An estimated 5.4 million persons have Alzheimer's disease and there are up to 14.9 million unpaid caregivers for persons with Alzheimer's disease. Annual expenditures for the disorder top $183 billion, according to the Alzheimer's Association's 2011 Facts and Figures (http://www.alz.org/downloads/Facts_Figures_2011.pdf).
Alzheimer's disease is devastating for persons affected by the disorder. It also is a great source of anxiety for midlife adults.
Historically, risk factors for Alzheimer's disease have been somewhat elusive. There is a genetic component to the disorder but no single gene appears to convey strong hereditary risk. Rather, it is likely that several genes increase risk incrementally and only a few of these genes have been identified. Lifestyle factors may alter risk for the disease. For example, persons with more education are at lower risk for Alzheimer's disease but again, the effects here are not strong.
Newer evidence suggests that poor cardiovascular health may increase risk for Alzheimer's disease. Some of the most impressive data come from longitudinal studies of the cardiovascular risk factors, aging, and dementia (CAIDE) study out of Finland. The investigators followed participants for an average of 21 years, from age 50 to 71, and found that total cholesterol, smoking, and high systolic blood pressure at midlife were associated with greater risk for Alzheimer's disease later in life.