The number of people with dementia worldwide is expected to jump from 57 million in 2019 to almost 153 million in 2050, a new study has found.

According to the Global Burden of Disease 2019 Dementia Forecasting study, this expected increase is due to population ageing and population growth.

In order to forecast the prevalence of dementia in the coming  years, the researchers focused on four key risk factors – high body mass index (BMI), high fasting plasma glucose, smoking and education.

They estimated that the number of people with dementia will increase from 57.4 million cases in 2019 to 152.8 million cases in 2050. In 2019, there were estimated to be more women with dementia than men globally and this pattern is expected to continue to 2050.

In 2050, the prevalence of dementia in men globally is forecasted to be 0·5% among those aged 40–69 years, 6·5% among those aged 70–84 years and 23·5% among those aged 85 years and older. In women, the global forecast is projected to be 0·6% among those aged 40–69 years, 8·5% among those aged 70–84 years, and 30·5% (25·0 to 36·8) among those aged 85 years and older.

Worldwide, the smallest percentage changes in the number of projected dementia cases is expected to be in high-income countries in Asia-Pacific (53%) and western Europe (74%). The largest percentage changes are expected to be in north Africa and the Middle East (367%) and eastern sub-Saharan Africa (357%).

“We predicted that population ageing and population growth will drive enormous increases in the number of individuals affected by dementia both regionally and globally. The consequences of these increases are compounded by the high societal and monetary costs of the disease.

“Given the current absence of available effective disease-modifying treatments for dementia, immediate efforts to reduce these projected increases will need to target disease prevention through interventions for modifiable risk factors,” the researchers said.

They noted that previous research suggests that up to 40% of dementia prevalence might be preventable through interventions that target modifiable risk factors.

“This conclusion suggests that large changes in the exposure distributions of modifiable risk factors (i.e, decreases in harmful risk factors and increases in protective factors) have the potential to considerably change our forecasted estimates and reduce the future burden of disease,” they said.

The study, which was led by Emma Nichols of the University of Washington in Seattle, states that these estimates “might be helpful for public health planning efforts”.

“The projected increases in the number of people with dementia, due largely to population growth and population ageing, underscore the crucial need for research focused on the discovery of disease-modifying treatments, effective low-cost interventions and novel modifiable risk factors for the prevention or delay of disease onset,” the researchers said.

This study is published in The Lancet Public Health and can be viewed here.