The population of Americans aged 65 or older in 2014 was 46.2 million, or about 14.5 percent of the population. This number represents an increase from 2000, in which roughly 12.5 percent of the U.S. population was 65 or older, and is in line with the trend that predicts a rise to 21.7 percent by 2040.
Yet, despite the growing size of the U.S. elderly population, fears that dementia rates would rise has been quelled.
According to a study published Nov. 21 in the Journal of the American Medical Association Internal Medicine, dementia rates have fallen between 2000 and 2012. In the year 2000, 11.6 percent of the population aged 65 and older had dementia; only 8.8 percent had the degenerative brain disease in 2012.
The New York Times adds that in 2000, the average age of a dementia diagnosis was 80.7 years old. In 2012, it was 82.4.
“The dementia rate is not immutable,” said Dr. Richard Hodes, director of the National Institute on Aging. “It can change.”
John Haaga, director of the institute’s behavioral and social research division, added that the news means “roughly a million and a half people aged 65 and older who do not have dementia now would have had it if the rate in 2000 had been in place.”
Dementia remains the most expensive disease to treat, costing an estimated $215 billion for 2010. By comparison, heart disease cost an annual estimate of $102 billion, and cancer just $77 billion.
"Rising levels of education among U.S. adults over the past 25 years may also have contributed to decreased dementia risk,” the study’s authors noted, reports NBC News. “The proportion of adults 65 years or older with a high school diploma increased from 55 percent in 1990 to 80 percent in 2010, while the proportion with a college degree increased from 12 percent to 23 percent."
The authors further cautioned: "Although these recent findings indicate that a person's risk of dementia at any given age may be decreasing slightly, it should be noted that the total number of Americans with Alzheimer's and other dementias is expected to continue to increase dramatically."