For women who have history of having had a heart attack, their risk was doubled of having either mild cognitive impairment or dementia over time.
Women who had bypass surgery were at greatest risk. Researchers don't know why heart disease may be linked to dementia in older women, but say it's possible plaque in the arteries may also suggest plaque in vessels feeding the brain.
The study also found having risk factors like high blood pressure and diabetes increased risk for cognitive decline over time, even in women without heart disease.
If you know that you are at risk, then you can do more to help protect yourself.
The study also found that a being overweight or obese may actually protect against cognitive decline.