The Kimberley region of Western Australia is a land of vast and spectacular
natural beauty—ochre rock landscapes, plunging waterfalls, beaches
fronting the turbulent Indian Ocean. It is also home to a number of
Australia's indigenous people, collectively called Aborigines.
Yet in spite of the exquisite terrain, life for many of them is far from
ideal. Their physical health tends to be dismal. And they have now been found
to possess what may be the highest dementia rate in the world.
Specifically, Australian scientists have now found, after assessing 365
indigenous persons in the Kimberley region who were aged 45 or older, that
this population has a prevalence rate of dementia five times higher than that
of the general Australian population of comparable age—or 12.4 percent
versus 2.4 percent, the latter rate of which is similar to that in other
developed countries. Results were published online September 17 in
In fact, the prevalence rate of dementia among the subjects aged 60 or
older was 24 percent—perhaps the highest known prevalence rate for
dementia in the world, according to the scientists. They noted that the only
known prevalence rate that comes close was an Alzheimer's disease prevalence
rate of 21 percent reported for an elderly Arab community in Israel.
"We were surprised by these results," the lead investigator of
this study, Leon Flicker, Ph.D., a professor of geriatric medicine at the
University of Western Australia in Perth, told Psychiatric News."
It was previously thought that because of the high mortality in the
indigenous Australian population, older people were sparse, and dementia was
uncommon. But despite there having been lower numbers of older people, we
found very high rates of dementia, particularly in younger people."
The reason for this dementia "epidemic," Flicker speculated,
may be because indigenous Australians in the Kimberley region possess a number
of characteristics that in turn predispose them to dementia. For example, he
and his colleagues found that 60 percent of subjects over age 45 had no formal
education, 51 percent had experienced head injuries, 50 percent had poor
mobility, 43 percent had high blood pressure, and 42 percent had diabetes.
Flicker and his colleagues are now exploring ways whereby they can improve
both the mental and physical health of these individuals. For example, if they
could get the people to exercise more, it might not just benefit their
physical health, but reduce their risk of dementia.
Indeed, Flicker and his colleagues found in another recent study, which
they conducted in nonindigenous Australians, that exercise can improve
cognitive function in older adults at risk of dementia; that is, exercise is
beneficial in persons over age 50 who complain of mild memory problems. True,
many observational studies have already found that people who are physically
active seem less likely than sedentary persons to experience cognitive decline
and dementia in later life. But this study of 170 subjects, reported in the
September 3 Journal of the American Medical Association, appears to
be the first randomized, controlled trial to do so, according to Flicker and
Both studies were funded by the Australian National Health and Medical
An abstract of "High Prevalence of Dementia and Cognitive
Impairment in Indigenous Australians" is posted at<www.neurology.org/cgi/content/abstract/01.wnl.0000320508.11013.4fv1>.
An abstract of "Effect of Physical Activity on Cognitive Function in
Older Adults at Risk for Alzheimer's Disease" is posted at<http://jama.ama-assn.org/cgi/content/abstract/300/9/1027>.▪