| NEW YORK
NEW YORK Mar 5 (Reuters Health) - Nearly half a million
elderly Americans likely died from Alzheimer's disease in 2010,
a figure almost six times higher than previous estimates of
annual deaths, according to a new study released on Wednesday.
The Centers for Disease Control and Prevention has estimated
that approximately 5 million people are living with Alzheimer's
disease in the United States, and that 83,000 die from the
condition each year.
"Many people do not realize that Alzheimer's is a fatal
disease," said lead author Bryan D. James of the Rush
Alzheimer's Disease Center in Chicago.
"Alzheimer's disease starts in the part of your brain that
controls your memory and thinking, but over years it spreads to
the parts of your brain that control more basic functions such
as breathing and swallowing," he told Reuters Health in an
Current national estimates are based on death certificates,
which tend to underestimate deaths from dementia, he and his
colleagues write in the journal Neurology.
They analyzed data from two existing studies that followed
people age 65 and older, starting at a time when they did not
have Alzheimer's. The participants were tracked for an average
of eight years, with annual checkups and brain donation in the
case of death.
One study followed religious orders of nuns and priests and
the other followed people in retirement communities and senior
housing facilities. In all, the studies tracked 2,566 people.
Over the course of the two studies, 559 participants
developed Alzheimer's disease and 1,090 participants died.
People diagnosed with Alzheimer's were more than three times
as likely to die as those without it. The risk was more than
four times as high among participants aged 75 to 84.
Applying these figures to U.S. deaths in 2010, when the data
in the two studies were collected, the authors estimate that
about 500,000 people over age 75 died from Alzheimer's disease
"There's no doubt that if you have Alzheimer's disease, it
increases mortality risk," said Dr. James Leverenz of the
Cleveland Clinic Lou Ruvo Center for Brain Health in Ohio.
But although current national estimates for Alzheimer's
deaths are definitely low, he's not sure the true number is as
high as the one found in this study.
"The two groups are pretty highly educated," said Leverenz,
who was not involved in the new research. "They were in
generally a little bit better health than the general
That means people in these studies could have been less
likely to die from heart disease or other conditions, so a
higher proportion might have died from Alzheimer's, he
One of the reasons it is so hard to estimate the number of
deaths from Alzheimer's is that dementia can be the underlying
reason for a number of more immediate causes of death, Leverenz
said. For instance, severe dementia can lead to problems
swallowing, which leads to malnutrition, which can lead to
pneumonia, the study authors write.
Death certificates tend to list the immediate cause of
death, in this case pneumonia, and leave out dementia.
"Understanding that AD may contribute to almost as many
deaths as the two leading killers in America, heart disease and
cancer, is an eye-opening figure that may convince the public
and policy makers that AD funding should be increased," James
In the study, participants lived an average of four years
after an Alzheimer's diagnosis, but Leverenz said he has seen
patients live with the condition for much longer - 10 or even 20
years for those with an earlier onset of disease.
"The aging of the baby boomer population means more people
living with Alzheimer's disease, which in turn means more people
dying from Alzheimer's disease since no effective treatment or
cure exists," James said.
SOURCE: bit.ly/NwhhyY Neurology, online March 5,
(Editing by Genevra Pittman, Michele Gershberg and Jonathan