Julie Andrews is 91 and still working: she voices a character on Bridgerton and has published a new children’s book with her daughter. Asked what keeps her sharp, the actress points to staying busy and creating. Research gives that instinct some backing, since a pooled analysis of more than 100,000 people tied cognitively stimulating jobs to an 18% lower risk of dementia.
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The finding is an association, and it describes groups of people rather than any individual. It still fits a body of work on how mental activity across a lifetime may build resilience against cognitive decline.
The BMJ analysis behind the 18% figure
The 18% comes from a 2021 study in The BMJ, an international team’s pooling of data from more than 100,000 people in the United Kingdom, Europe and the United States. After adjusting for other risk factors, participants whose jobs were cognitively stimulating had an 18% lower risk of dementia than those whose work made fewer mental demands. ScienceAlert’s profile of Andrews pairs that result with her story.
Andrews herself has said that as long as her brain holds out, she is doing fine, and on the podcast Wiser Than Me, recorded at 88, she described feeling like she was in her 50s. Her father was also a lifelong learner who studied a new language at 76, and she credits him for her love of books and writing.
Lifetime enrichment and the Illinois cohort
A 2026 study in the journal Neurology widened the lens from jobs to whole lives. Researchers followed nearly 2,000 older adults in Illinois who did not have dementia at the start. After nearly eight years, 551 had developed Alzheimer’s disease. People who more often read, visited libraries and museums, learned languages or used dictionaries had better outcomes, as the published paper shows.
Higher lifetime cognitive enrichment scores were linked to a 38% lower risk of Alzheimer’s, a 36% lower risk of mild cognitive impairment, and onset of cognitive decline delayed by up to seven years. Co-author Andrea Zammit, a neuropsychologist, said the results suggest that consistently engaging in varied, mentally stimulating activities throughout life may make a difference in cognition.
The idea underneath is cognitive reserve: people who have exercised their brains more over the years may be better buffered against damage, much as a stronger muscle tolerates more strain. The concept helps explain why the Illinois and BMJ results point the same direction even though one measured leisure habits across a lifetime and the other measured the demands of a paid job: both are proxies for how much a brain has been asked to do.
Work itself appears in the Norwegian data too. A 2024 study in Neurology found that people who held cognitively stimulating occupations from their 30s through their 60s had lower risk of mild cognitive impairment and dementia in their 70s. The consistency across countries, the United Kingdom and Europe in The BMJ pooling and Norway here, makes a coincidence less likely, though stimulating jobs also tend to come with more education and higher income, which complicate the comparison.
Learning new skills after retirement
Retirement is a pressure point. A 2023 study in the Journal of the American Geriatrics Society found cognitive function declined at an accelerated rate immediately after retirement, though that too is an association and does not prove that leaving work causes the decline.
Evidence on what helps after work ends comes from Rachel Wu at the University of California, Riverside. Her team found that older adults who learned at least three new skills over three months, such as Spanish, drawing or music composition, improved their cognitive performance to a level on par with a much younger cohort, as the university’s account describes.
Researchers who study so-called super-agers, people who stay sharp into very old age, report a similar theme. Alexandra Touroutoglou of Harvard says such people often enjoy challenging themselves and want to learn new things, a pattern covered in a Harvard Gazette report. Their stories are anecdotal in the same way Andrews’s is, which is why the controlled and large-sample studies carry the weight in this discussion.
The 2024 Lancet Commission estimated that about 45% of dementia cases worldwide could be prevented or delayed through lifestyle, medical or environmental changes. How much of that share belongs to mental stimulation specifically remains an open question, and none of the studies here proves that a busy schedule protects any one person. Andrews, for her part, offers no claim beyond her own experience, and the research supports a modest reading: staying mentally occupied is associated with better odds, and it costs little to try. Reading, learning a language, taking up an instrument or drawing all fit the activities the studies describe, and none requires a clinic visit or a prescription.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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