A major global analysis projected that the number of people developing dementia each year worldwide will more than double, and in several regions triple, by 2050 unless governments act on preventable risk factors. The findings, highlighted by The Lancet and the Alzheimer's Disease International network, showed the sharpest increases in low- and middle-income countries.

The analysis attributed much of the projected rise to ageing populations, alongside modifiable risks including hypertension, diabetes, obesity, hearing loss, air pollution and physical inactivity. Researchers estimated that addressing these factors could prevent or delay a substantial share of new cases, echoing the 2024 Lancet Commission on dementia prevention.

Alzheimer's Disease International said the burden would fall hardest on health systems in Asia, Africa and Latin America, where diagnostic capacity and specialist care remain scarce. The organisation urged national governments to adopt dementia plans and fund community-based screening rather than rely on expensive hospital treatment.

Global costs of dementia care already exceed $1.3 trillion annually, according to figures cited by the World Health Organization. Analysts projected those costs would climb steeply as case numbers rise, and advocacy groups called for greater investment in both prevention programmes and emerging treatments.

Dr Paola Barbarino, chief executive of Alzheimer's Disease International, said the projections should serve as a call to action. "We cannot treat our way out of this crisis. Prevention, early diagnosis and support for families must be funded now, before the numbers overwhelm every health system on the planet," she said.