The rise of Alzheimer's disease in recent decades is a tragic side effect of a great success story: the increase in human longevity.
Alzheimer's disease is the relentless destruction of brain tissue, which causes a debilitating loss of mental capacity. Despite intensive study, only a few mitigating treatments exist, and the disease remains wholly incurable. So little is understood regarding its root causes that it is impossible even to provide definitive advice as to how it may be avoided. But one unsettling fact is clear: Alzheimer's will likely claim more and more victims in the years ahead. In developed nations, an estimated 2% of the population currently has the disease, and one study projects three times more by 2054. If such predictions are accurate, the potential human suffering and attendant financial burdens will be staggering.
The modern emergence of Alzheimer's may represent a confluence of several separate human health trends: improved public-health standards, development of novel medicines to combat infectious diseases, high-calorie diets rich in saturated fats, and general lifestyle changes. While reversing all these trends is impossible, understanding the factors underlying the emergence of Alzheimer's is now a vital facet in the effort to manage this dementia.
First and foremost, people live much longer than they did a century ago, and Alzheimer's is overwhelmingly an affliction of the aged. From 1900 to the present, the mean life expectancy for a U.S. resident increased from around 50 years to nearly 80 years. While the incidence of Alzheimer's is roughly 1% among 70-year-olds, it is 39% among those 90 to 95 years old.
Although it is cold comfort, the emergence of Alzheimer's is a consequence of sustained and successful efforts toward improving health that are enabling many more people to live long enough to develop dementia. People today have far better protection against once-rampant infectious diseases that ensured many an early death. Improved public sanitation, clean drinking water, effective antibiotics, widespread vaccination, and other measures have all contributed to substantially healthier lives.
Coupled with this huge success against many infectious diseases have been enormous alterations in people's nutrition habits and physical activity. Diets increasingly rich in calories and fats have been accompanied by a declining need for physical labor due to mechanization, the shift toward a service economy, and greater reliance on computerized information. In general, jobs demanding strenuous physical labor have decreased, while sedentary white-collar work has increased. So higher calorie consumption and less calorie-burning activity have created a population that is, on average, more overweight and less physically fit than ever. Obesity is linked to a significantly increased propensity to develop diabetes, heart disease, and hypertension. And recent research suggests that chronic circulatory conditions carry an increased risk for Alzheimer's development, as well.
Treating Alzheimer's Disease
Early-stage Alzheimer's patients can now be treated with drugs that improve cognitive function by allowing neuron chemical signals to last a bit longer in the brain. Although often of great benefit, this treatment is not a cure, and all Alzheimer's patients exhibit an irreversible mental capacity loss that follows a years-long process of neural cell destruction. Postmortem examination of Alzheimer's patient brains has revealed a striking correlation between unique neural tissue abnormalities and this dementia.
The patients accumulate large deposits of a peculiar small protein--amyloid--within and between the neurons and in the walls of blood vessels supplying the brain. Amyloid is formed when a much larger precursor protein is cut into small fragments by enzymes, and it might actually protect the brain by sealing blood vessel leaks that arise through trauma or aging, according to Alex Roher of the Sun Health Research Institute. …