In fact, women who smoke have heart attacks nearly 14 years earlier than women who don't smoke, Norwegian doctors reported in a study presented to the European Society of Cardiology. For men, the gap is not so dramatic; male smokers have heart attacks about six years earlier than men who don't smoke.
"This is not a minor difference," said Dr. Silvia Priori, a cardiologist at the Scientific Institute in Pavia, Italy. "Women need to realize they are losing much more than men when they smoke," she said. Priori was not connected to the research.
Dr. Morten Grundtvig and colleagues from the Innlandet Hospital Trust in Lillehammer, Norway, based their study on data from 1,784 patients admitted for a first heart attack at a hospital in Lillehammer.
Their study found that the men on average had their first heart attack at age 72 if they didn't smoke, and at 64 if they did.
Women in the study had their first heart attack at age 81 if they didn't smoke, and at age 66 if they did.
After adjusting for other heart risk factors like blood pressure, cholesterol and diabetes, researchers found that the difference for women was about 14 years and for men, about six years.
Previous studies looking at a possible gender difference have been inconclusive.
Doctors have long suspected that female hormones protect women against heart disease. Estrogen is thought to raise the levels of good cholesterol as well as enabling blood vessel walls to relax more easily, thus lowering the chances of a blockage.
Grundtvig said that smoking might make women go through menopause earlier, leaving them less protected against a heart attack. With rising rates of smoking in women - compared with falling rates in men - Grundtvig said that doctors expect to see increased heart disease in women.
"Smoking might erase the natural advantage that women have," said Dr. Robert Harrington, a professor of medicine at Duke University and spokesman for the American College of Cardiology.
Doctors aren't yet sure if other cardiac risk factors like cholesterol and obesity also affect women differently.
"The difference in how smoking affects women and men is profound," Harrington said. "Unless women don't smoke or quit, they risk ending up with the same terrible diseases as men, only at a much earlier age."