The number of Americans with some form of Alzheimer's disease is projected to more than double by 2060, increasing from an estimated 6.08 million today to about 15 million, according to a study in Alzheimer's and Dementia.
For the study, researchers from the University of California-Los Angeles Fielding School of Public Health looked at data from previous epidemiologic studies and used a forward calculation method to estimate how many Americans would have some form of Alzheimer's by the year 2060. The researchers accounted for eight pre-clinical and clinical stages of Alzheimer's, as well as deaths from the disease.
According to Medscape, the researchers also assessed the ramifications of two possible types of disease-modifying preventive interventions: primary prevention, which occurs prior to evidence of brain pathology, and secondary prevention, which aims to slow progression of the disease from "mild cognitive impairment" (MCI), an early form of Alzheimer's, to full Alzheimer's.
The researchers estimated that the number of Americans with any clinical form of Alzheimer's will increase from 6.08 million in 2017 to 15 million in 2060. Specifically, they projected that the number of Americans with:
- Clinical Alzheimer's will increase from 3.65 million in 2017—of whom an estimated 1.54 million, or 42%, had late clinical Alzheimer's disease, requiring nursing-home-level care—to 9.3 million in 2060;
- MCI will increase from 2.43 million in 2017 to 5.7 million in 2060;
- Preclinical Alzheimer's will increase from 46.7 million to 75.68 million in 2060.
These numbers, according to the researchers, underscore the importance of developing techniques to prevent Alzheimer's. A hypothetical primary prevention strategy that halved the annual risk of developing amyloidosis, which the researchers said is a sign of preclinical Alzheimer's, would cut the prevalence of MCI and Alzheimer's by 0.69 million and 2.35 million in 2060.
Meanwhile, a hypothetical secondary prevention strategy that halved the annual risk of progression to MCI would in 2060 cut the prevalence of MCI by 2.14 million and Alzheimer's by 3.84 million, the researchers found.
Ron Brookmeyer, a professor of biostatistics at UCLA and the lead author on the study, said that the main driver of the expected increase is "the age structure of our population. We're getting older, and that profile is going to see a lot more Alzheimer's disease."
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Brookmeyer cautioned that while nearly 47 million people currently have some form of preclinical Alzheimer's, that doesn't necessarily mean they will actually develop the disease. "Only a fraction of them would," he said. "The natural (progression) of this disease is very long and it takes decades. Many people's natural lifespans will not be long enough for the disease to progress to the point where they actually experience dementia."
Further, Brookmeyer said preventive strategies can be implemented during those decades. "Slowing disease progression may not be a cure or magic bullet," he said, "but may be adequate to have huge public health impact, because if you can slow disease progression, the natural lifespan of individuals may not be long enough for them to develop clinical disease."
He continued, "We need to develop interventions that work all along the continuum of the (disease's development)," adding, "It's a tall order, but that's currently where the field is and that's where the research needs to move forward."
Separately, Keith Fargo, director of scientific programs and outreach at the Alzheimer's Association, said the public should not "read too much into the study and feel panic." He explained, "Although these are large numbers and we think of them as alarming, which in some sense they are, most people in preclinical stages will not go on to get [Alzheimer's]" (Swift Yasgur, Medscape, 12/11; Kasulis, Mic, 12/12).
How to deliver cost-effective Alzheimer's care
Over 5.3 million Americans currently suffer from Alzheimer’s disease and related memory disorders and the Alzheimer’s Association predicts this number to triple to 13.8 million by 2050.
To learn more about how leading memory disorders programs are allocating their resources, download our brief Building a Financially Successful Alzheimer’s Disease and Memory Disorders Program.