A 2005 Finnish study revealed that middle-age men and women who exercise at least twice a week and eat a healthy diet can reduce their risk of developing Alzheimer's Disease (AD) by 50% in old age.  Previous studies have shown that people with high blood pressure, high cholesterol, and who are overweight/obese could have a greater risk of AD than those with a more active, healthy lifestyle.

Worldwide, 37 million people live with dementia, with Alzheimer's Disease causing the majority of cases. ~2001 Statistic, World Health Organization