More Than 3 Million Have Dementia
Nearly 1 in 7 Adults Aged 71 and Older Have Dementia; Alzheimer's Is the Most Common Type of Dementia
Oct. 31, 2007 -- Almost one in seven U.S. adults aged 71 and older -- about
3.4 million people -- have dementia, a new study shows
Most of those elders with dementia -- 2.4 million people -- have Alzheimer's
disease, according to Duke University's Brenda Plassman, PhD, and
They reviewed data on a nationally representative group of 856 people aged
71 and older, including people in nursing homes.
The elders took tests of mental skills including memory, language, and
attention to screen for dementia. They also provided blood samples and noted
their depression, medications, medical history, and family history of memory
- Almost 14% of the participants had dementia.
- About 10% had Alzheimer's disease.
- Dementia became more likely with age.
Dementia was more likely for people with a gene glitch linked to Alzheimer's
disease, less likely for highly educated people, and equally likely for men and
Plassman and colleagues also combined their findings with results from
previous dementia and Alzheimer's disease statistics in people as young as
"This resulted in an estimated total of 3.8 million individuals with
dementia and just over 2.5 million with Alzheimer's disease in the USA,"
write the researchers.
They note that the only previous national estimate of dementia prevalence
was 2.9 million people with dementia.
As the U.S. population ages, dementia will likely become more common,
Plassman's team predicts. However, dementia isn't a normal part of aging.
The dementia statistics study appears online in