Average Dementia Survival: 4.5 Years
Study of Dementia Patients Shows Women Live Slightly Longer Than Men
Jan. 10, 2008 -- The average survival time for people diagnosed with dementia is about four and a half years, new research
shows. Those diagnosed before age 70 typically live for a decade or longer.
In an effort to learn more about survival characteristics among patients
with Alzheimer's disease or other dementias, researchers
from the U.K.'s University of Cambridge followed 13,000 people who were aged 65
and older for 14 years.
During the follow-up, 438 of the study participants developed dementia and
356 of these people died.
Overall, women lived slightly longer than men after a diagnosis of dementia
-- around 4.6 years vs. 4.1 years. And frailer patients died sooner than
But being married, living at home, and even degree of mental decline were
not found to have a big impact on survival.
The research is published in the Jan. 11 issue of the journal BMJ Online
"When we took everything into account, the big predictors of how long
people survive remain sex, age, and functional ability," University of
Cambridge professor of epidemiology Carol Brayne tells WebMD. "Functional
ability was a much better marker of how close someone was to death than
Dementia and Early Death
Across the globe, dementia rates are expected to double every 20 years for
the foreseeable future, with an estimated 81 million cases by 2040.
It is clear from earlier studies that people with dementia have decreased
survival compared with people without dementia. Even mild mental impairment
linked to dementia is associated with an increase in death risk.
But the characteristics associated with mortality among patients with
dementia have not been well understood.
There is general agreement that women with dementia tend to live slightly
longer than men, but the impact of other characteristics, including education
level, age at diagnosis, and marital status are less well known.
And many previous studies have been restricted to patients being treated for
the disorder by a specialist or in a hospital setting, Brayne says.
"We wanted to see what is happening with the entire population, not just
people who are treated for dementia," she says.
Slightly over two-thirds of the people in the study who developed dementia
were women, and the median age at dementia onset was 84 for women and 83 for
The median age at death was 90 for women and 87 for men. And average
survival times varied from a high of 10.7 years for the youngest patients
(65-69 years) to a low of 3.8 years for the oldest (90 or older at
People with higher education levels had slightly shorter survival times than
those with lower education, but the difference was not significant. Living in a
nursing home was also associated with slightly shorter survival than living at
home, but, again, the difference was not significant.
As in other studies, dementia was associated with shorter survival, but the
cognitive level among people with dementia did not appear to play a major role