NEW YORK - Women who smoke cigarettes are more likely to develop heart disease than men who smoke, with the risk for women increasing every year that they smoke, according to a study.

The authors, led by Rachel Huxley of the University of Minnesota, reviewed studies published between 1966 and 2010 on 2.4 million people, including 44,000 cardiac events.

They found female smokers have a 25 percent greater risk for coronary heart disease than male smokers - the difference increases by 2 percent for each year women smoke.

"Prevalence of smoking is increasing in women in some populations and is a risk factor for coronary heart disease," wrote Huxley and her colleagues in The Lancet.

"Whether mechanisms underlying the sex difference in risk of coronary heart disease are biological or related to differences in smoking behavior between men and women is unclear. Tobacco control programs should consider women, particularly in those countries where smoking among young women is increasing."

A fifth of the world's 1.1 billion smokers are women, and an analysis released in March said millions of women in developing economies risked disease and death as their rising economic and political status leads them to smoke more.

"It hasn't been widely recognized that there had been this sex difference," Huxley said.

"For example, there are some data that indicate women will absorb more of the harmful agents in cigarettes compared with men. Women may inhale more smoke or they may smoke more intensively."

Huxley said her next step is to complete a similar study to examine if the same finding can be applied to other complications related to smoking, such as stroke.