Mental decline may be associated with heart disease.  Help your heart help your brain: keep blood pressure low, control cholesterol, don't smoke, and take statins.
D001921:Brain / Q000098:blood supply; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control*; D006331:Heart Diseases / Q000150:complications / Q000517:prevention & control*; D006801:Humans; D020521:Stroke / Q000150:complications / Q000517:prevention & control