The number of adults (aged 40 years and older) living with dementia worldwide is expected to nearly triple, from an estimated 57 million in 2019 to 153 million in 2050, due to population growth and population ageing. The Global Burden of Disease study is the first to provide forecasting estimates for 195 countries worldwide, and is published in The Lancet Public Health.
Dementia cases will rise in every country, with the smallest estimated increases in high-income Asia Pacific (53%) and western Europe (74%), and the largest growth in north Africa and the Middle East (367%) and eastern sub-Saharan Africa (357%). Experts project that improved access to education could lead to 6 million fewer cases of dementia worldwide by 2050.
This analysis forecasts dementia prevalence in 195 countries and territories, and examines the impact of expected trends in exposure to four important risk factors—smoking, obesity, high blood sugar, and low education.
The estimated cases of dementia in India in 2019 were 3,843,118. By 2050, the number is expected to increase 197% to 11,422,692 cases.
“We found increases in every country, and in India we estimate that the number of people with dementia will increase by 197% between 2019 and 2050. These increases are due predominantly to population aging and population growth, but trends in the prevalence of risk factors for dementia, such as smoking, obesity, and high blood sugar are also expected to have an effect,” lead author of the study, Dr Emma Nichols from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, USA told The Indian Express via e-mail.
Dementia is currently the seventh leading cause of death worldwide and one of the major causes of disability and dependency among older people globally—with global costs in 2019 estimated at more than US$1 trillion.
Although dementia mainly affects older people, it is not an inevitable consequence of ageing. A Lancet Commission published in 2020 suggested that up to 40% of dementia cases could be prevented or delayed if exposure to 12 known risk factors were eliminated—low education, high blood pressure, hearing impairment, smoking, midlife obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, head injury, and air pollution.
“These results should act as a call to action for governments and decision-makers, who should scale up needed support and services for the larger number of individuals anticipated to have dementia and their caregivers in the future. Policy-makers should also invest in scaling up interventions targeting modifiable risk factors and research on potential disease-modifying drugs to stop or slow the progression of disease,” Dr Nichols said.
The study predicts that the greatest increase in prevalence will occur in eastern sub-Saharan Africa, where the number of people living with dementia is expected to climb by 357%, from nearly 6,60,000 in 2019 to more than 3 million in 2050, mainly driven by population growth.
By contrast, the smallest increase is projected in high-income Asia Pacific, where the number of cases is expected to grow by 53%, from 4.8 million in 2019 to 7.4 million in 2050—with a particularly small increase in Japan (27%). In this region, the risk of dementia for each age group is expected to fall, suggesting that preventive measures, including improvements in education and healthy lifestyles, are having an impact.
Globally, more women are affected by dementia than men. In 2019, women with dementia outnumbered men with dementia 100 to 69. And this pattern is expected to remain in 2050. “It’s not just because women tend to live longer,” says co-author Dr Jaimie Steinmetz from IHME, University of Washington, USA. “There is evidence of sex differences in the biological mechanisms that underlie dementia. It’s been suggested that Alzheimer’s disease may spread differently in the brains of women than in men, and several genetic risk factors seem related to the disease risk by sex.”