Smoking increases the risk of having a stroke among women, according to a study published in the August 15 issue of the journal Stroke.

The risk was 2.2 times greater for women smoking one to 10 cigarettes a day, 4.3 times greater for those smoking 21 to 39 cigarettes a day, and 9.1 times greater for those smoking two packs a day or more, compared to nonsmokers, the study found.

Dr John Cole, the study's author, said the research is significant as it provides actual dose response, which was non-existent in the past.

Cole and his colleagues interviewed 466 women who had had a stroke, and also 604 women who hadn't. Those being interviewed were all between 15-49 years old.

The study also demonstrated the benefit of quitting smoking. Stroke risk declined as early as 30 days after a woman gave up smoking and returned to normal in about two years.

"Stopping is the best thing to do, but cutting back will also reduce the risk," Cole said.

Smoking raises the risk not only of stroke but also of heart disease by damaging blood vessels and making blood clots more likely, Cole said.

About 20 percent of young American women are smokers, the report noted.

Cole said a similar study on men is planned.

(Xinhua News Agency August 17, 2008)