More than 26 million people worldwide were estimated to be
living with Alzheimer's
disease in 2006, according to a study led by researchers at
the Bloomberg Johns Hopkins
School of Public Health.
The researchers also concluded that the global
prevalence of Alzheimer's disease will
grow to more than 106 million by 2050. By that time, 43
percent of those with Alzheimer's
disease will need high-level care, equivalent to that of a
nursing home. The findings were
presented June 10 at the Second Alzheimer's Association
International Conference on
Prevention of Dementia, held in Washington, D.C., and are
published in the association's
journal, Alzheimer's & Dementia.
"We face a looming global epidemic of Alzheimer's
disease as the world's population
ages," said the study's lead author, Ron Brookmeyer,
biostatistics and chair of
the Master of Public Health Program at the Bloomberg School.
"By 2050, one in 85 persons
worldwide will have Alzheimer's disease. However, if we can
make even modest advances in
preventing Alzheimer's disease or delay its progression, we
could have a huge global public
According to Brookmeyer and his co-authors,
interventions that could delay the onset of
Alzheimer's disease by as little as one year would reduce
prevalence of the disease by 12
million cases in 2050. A similar delay in both the onset and
progression of the disease would
result in a smaller overall reduction of 9.2 million cases by
2050, because slower disease
progression would mean more people surviving with early-stage
disease symptoms. However,
nearly all of that decline would be attributable to decreases
in those needing costly late-stage
disease treatment in 2050.
The largest increase in the prevalence of Alzheimer's
will occur in Asia, where 48
percent of the world's Alzheimer's cases currently reside.
The number of Alzheimer's cases is
expected to grow in Asia from 12.65 million in 2006 to 62.85
million in 2050; at that time, 59
percent of the world's Alzheimer's cases will live in
To forecast the worldwide prevalence of Alzheimer's
disease, the researchers created a
multistate mathematical computer model using United Nations
population projections and
other data on the incidence and mortality of Alzheimer's.
The research was funded by Elan Pharmaceuticals and
Additional authors of the article "Forecasting the
Global Burden of Alzheimer's Disease"
are Elizabeth Johnson, of Johns Hopkins; Kathryn
Zieger-Graham, of St. Olaf College; and H.
Michael Arrighi, of Elan Pharmaceuticals.