Dementia cases to more than double by 2050

New dementia cases worldwide will more than double by 2050, rising from 11.4 million a year in 2023 to an estimated 24.7 million, according to a peer-reviewed study published in JAMA Neurology. Researchers at the University of New South Wales Sydney analysed data from more than 38,000 individuals across 18 nations and territories to build the projection.

The doubling is demography, not medicine. The study found incidence rates higher among women than men, and higher in middle- and low-income countries than in rich ones. Senior author Perminder Sachdev called the pattern "particularly concerning because these regions are experiencing rapid population ageing while often having the fewest resources for prevention, diagnosis and care." In other words, the growth lands where diagnostic registers are thinnest and the uncertainty around the underlying numbers is greatest.

The projection also arrives as a budget application. Co-author Henry Brodaty framed the finding as "the urgent need to invest in dementia prevention measures," and the university's statement noted that incidence figures "help estimate future demand for diagnoses and clinical care and contribute to preparing preventive measures." The 24.7 million figure is simultaneously an epidemiological estimate and the opening line of a funding claim for geriatric services — the institutions that will treat the projected patients are the ones producing and circulating the projection. Dementia already affects more than 57 million people worldwide, according to the same statement.

The cheap countermeasures are the ones the section's own coverage keeps surfacing. The US Centers for Disease Control and Prevention lists the risk factors as lack of physical activity, alcohol and tobacco use, high blood pressure, uncontrolled diabetes and hearing loss — factors that cost behaviour rather than drugs. A meta-analysis of 4.2 million people across 30 countries, covered here in August, found that self-chosen leisure exercise is associated with lower dementia risk while physical strain in paid work is not; the person who sets their own pace appears protected, the person whose pace is set for them appears worn. A blood-test study published in JAMA Network Open in March added that plasma p-tau217 levels in women predicted dementia up to 25 years before symptoms, with a three-fold higher hazard of all-cause dementia at elevated baseline levels.

The projection's arithmetic follows the age pyramid wherever it tilts. The treatment bill follows the same pyramid — and the study's authors have already done the costing.