Globally, the number of individuals aged 40 years and older living with dementia is estimated to nearly triple by 2050, with its prevalence projected to rise from 57 million cases in 2019 to 153 million cases in 2050, according to a study findings published in  The Lancet Public Health.

Population aging and population growth are key factors behind projected increases in the number of individuals living with dementia. This highlights the critical need for research focused on disease-modifying therapies, effective lost-cost interventions, and novel modifiable risk factors for the prevention of or delay in disease onset. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 study was designed to predict the prevalence of dementia from 2019 to 2050 that is attributable to 3 risk factors: high body mass index (BMI), high fasting plasma glucose, and smoking.

The researchers sought to evaluate the relative contribution of future trends in GBD risk factors, education, population aging, and population growth by performing a decomposition analysis. They used relative risks and forecasted risk factor prevalence to predict GBD risk-attributable prevalence in 2050 globally, as well as by world region and by country.


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The analysis estimated that the number of individuals with dementia would increase from 57.4 million cases (95% uncertainly interval [UI], 50.4 to 65.1) globally in 2019 to 152.8 million cases (95% UI, 130.8 to 175.9) globally in 2050. Notwithstanding large increases in the projected number of individuals living with dementia, age-standardized both-sex prevalence remained stable between 2019 and 2050 (global percentage change, 0.1% (95% UI, –7.5% to 10.8%). According to GBD estimates, in 2019, more women than men had dementia globally (female-to-male ratio, 1.69; 95% UI, 1.64 to 1.73). This pattern was anticipated to continue to 2050 (female-to-male ratio, 1.67; 95% UI, 1.52 to 1.85).

Geographic heterogeneity was observed in projected increases in dementia across countries and regions, with the smallest percentage changes in the number of projected cases of dementia reported in high-income Asia-Pacific (53%; 95% UI, 41% to 67%) and western Europe (74%; 95% UI, 58% to 90%). In contrast, the largest percentage changes in the number of projected cases of dementia were reported in north Africa and the Middle East (367%; 95% UI, 329% to 403%), as well as in eastern sub-Saharan Africa (357%; 95% UI, 323% to 395%).

The projected increases in cases reported in the GBD 2019 study might be attributed largely to population growth and population aging, but the relative importance varied according to world region. Population growth was responsible for most of the increases seen in sub-Saharan Africa, whereas population aging was responsible for most of the increases reported in east Asia.

The researchers concluded that the findings from the GBD 2019 study may be beneficial for public health planning efforts, particularly with respect to “scaling up interventions to address modifiable risk factors and investing in research on biological mechanisms” to meet the needs of individuals with dementia and their caregivers.

Resources should continue to be directed toward improved understanding and characterizing disease mechanisms, with the goal being to develop effective therapeutic agents.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference  

GBD 2019 Dementia Forecasting Collaborators. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Lancet Public Health. Published online January 6, 2022. doi:10.1016/S2468-2667(21)00249-8