Women who smoke have an increased risk for vascular mortality, but this is eliminated once they give up, say US researchers.

"A more rapid decline in risk after quitting smoking compared with continuing to smoke was observed in the first 5 years for vascular diseases compared with other causes," the authors write in the Journal of the American Medical Association.

Stacey Kenfield (Harvard Medical School, Boston, Massachusetts) and colleagues assessed the relationship between smoking and mortality in 104,519 female participants in the Nurses' Health Study.

From 1980 to 2004, 12,483 participants died, of whom 35.9% had never smoked, 28.9% were current smokers, and 35.2% were past smokers.

In all, 2957 participants died of vascular disease. Of them, 1385 died of coronary heart disease (CHD).

Current smokers were significantly more likely to die from any major cause during follow-up than never smokers (hazard ratio [HR]=2.81, p<0.001).

In particular, they were almost four times more likely to die from CHD than never smokers (HR=3.91, p<0.001).

Individuals who had quit smoking in the past 5 years had a 13% reduction in the risk for all-cause mortality compared with those who continued to smoke.

Of note, 61% of the full potential benefit of quitting smoking with regard to CHD was realized in the first 5 years of stopping smoking.

Kenfield and co-workers conclude: "Quitting reduces the excess mortality rates for all major causes of death examined. Most of the excess risk of vascular mortality due to smoking may be eliminated rapidly upon cessation."
They add: "Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs."

JAMA 2008; 299: 2037-2047