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March 19, 2007 -- Quitting smoking and staying off cigarettes for more than a decade may erase some of the heart risks of smoking.
That news comes from an Irish study that compared arterial stiffness in 554 smokers, former smokers, and nonsmokers.? Healthy arteries are not stiff.
The study showed that the arteries of former smokers who had quit more than 10 years before were no more stiff than the arteries of lifelong nonsmokers. ?This suggests the effects of arterial stiffness from smoking "are reversible, although it may take more than a decade" to undo, write the researchers, from Ireland's Trinity College Dublin.? They include Azra Mahmud, MBBS, PhD, MRCPI.
Cigarette smoking is one of the most important risk factors for heart disease, note the researchers. But given enough time, some of that risk may fade, Mahmud's team says.
The study included 150 current smokers, 136 former smokers, and 268 lifelong nonsmokers.
The former smokers were 22 people who had quit smoking less than one year earlier; 40 who had quit smoking one to 10 years earlier; 60 who had quit smoking more than a decade earlier; and 14 who didn't note their quit-smoking date.
All participants -- smokers and nonsmokers alike -- had high blood pressure. But they weren't taking blood pressure drugs and they didn't have other conditions such as coronary artery disease, heart failure, or diabetes.
To start, the researchers tested participants' blood pressure and arterial stiffness.
As expected, current smokers had the stiffest arteries and nonsmokers the least stiff.
But among former smokers, those who had quit more than 10 years earlier had the same amount of arterial stiffness as the lifelong nonsmokers.
Meanwhile, ex-smokers who had quit less than a year earlier had arteries that were as stiff as those of the current smokers.
Smokers who had quit between one and 10 years earlier had less arterial stiffness than current smokers, but more than lifelong nonsmokers.
The results held when researchers considered the participants' age, sex,
heart rate, and BMI (body mass index, a ratio of height to weight used to
indicate obesity).
However, the study doesn't prove quitting smoking was the only reason for the improvement in arterial stiffness.
Participants weren't followed over time, and no chemical tests were done to confirm that people who said they didn't smoke truly didn't smoke. It's also not clear if people who had quit smoking had made other healthy lifestyle changes.
Even so, the researchers write that the study suggests the effects of
arterial stiffness from smoking "are reversible, although it may take more
than a decade" to undo.
The study appears in the journal Hypertension.