Stronger brain, and probably more interesting too

Since you're reading this, you probably already have an active brain life, but still ...

A new report released last month by the Alzheimer’s Association puts numbers on something most people already feel and maybe even fear:

• First off, 7.4 million Americans are currently living with Alzheimer’s disease. The lifetime risk at age 45 is 1 in 5 for women and 1 in 10 for men.

• Second, in a nationwide survey of more than 3,800 adults ages 40 and older conducted alongside the report, more than two-thirds said they actively worry about developing Alzheimer’s or another dementia. Additionally, 99 percent said they believe maintaining brain health is at least as important as physical health.

• Third, only 9 percent of those surveyed said they actually know a lot about how to maintain brain health.

That gap — nearly universal concern, almost no one knowing what to do about it — is exactly what a new study out of Rush University Medical Center set out to address.

What they studied

Researchers followed 1,939 adults with an average age of 80, none of whom had dementia at the start, for about eight years.

Their goal was to measure something they called “cognitive enrichment” — how mentally stimulating your life has been across an entire lifetime.

They broke it into three stages.

• Early life, before age 18: At this stage they wanted to figure out how often participants had been read to, whether books and newspapers were in their homes, and whether they studied foreign languages for more than five years.

• Middle age, around 40: Here, they looked at income level, access to resources like magazine subscriptions and library cards, and how often participants had visited museums or libraries.

• Later life, around 80: Now, they were looking at the degree to which participants spent their time reading, writing, and playing games, along with retirement income and financial resources.

Each participant got an enrichment score, and then the researchers watched what happened.

The numbers

Over the course of the study, 551 participants developed Alzheimer’s and 719 developed mild cognitive impairment.

However, when the researchers compared the top 10 percent in lifetime enrichment with the bottom 10 percent, the differences were substantial.

Among the most enriched, 21 percent developed Alzheimer’s. Among the least enriched: 34 percent.

After controlling for age, sex, education, and other factors, higher lifetime enrichment was linked to a 38 percent lower risk of Alzheimer’s and a 36 percent lower risk of mild cognitive impairment.

Moreover, among those who did develop cognitive issues, the highest-enrichment group developed Alzheimer’s at an average age of 94. The lowest: 88. For mild cognitive impairment, the gap was 85 versus 78.

Enrichment didn’t eliminate the disease for most people, but it delayed it by five to seven years.

A smaller group of participants underwent autopsies after death.

Among those whose brains showed the physical hallmarks of Alzheimer’s — the amyloid and tau protein buildup — those with higher enrichment had maintained stronger cognitive function and slower decline.

Their brain scans showed damage, but those people had functioned better than the pathology alone would predict. Researchers call this “cognitive reserve.”

What counts

I’ve written about related research here before — the birdwatching study showing that expert birders had measurable structural differences in their brains, the reading study finding that sustained engagement with books improved working memory in older adults, and the research on how loneliness suppresses the brain circuits involved in memory formation.

The Rush study pulls these threads together. It’s not one activity that matters so much as a lifetime pattern of engagement — with ideas, with language, with new information — that appears to build something durable inside the brain.

“Our findings suggest that cognitive health in later life is strongly influenced by lifelong exposure to intellectually stimulating environments,” said lead author Andrea Zammit of Rush University Medical Center.

Reading, learning, and staying curious appear to build something specific and durable inside the brain, something that holds up even when biology starts working against you.

They probably make you a bit more interesting, to boot.

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Other things worth knowing …

• WSJ: Pope Leo XIV warned that artificial intelligence “threatens to normalize an anti-human vision” and said that the concentration of immense digital power in the hands of a few private actors must be countered. The pontiff’s encyclical letter—a text that is poised to define Leo’s papacy—reads like a sharp warning to Silicon Valley executives and humanity more broadly about the future of civilization as new technologies rapidly advance. The risk, he said, is that humans will be reduced “to mere cogs in a system driven toward ever greater efficiency.”

• AP: Also in the same document, Pope Leo made a historic apology for the Holy See’s role in legitimizing slavery and for having failed to condemn it for centuries, calling the Vatican’s record a “wound in Christian memory.” Black American Catholics, activists and scholars have long called for the Holy See to atone for its role in the colonial-era trade in human beings, beyond generic apologies for the involvement of individual Christians.

• ABC News: At Arlington National Cemetery on Memorial Day, Trump honored the 13 service members killed in Operation Epic Fury and used the occasion to criticize his Republican adversaries — singling out Sen. Bill Cassidy, Rep. Thomas Massie, and Sen. Thom Tillis by name. He had kicked off the morning with a Truth Social post wishing a "Happy Memorial Day to all, including the Dumocrats, who disrespect our Military."

• CBS News: Sen. Thom Tillis of North Carolina announced Sunday he will not seek reelection, hours after Trump threatened to back a primary challenger against him for voting against the "big, beautiful bill." A source close to the Trump family told NBC News that Lara Trump is "strongly considering" jumping into the race for his seat.

• CNN: Madonna, Shakira, and BTS will headline the first-ever halftime show in World Cup Final history, on July 19 at MetLife Stadium in New Jersey, curated by Coldplay's Chris Martin. The show will clock in at 11 minutes.

• ScienceDaily: Scientists in Germany demonstrated that ordinary WiFi signals can be used to identify people moving through a room — effectively "seeing" through walls using the same radio waves already blanketing most homes and offices. The technique requires no special hardware beyond a standard router.

• Levi Strauss: Last week I shared the story of the actual inventor of blue jeans, Jacob William Davis, who paired up with Levi Strauss mainly because Davis couldn’t afford a patent filing feel. A few readers asked about the marker supposedly placed at the location of Davis’s 19th century tailor shop in Reno, Nevada. To be honest, I forgot about it until yesterday—but then found that Levis Strauss & Co. actually has a page devoted to it on their website.

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Thanks for reading. I wrote about some of this at Inc.com. See you in the comments.