The projections, presented Monday at an international Alzheimer's conference in Stockholm, are slightly higher than those conducted 10 years ago, mostly because more people are expected to live beyond the age of 85 than were predicted to a decade ago.
Ten years ago, Dr. Denis Evans of the Rush Institute on Health Aging in Chicago used figures from the 1990 U.S. Census to estimate that 14 million Americans could be struck by Alzheimer's by 2050.
Now he has updated that projection with information from the 2000 U.S. Census. The latest study is a collaboration between Evan's team, other Chicago researchers and the U.S. Centers for Disease Control and Prevention.
The forecast presented at the International Conference on Alzheimer's Disease and Related Disorders was based on a study of 6,158 people in Chicago and gives a low, medium and high estimate of how many people will probably have the disease within the next 50 years.
The estimate ranges from 11 million people on the low end to 16 million on the upper end. Unsurprisingly, the biggest surge will be among people aged 85 and older, Evans said.
Death rates in the United States have been declining, Evans said, and experts predict they will be half what they are now in 2050.
"The projected increase in numbers of people with Alzheimer's disease is not due only to the total number of people alive, but to the substantially increased survival of people with the disease," said Evans.
Last year, the World Health Organization estimated there may be as many as 37 million people worldwide with dementia. Alzheimer's is the most common form of dementia.
Economists estimate that, in the United States alone, it costs at least $100 billion a year to look after people with Alzheimer's. A study last month estimated that U.S. businesses lose about $61 billion a year because of employees who have to care with family members stricken with Alzheimer's.
"The study on Alzheimer's prevalence and those on the costs related to Alzheimer's underscore the urgent need for more research into the causes, prevention and treatment of this devastating disease," said Stephen McConnell, interim president and chief executive officer of the Alzheimer's Association who was not involved in the research.
He said the projections provide further evidence of a looming global crisis and that his organization is urging the U.S. Congress to increase federal funding of Alzheimer's research to $1 billion a year.
"We must find the answers before these projections become a reality," McConnell said.