Dementia is a loss of brain function. The most common form of dementia is Alzheimer's disease. Dementia impacts at least 20% of the people over 85 and can result in the need for long-term care.
Some researchers believe that dementia is an inevitable part of our extended life expectancy, but other studies seem to indicate that it is not simply the number of years that matter. Dementia risk increases with certain lifestyle factors such as a diet and exercise. Think of the risk instead as the number of unhealthy years lived, not simply the number of years you have lived.
Genetic factors can increase the risk of dementia, but shared behaviors in families may increase the risk even further.
Dementia often first manifests through forgetfulness, difficulties with daily routines, problems speaking, personality changes, and loss of motivation.
Dementia does not appear in all cultures. Long-lived non-Western cultures have low prevalence of dementia. It is thought that lifestyle factors such as exercise, healthy eating and positive outlook prevent damage to the brain over time.