Prospects for delaying the rising tide of worldwide, late-life dementias.

Worldwide, lifespan is lengthening. Concomitantly, late-life dementias are increasingly common, challenging both personal and public health internationally. After age 65, rates of dementia tend to double every five years in developed countries and every seven in developing ones. The late-life dementias, particularly Alzheimer's disease, have profound effects on aging individuals and their caregivers. Multidisciplinary research has explored the potential for various approaches to prevent or delay the onset of late-life dementias. Outlining that research, including our team's Adult Changes in Thought and Kame studies, this review concludes that delaying the onset of these dementias appears feasible, although absolute prevention may not be. Today, the most promising methods appear to include controlling vascular risk factors like hypertension and engaging in physical exercise - and possibly mental exercise. If people can delay the onset of dementias, they can lead more fulfilling lives for longer, spending less time suffering from dementia and letting their families spend less time coping with the disease. It is possible that trends toward more knowledge-based societies, where cognitive health is so vital, may increasingly exert evolutionary pressure favoring larger and healthier brains - and a "compression of cognitive morbidity" - well into old age. Public health's great triumph, increased lifespan, should give more of the world's people the reward of many years of dementia-free life. Rather than the personal difficulties and public health burdens of many years of functional impairment, dependency, and suffering with dementia, some interventions may delay the onset of Alzheimer's disease and other dementias.