Research suggests women smokers face a greater risk of heart attack than male smokers.
A study of 2.4 million people, published in the Lancet showed a 25% difference in increased risk.
The research, carried out by United States-based scientists in a number of countries including Singapore, Norway and Turkey, analysed 75 sets of data produced by studies between 1966 and 2010, the BBC reports.
Researchers say the reasons for the increased risk to women smokers is unclear.
The authors suggest women might extract a greater quantity of carcinogens and other toxic agents from the cigarettes than men, which may also explain why women have higher rates of lung cancer than men who smoke.
