A new generation of blood biomarkers is changing how we think about dementia prevention. A recent Lancet article highlighted how Alzheimer-related bloo d markers may detect risk years before symptoms appear [1]. A 2026 Nature Medicine study showed that plasma p-tau217 clocks could estimate the likely timing of symptomatic Alzheimer’s disease several years before onset [2]. This matters because dementia prevention is no longer just about reacting once memory problems begin.

For decades, dementia was framed as the unfortunate but unavoidable consequence of ageing or, for some, genetics. That story is no longer scientifically defensible. Two of the most credible recent population estimates tell a different story: “We estimated that the PAF for all 14 risk factors was 45.3%.” [1] And in England: “Overall, we estimate that up to 34.5% of dementia cases may be preventable.” [2] These figures don’t mean any individual can guarantee they won’t develop