Nearly half of the world's dementia risk is not fixed by fate. In new guidelines published July 15, the World Health Organization estimates that up to 45 percent of dementia cases could be prevented or delayed by addressing modifiable risk factors - a figure that reframes a disease often treated as an unavoidable part of aging [1].
The guidelines, WHO's second edition on the subject, name the levers: tobacco and harmful alcohol use, social isolation, physical inactivity, high blood pressure, diabetes, high cholesterol - and, added since the 2019 edition, air pollution [1]. Dementia affects about 57 million people worldwide, with roughly 10 million new diagnoses a year and an annual cost of about 1.3 trillion dollars, roughly half of it borne as unpaid care by families [1].
The guidelines are as notable for what they do not recommend. WHO explicitly advises against vitamin B, vitamin E, omega-3 supplements, and multivitamins for lowering dementia risk in people without a diagnosed deficiency - the exact products a large 'brain health' supplement industry markets for that purpose [1]. The evidence points to blood pressure and blood sugar, movement and clean air, not to a pill [1].
The record here is a hopeful one, carefully stated: dementia is not fully preventable, and 45 percent is a ceiling, not a promise [1]. What the guidelines establish is that a large share of the risk runs through conditions medicine already knows how to treat - which means the fight against a disease long considered untouchable is, in significant part, the familiar fight against smoking, high blood pressure, diabetes, and dirty air [1].
