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).
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.
This research is promising. Cardiovascular factors are relatively newly identified risks for Alzheimer's disease and the more we can learn about risk for AD, the greater the hope for preventing or even eradicating the disorder. Further, cardiovascular risk factors are modifiable. Unlike risk factors over which we have no control, such as aging and genes, there are effective ways to improve one's heart health.
Losing a few pounds, walking a couple of miles per day, and eating more whole grains, fruits, and vegetables can have small but additive effects that could potentially lower risk for AD in the decades that intervene between midlife and older age, traditionally defined as beginning at age 65. Indeed, midlife health may be particularly important for Alzheimer's disease risk because poor heart health at age 45 or 50, if not corrected, can have strong effects on future health due to accumulating damage on organ systems that supply the brain with necessary oxygen and nutrients. We all would do well to listen to the wisdom of the heart and take good care!