The human appetite for longevity is seemingly insatiable. As long as we are enjoying reasonably good health, the vast majority of us have an Energizer Bunny–like desire to go on and on beyond our biblical “three score years and ten.” And we are equally desirous of holding on to all of our mental marbles during our extended ride into the sunset. But there is a specter haunting our dreams of lengthy and fulfilling retirement—the specter of Alzheimer disease (AD).
Both the incidence and prevalence of AD grow exponentially between ages 65 and 95 years, doubling every 5 years.1 Thus it seems that our dual desires for longevity and intact cognition are somewhat at odds with one another, since achieving the former jeopardizes the latter. The feared dementia of AD does not, however, arise instantaneously, springing full-blown like Athena from the head of Zeus. Rather, the journey from normal to demented includes transit through the newly mapped territory of mild cognitive impairment (MCI), whose borders blur with normality at entry and morph into those of subtle dementia on exit.2- 3