Smoking increases heart risk more in women than men

A study of 2.4 million people, published in the Lancet, showed a 25 percent difference in increased risk.

The reasons are unclear, say researchers. The British Heart Foundation said the findings were "alarming" especially as women tended to smoke fewer cigarettes. The World Health Organisation lists heart disease as the world's biggest killer, affecting more than seven million people each year. Smoking is one of the main causes. A study by the University of Minnesota showed women are at greater risk from smoking than men.