Global burden of Alzheimer’s projected to triple

Photo by Fred Kearney via Unsplash.

Cases of Alzheimer’s disease are rising throughout the world and could triple by 2050, according to a recent analysis in The Lancet. While much of this increase can be traced back to the fact that we’re living longer, researchers also concluded that three key modifiable risk factors — smoking, high body mass index and diabetes —  also contribute to the increased burden and could cost health systems around the world billions in long-term services and supports.

The number of people with Alzheimer’s disease is also increasing in the U.S. and other high-income nations thanks to increased life expectancy. By 2050, cases of Alzheimer’s in those 65 and older could top 12.7 million in the U.S. alone. The ratehowever, will actually decline slightly, because of the sheer size of this demographic. And can be explained largely by educational changes, according to Eileen Crimmins, Ph.D., chair in gerontology at the USC Leonard School of Gerontology.

As the search for treatment and a cure for the disease continues, addressing risk factors is one of our only viable tools. Journalists who are following this issue have an opportunity to report on other potentially fruitful research you may have missed, as well as look at how health systems in the U.S. and around the world are planning to address this looming crisis. There are also new opportunities to look into COVID-19’s effects on the brain and whether we will see more cases of dementia in the future. We also recently reported on continuing disparities in care among Blacks, Hispanics, Asian Americans and Native Americans, who continue to have a higher burden of illness and lower access to care compared with whites.

Global burden of disease rising

Researchers with the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine used 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 prior forecasts by incorporating information on trends in dementia risk factors.

The researchers found that 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.

“The increase in prevalence seen in less developed countries is mainly because of living longer and living better and that is the dominant factor,” said Scott Small, M.D., director of the Alzheimer’s Disease Research Center and professor of neurology at Columbia University, who was not involved in the study.

Researchers also predicted dementia prevalence due to smoking, high body mass index 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 because of expected changes in these risk factors. However, at the same time, projected changes in education levels will lead to a decline in dementia in certain regions.

“It’s easier for some of us than others, but it’s factually true — exercise, don’t develop diabetes, maintain good cardiovascular health,” said Small.

Improving overall health almost presents a conundrum, according to Crimmins. By controlling risk factors such as obesity and heart disease, life expectancy will increase. And since the risk of Alzheimer’s increases with age, more people may ultimately end up with the disease. “The only way to really reduce this disease is to actually treat this disease or prevent this disease,” she said.

In the U.S., there is an increasing difference in mortality rates among urban and rural populations. This discrepancy is likely the result of many health disparities experienced by rural residents compared to their urban counterparts, including lower socio-economic status, higher levels of chronic disease, limited availability of internet services, and less access to health services including primary care, according to the Alzheimer’s Association.

The Alzheimer’s Association found:

• An estimated 10 in every 100,000 people develop dementia with early-onset (before age 65). This corresponds to 350,000 new cases of early-onset dementia per year, globally.

• From 2000 to 2019, the U.S. mortality rate from Alzheimer’s in the overall population increased by 145%.

• 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.

In 2021, Alzheimer’s and other dementias will cost the U.S. $355 billion, including $239 billion in Medicare and Medicaid payments combined. By 2050, Alzheimer’s is projected to cost more than $1.1 trillion (in 2021 dollars). This includes more than three-fold increases both in government spending under Medicare and Medicaid and in out-of-pocket spending.

“If you put off Alzheimer’s, that’s good. If you extend life, that’s good. But if you are trying to reduce caseloads of Alzheimer’s, that’s not good. We want to extend life, which is the aim, but the outcome is, it costs in other ways,” said Crimmins.

As scientists continue hunting for a viable Alzheimer’s treatment or cure, the study researchers noted that in the interim, policymakers worldwide must plan for the expected increases in the use of health and social care services and to expand resources to support caregivers of people with dementia.

Resources for reporters 

Leave a Reply