Positive trends in global education access are expected to decrease dementia prevalence worldwide by 6.2 million cases by the year 2050. Meanwhile, anticipated trends in smoking, high body mass index and high blood sugar are predicted to increase prevalence by nearly the same number: 6.8 million cases. Both according to new global prevalence data reported at the Alzheimer's Association International Conference® (AAIC®) 2021 in Denver and virtually.
With these forecasts incorporated, researchers with the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine reported at AAIC 2021 that they estimate the number of people with dementia will nearly triple to more than 152 million by 2050. The highest increase in prevalence is projected to be in eastern sub-Saharan Africa, North Africa and the Middle East.
"Improvements in lifestyle in adults in developed countries and other places — including increasing access to education and greater attention to heart health issues — have reduced incidence in recent years, but total numbers with dementia are still going up because of the aging of the population," said Maria C. Carrillo, Ph.D., Alzheimer's Association chief science officer. "In addition, obesity, diabetes and sedentary lifestyles in younger people are rising quickly, and these are risk factors for dementia."
The U.S. National Institute on Aging estimates people over the age of 65 will make up 16% of the world's population by 2050 — up from 8% in 2010.
Also reported at AAIC 2021 were two other prevalence/incidence studies. Key findings include:
Each year, an estimated 10 in every 100,000 individuals develop dementia with early onset (prior to age 65). This corresponds to 350,000 new cases of early onset dementia per year, globally.
From 1999 to 2019, the U.S. mortality rate from Alzheimer's in the overall population significantly increased from 16 to 30 deaths per 100,000, an 88% increase.
Among all areas of the U.S., mortality rates for Alzheimer's were highest in rural areas in the East South-Central region of the U.S., where the death rate from Alzheimer's is 274 per 100,000 in those over 65.
Global Prevalence of Dementia Expected to Grow Rapidly through 2050
To more accurately forecast global dementia prevalence and produce country-level estimates, Emma Nichols, MPH, a researcher with the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine, and colleagues leveraged data from 1999 to 2019 from the Global Burden of Disease (GBD) study, a comprehensive set of estimates of health trends worldwide. This study also aimed to improve on prior forecasts by incorporating information on trends in dementia risk factors.
Nichols and team found dementia would increase from an estimated 57.4 (50.4 to 65.1) million cases globally in 2019 to an estimated 152.8 (130.8 to 175.6) million cases in 2050. The highest increases were observed in eastern sub-Saharan Africa, North Africa and the Middle East. Their analysis suggested that projected increases in cases could largely be attributed to population growth and aging, although the relative importance of these two factors varied by world region.
What's more, Nichols and team forecasted dementia prevalence attributable to smoking, high body mass index (BMI) and high fasting plasma glucose using the expected relationship between these risk factors and dementia prevalence. They found an increase of 6.8 million dementia cases globally between 2019 and 2050 due specifically to expected changes in these risk factors. Separately and conversely, the researchers found that expected changes in education levels will lead to a decline in dementia prevalence of 6.2 million individuals globally between 2019 and 2050. Taken together, these opposing trends come close to balancing each other out.
"These estimates will allow policymakers and decision makers to better understand the expected increases in the number of individuals with dementia as well as the drivers of these increases in a given geographical setting," said Nichols. "The large anticipated increase in the number of individuals with dementia emphasizes the vital need for research focused on the discovery of disease-modifying treatm...
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