People live 4.5 years after dementia strikes

People with dementia survive an average four-and-a-half years after diagnosis, researchers said on Friday in a study they hope might help care-givers plan for patients with Alzheimer's and other, similar illnesses.

Researchers know dementia raises the risk of dying early but the study is the first to estimate how long people are likely to survive with the condition, said Carol Brayne, a researcher at the Institute of Public Health at the University of Cambridge.

"This gives people a rough idea of how long they are looking at," said Brayne, who led the study published in the British Medical Journal. "This can add more to the information that physicians and families have."

An estimated 24 million people worldwide have the mental confusion marked by memory loss and problems with orientation that signals Alzheimer's disease and other forms of dementia.

The researchers, who said the number of people with dementia was expected to rise to 81 million globally by 2040, studied 13,000 people aged 65 or older who were assessed for the condition at regular intervals between 1991 to 2005.

During this time, 438 people developed dementia, of whom 81 percent died. Age, gender and disability were the main factors determining how long a person survived, the researchers said.

Women lived for 4.6 years compared to 4.1 years for men. There was nearly seven years difference in survival between the youngest and oldest, with people aged 65 to 69 living 10.7 years and those over 90 living 3.8 years, the researchers found.

"The type of care and the environment where a person is living is also important," Brayne said in a telephone interview.

The study also found that the most frail patients died on average three years sooner than people who are more robust, even with age factored in.

The findings might help policy makers, families and health professionals better plan and care for people with dementia to determine things such as how long a person might be in an institution, the researchers said.

"Some of these results may seem self-evident but they answer questions asked by those caring for and advising people with dementia," the researchers wrote.

"We hope the estimates will be valuable to patients, clinicians, carers, service providers and policy makers."