Working memory: the surprising decline of dementia

July 30, 2026

AI Summary

5 min read

Between 1988 and 2015, the share of older people with dementia fell by 13 percent per decade across six countries in North America and Europe. In the 1980s, three in every ten people in their late 80s had dementia; that rate has now dropped to roughly one in ten. "There has just been this absolutely astonishing decline in the rates of dementia over the past 40 years," says Jonathan Bruzenthal, an international correspondent at The Economist.

The finding is counterintuitive because the single biggest risk factor for dementia is age—risk roughly doubles every five years after the late sixties—and populations are living longer. The baby boom generation is also entering old age in large numbers. Simple arithmetic projecting from those numbers yields astronomical increases, which is why many researchers initially struggled to believe the data. Eric Stallard, a researcher at Duke University, held off publishing his findings for two and a half years while he repeatedly checked for errors.

What is driving the decline

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What you'll learn

1 (01:36) **The Surprising Decline in Dementia Rates** - Jonathan Bruzenthal, an international correspondent at The Economist, introduces the central finding: dementia rates have been falling dramatically over the past 40 years
2 (02:46) **Why the Public Perception Is Wrong** - Many people assume dementia is getting worse, but that's because the raw number of cases rises as populations age, not because the age-adjusted risk is increasing
3 (03:42) **The Million-Dollar Question: What's Behind the Decline?** - The exact biological mechanisms remain unclear, but researchers are moving beyond the amyloid hypothesis
4 (05:08) **Lifestyle Factors from Finnish Research** - A natural experiment in Finland showed that lifestyle changes aimed at reducing heart attacks also dramatically cut dementia rates
5 (06:26) **The Lancet Commission: 45% of Dementia Cases Are Preventable** - The authoritative Lancet Commission on Dementia has identified multiple modifiable risk factors that could prevent or postpone nearly half of all dementia cases
6 (07:42) **The Shingles Vaccine: A Cheap, Powerful Intervention** - One of the most exciting recent findings is that the shingles vaccine reduces dementia risk by 20% over seven years
7 (08:28) **Disappointing Drug Trials and New Hope** - Anti-amyloid drugs have been disappointing, offering only minor cognitive improvement at great cost and risk

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Show Notes

A dive into the data reveals that, despite dire past predictions, the prevalence of dementia is actually waning. We take a look at Pix, a beloved Brazilian digital-payments system, and why it so bothers President Donald Trump. And we attend one of the concerts that reveals how the appeal of emo music is holding strong across generations.

Guests and host:

Jonathan Rosenthal, international correspondent
Carla Subirana, news editor
Sarah Lawrynuik, deputy editor of “The Intelligence”
Jason Palmer, co-host of “The Intelligence”

Topics covered:

dementia, global health statistics, ageing
Brazil, Pix, payment systems, Donald Trump
emo music, My Chemical Romance

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