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 healthier ones.
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 First.
"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 cognitive decline."
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.