Although better education and access to health services in developed countries have and will keep reducing the incidence of dementia, the number of people who suffer from it worldwide will triple by 2050, according to new estimates.

New research from the Health Metrics and Evaluation at the University of Washington School of Medicine estimates that the incidence of dementia worldwide will triple by 2050, with most new cases being concentrated in sub-Saharan Africa, North Africa, and the Middle East. Smoking, high body mass index, and high blood sugar will be the leading causes of this rise, it explains, while improved living conditions in developed countries will lower overall incidence in these areas.

All in all, dementia cases by 2050 would reach more than 152 million worldwide, according to the estimates.

Global trends

“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.”

Today, roughly 1 in every 10,000 people worldwide develops early-onset dementia, which is dementia that sets in before the age of 65. This corresponds to roughly 350,000 new cases per year globally. But its effects are not evenly distributed: even in countries such as the US, the mortality rate from Alzheimer’s (the leading cause of dementia) is highest in rural areas compared to the richer, more developed urban centers.

But it’s not a US-only problem. In order to estimate future trends in dementia onset on a country-by-country basis, the team used data from 1999 to 2019 from the Global Burden of Disease (GBD) study, which estimated health trends worldwide and aimed, in part, to improve previous forecasts by incorporating information on trends in dementia risk factors.

According to them, dementia cases will 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. Sub-Saharan Africa, North Africa, and the Middle East will likely see the greatest increases. Overall, however, most of these new cases will come down to population growth and an overall higher average age. Lifestyle factors such as smoking, high body mass index (BMI), and high blood sugar will also increase the prevalence of dementia, to the tune of an estimated 6.8 million cases worldwide by 2050. However, improvements in education levels, healthcare quality, and healthcare access will mostly cancel these out, removing an estimated 6.2 million possible cases.

“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,” Nichols said. “The large anticipated increase in the number of individuals with dementia emphasizes the vital need for research focused on the discovery of disease-modifying treatments and effective low-cost interventions for the prevention or delay of dementia onset.”

“Without effective treatments to stop, slow or prevent Alzheimer’s and all dementia, this number will grow beyond 2050 and continue to impact individuals, caregivers, health systems and governments globally,” said Maria C. Carrillo, Ph.D., Alzheimer’s Association chief science officer. “In addition to therapeutics, it’s critical to uncover culturally-tailored interventions that reduce dementia risk through lifestyle factors like education, diet and exercise.”

With lengthening lifespans around the world, the influence of education and healthcare on the incidence of Alzheimer’s and dementia becomes ever-more powerful. The team reports that there is “an increasing discrepancy in Alzheimer’s mortality” between urban and rural areas of the US and, very likely, in other areas of the world. Lower socioeconomic status, higher average levels of chronic disease, limited availability of internet services, and less access to health services (including primary care) account for most of this difference, the team explains.

We can deduce from here that there is also a disparity in incidence between developed and developing countries from similar, if not the same, causes.

The paper “Estimating the global mortality from Alzheimer’s disease and other dementias: A new method and results from the Global Burden of Disease study 2019” has been published in the journal Alzheimer’s & Dementia.