The World Health Organization has issued new dementia-prevention guidelines stating that up to 45 percent of the risk of cognitive decline and dementia can be prevented or delayed by controlling modifiable factors. The document, released on 15 July, updates the 2019 edition and incorporates two new risk factors—air pollution and untreated vision loss—alongside established targets such as smoking, harmful alcohol use, hypertension, diabetes, obesity, hearing loss and social isolation. With more than 57 million people living with dementia globally and nearly 10 million new cases each year, the WHO frames prevention as the most effective strategy in the absence of a cure.

A separate preclinical study published in Cell Death & Disease offers a different angle: instead of attacking amyloid plaques directly, researchers from Spain’s Instituto de Neurociencias and Switzerland’s EPFL reprogrammed microglia, the brain’s resident immune cells, using an experimental molecule called OLE. In animal models of Alzheimer’s, the treatment reduced plaque toxicity, lowered brain inflammation and improved memory performance. The work remains at the animal stage, and the authors stress that safety and efficacy in humans have yet to be evaluated. Meanwhile, findings presented at a recent scientific conference suggest that speaking multiple languages is associated with a younger brain age—up to a 13-year delay for those speaking four languages—though a meta-analysis indicates the effect may delay diagnosis rather than lower the absolute risk of developing dementia.

Evidence on diet reinforces the prevention message. A ten-year study of 10,775 adults, average age 51, published in JAMA Neurology, found that those consuming 28 percent or more of their daily calories from ultra-processed foods faced a higher risk of dementia. Researchers point to increased brain inflammation as a likely mechanism. The finding aligns with broader data on metabolic health: the US National Heart, Lung, and Blood Institute reports that between 2009 and 2020, obesity prevalence among adults aged 20–44 rose from 32.7 percent to 40.9 percent, and diabetes from 3 percent to 4.1 percent, driving a sharp increase in heart-disease risk in young adults. In Indonesia, where the over-60 population has passed 10 percent, inadequate housing and poor sleep quality compound the burden, while digital health platforms are being used by companies to contain rising medical costs projected to hit 15.1 percent inflation in 2026.

Viewed from Geneva, the WHO is urging member states to embed dementia risk reduction into primary care through public education, early detection of risk factors and management of chronic conditions. The next scientific milestones to watch are the progression of the microglia-reprogramming molecule into human trials and the publication of peer-reviewed data on multilingualism and brain-age gap. On the policy side, the inclusion of air pollution as a modifiable risk factor is expected to intensify pressure on governments to tighten emissions standards as a public-health measure.