Women have a higher risk of heart attack even when they have fewer clogged arteries than men because their arteries are smaller and small plaque in them can be proportionally more dangerous.[1][4] Studies show that plaque rupture accounts for only 47% of heart attacks in women, while in men it accounts for 75%, meaning that more than half of heart attacks in women under 65 are caused by other factors.[4] Women are particularly susceptible to non-traditional causes of heart attack—spontaneous rupture of an artery (SCAD) affected 11% of women compared to only 0.7% of men, and an imbalance between oxygen supply and demand occurred in 34% of women versus 19% of men.[4] Health factors such as diet, exercise, smoking and blood pressure have a greater impact on cardiovascular risk in women than in men – women in average health had a 2.3 times greater risk of heart attack than those in ideal health, while men in average health had only 1.6 times the risk.[1] Women with diabetes have a 44% higher risk of heart complications than men, and smoking increases their risk of heart disease by up to 35% compared to men.[6] The protective effect of the hormone estrogen before menopause naturally protects women's hearts, but during and after menopause this protection weakens and the risk of heart disease increases.[3][6]