, quit and quit early," Ahmed said.

But even those who do not stop smoking until they reach the Medicare-eligible age of 65 appear likely to derive heart health benefits from stopping.

While the heart-related mortality benefits seen in the study seem clear, researchers said, lung damage is not as easily reversible. Those who smoked less than 32 pack years and quit up to 15 or more years ago were still at higher risk of dying from lung cancer, emphysema or chronic obstructive pulmonary disease.

(Reporting by Bill Berkrot; Editing by Lisa Von Ahn)