People who do these jobs are 40% less likely to end up with cognitive impairment after 70

By Brett Arends

A new study on the risks of cognitive decline looked at 7,000 people in 305 occupations

Time to sign up for that art or cookery class, crack open that book of brain teasers and puzzles or try, once again, to master Italian or German.

New scientific evidence has landed that seems to confirm what many suspected: that with your brain, as with most things, it may well be a case of "use it or lose it."

A new study from Norway, which was released this month, has found that people who had jobs in which they had to use their brains a lot were 40% less likely to end up with cognitive impairment over the age of 70 than those whose jobs relied mostly on routine.

"We examined the demands of various jobs and found that cognitive stimulation at work during different stages in life - during your 30s, 40s, 50s and 60s - was linked to a reduced risk of mild cognitive impairment after the age of 70," said Trine Holt Edwin of Oslo University Hospital, the lead author of the study, in a statement.

"Our findings highlight the value of having a job that requires more complex thinking as a way to possibly maintain memory and thinking in old age," she added.

The research was based on a study of 7,000 people in 305 occupations.

The researchers grouped occupations into four categories, ranging from those that required the most thinking and creativity to those that required the least. For example, teachers were in the first category. Mail-carrier and custodian jobs were in the fourth group.

Even after accounting for variables such as age, gender, education and income, the researchers found that those in the fourth group were 66% more likely to develop cognitive impairment or dementia after the age of 70.

Or, to look at the same numbers the other way around, those in the first group - the one where you have to do a lot of thinking all the time - were 40% less likely to end up cognitively impaired than those in the first.

OK, so we can't conclude that doing crossword puzzles or learning a musical instrument will cut our risks by 40% on its own. That's the maximum gain, realized over decades, seen by those who held stimulating jobs compared with those who held routine or boring jobs.

Exercising your brain

But the research adds to data suggesting that exercising your brain - in other words, thinking a lot, and doing things that challenge you mentally - really is good for it.

This is, perhaps surprisingly, a controversial topic among medical researchers. Many top researchers in the field have lined up on either side of the debate. And it is not hard to find studies that make you wonder if the whole thing is bunk.

One of the major challenges with research in this area comes down to practicality.

That's because there is no way to replicate laboratory conditions in the real world. We can't separate a million pairs of identical twins, lock them up in two different medical institutions for their entire lives, and then, for example, subject only one group to brain training and cognitive stimulation for decades, and see what happens.

Most studies have had to rely on self-reporting, or short-term supervised intervention.

That's what makes this new research out of Norway especially interesting. The study looked at jobs that large numbers of people had held over decades. So the researchers were able to look at the effects of sustained cognitive stimulation and exercise over the long term.

It's not a laboratory, and it's not perfect. But it's a pretty good start.

Meanwhile, it's worth remembering that those in the scientific community who are skeptical of the benefits of mental stimulation for brain health are often trying to answer a different question from the rest of us.

Typically, medical researchers set themselves an extremely high bar for proving something, and then fail to achieve it. They are often quick to point out that they haven't actually proven that A causes B, merely that there is a strong statistical association between A and B.

Fair enough. But in the real world we are concerned with different questions. What are the chances this might help me? And what are the costs and risks?

Many people gave up smoking long before medical researchers had proven conclusively that smoking caused lung cancer. If they'd waited for the proof, many of them would have died first - of lung cancer.

This is no way to operate. Dementia is a terrible affliction - Alzheimer's disease being the most common type of dementia. Anything that plausibly might reduce the risk is worth trying. Especially if it is as engaging as doing crossword puzzles or practicing a musical instrument or learning a new language. All are easier than giving up smoking.

-Brett Arends

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04-27-24 0514ET

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