Stroke has long been considered a "man's disease," but that notion seems to hold no more. Each year in the United States, 46,000 more women than men have a stroke, and three out of five deaths from stroke occur in women. What's more, if you think that breast cancer is a woman's biggest health concern, think again. A woman's lifetime risk of breast cancer is one in nine, but nearly one in five women over age 45 will have a stroke by the time they reach age 85.

The differences in stroke between men and women don't just lie in the statistics. Women have some unique risks and different responses to shared risks. They also respond better than men to certain preventive measures. For example ...

Stroke Risk-Factor 1 -- Aging. Women ages 30-50 have a five times lower risk of stroke than men, but this difference disappears when women hit menopause. That's when estrogen levels drop substantially and low-density lipoprotein (LDL) cholesterol levels begin to rise, which spurs along the process of atherosclerosis, the gradual buildup of plaques that narrow arteries and can lead to ischemic strokes.

Stroke Risk-Factor 2 -- Heredity. Women are more likely than men to inherit a risk of ischemic stroke. In a recent study from the United Kingdom, women who suffered a stroke were 40% more likely than men to have a parent or sibling with a history of stroke.

Stroke Risk-Factor 3 -- Hormone replacement therapy. Researchers had once hoped that hormone replacement therapy would protect women from strokes, but the truth is the therapy slightly increases stroke risk. As a result, experts no longer recommend estrogen with or without progestin to lower stroke risk in women.

Stroke Risk-Factor 4 -- Atrial fibrillation. Women with this heart rhythm irregularity are more likely to have an ischemic stroke than men. In a recent study of nearly 14,000 adults with atrial fibrillation, 4% of the women not taking warfarin to prevent blood clots had an ischemic stroke, compared with 2% of the men. Fortunately, warfarin was just as effective in preventing ischemic strokes in the female participants as it was in the men.

Stroke Risk-Factor 5 -- Lipid abnormalities. High cholesterol is a risk factor for ischemic strokes, and a recent 11-year study found that high total and LDL cholesterol levels doubled the chances of having a stroke in about 28,000 healthy women ages 45 and older. Research also suggests that having high triglycerides may increase stroke risk more for women than for men.

Stroke Risk-Factor 6 -- Migraines. Women who have migraines with aura (visual disturbances such as light sensitivity; seeing lines, spots, or flashes of light; or temporary vision loss) are up to 10 times more likely to suffer a stroke, depending on what other stroke risk factors they have.