In particular, experts predict dementia cases will skyrocket in the Middle East, North Africa and eastern sub-Saharan Africa by 2050.
The forecasts include an expected 6.8 million cases brought on by smoking, high blood sugar and a high body mass index (BMI).
But there is a silver lining: better education and healthier lifestyle choices are predicted to decrease global dementia prevalence by 6.2 million cases.
Dr Maria C. Carrillo, Alzheimer’s Association chief science officer, said: “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 ageing of the population.
“In addition, obesity, diabetes and sedentary lifestyles in younger people are rising quickly, and these are risk factors for dementia.”