Mentally demanding jobs may lower dementia risk

GETTING an education is important for a lot of reasons, but there might be one reason you haven’t heard - it could lower your risk of dementia later in life. Decades of research have supported this claim, with one study showing that each additional year of formal education lowers the risk of Alzheimer’s disease or other types of dementia by 7 percent.

Now, a growing body of evidence suggests that the jobs we hold throughout our lives may matter just as much or more than years of education. Having a job that involves high levels of decision-making or creativity, rather than repetitive or manual tasks, could help keep the mind sharp and active.

“Many studies suggest that, if people are working in complex jobs during their lifetime, they have a lower likelihood of developing dementia in later life,” said Jinshil Hyun, assistant professor of neurology at Albert Einstein College of Medicine.

Roles like managers, teachers, lawyers and doctors are considered high complexity jobs, while clerical, transportation and assembly line work have lower complexity. The findings are consistent with the idea that taking part in mentally stimulating activities throughout the lifespan can help preserve late-life brain health and boost cognitive reserve - the brain’s ability to cope with age- or disease-related changes.

But don’t worry if your job doesn’t meet the criteria - there are other things that you can do to improve your cognitive reserve, such as reading, socializing and volunteering.

Why work might be linked to dementia risk

“We spend most of our day in work, at least eight hours a day. So that’s like, a third of our time engaged in work, sometimes more,” said Naaheed Mukadam, professor of psychiatry at University College London. “That’s a large part of what our brain is engaged in and therefore will have a large contributory effect on cognitive reserve development.”

In a recent study, Mukadam and her colleagues investigated which factors could be influencing education’s protective effect against dementia. Their analysis included 384,284 participants and took note of health behaviors like drinking, smoking and exercise; medical conditions like hypertension and diabetes; occupational complexity; and income. The results uncovered that occupational complexity is actually the biggest reason more education tends to lower your risk of dementia, accounting for more than 70 percent of that link.

“We found that occupational complexity explained the biggest proportion of that relationship between education and dementia,” she said. “People who have more education tend to get into better paid, more complex jobs. Then, the benefits for their physical and cognitive health compound in that way.”

Multiple studies have found that those with higher income have a lower risk of dementia, and the researchers speculate that job complexity likely plays a major role in that relationship as well.

Similarly, Hyun and her colleagues found in a 2021 study that occupational complexity is predictive of later-life dementia, independent of education. They looked at the effects on dementia-free survival time, or how many years a person lived before being diagnosed with dementia, in 10,195 participants from six countries. As expected, high school graduates had a 26 percent increase in dementia-free survival time compared with people who completed only middle school or less.

After controlling for education, high occupational complexity, compared with low occupational complexity, was associated with a 19 percent increase in dementia-free survival time. Hyun speculates that the greater mental stimulation of a complex job builds cognitive reserve, which helps people resist cognitive decline and stay mentally sharp for longer, even in the presence of harmful plaques seen in Alzheimer’s-affected brains.

“The cognitive reserve hypothesis suggests that, if people are doing cognitively enriching activities, then their brain has a more efficient network,” Hyun said. “Even if they have a significant amount of pathology in their brain, they have other pathways so that different parts of the brain can still communicate with each other.”

What do to if your job isn’t particularly complex

There are several other ways to strengthen your cognitive reserve other than your occupation:

• Embrace lifelong learning. “Education increases cognitive reserve, like building a muscle,” Mukadam said. Aside from reading regularly, look for classes offered by your local parks and recreation department or community college.

• Pursue enriching hobbies. Some leisure activities - for instance, playing board games and craft activities such as knitting and quilting - have benefits for the brain.

• Find volunteer opportunities. Having a sense of purpose may help preserve cognitive function as we age, according to a recent study. Giving your time to a worthy cause can solidify that sense of purpose, as well as teach new skills and broaden your social network.

• Stay socially connected. Strong social connections are linked to greater cognitive reserve.

• Keep your brain engaged even after you retire. You might think that given the protective role of complex work, retirement may accelerate the rate of cognitive decline. At this point, that’s a hypothesis that some studies have tested, with mixed results. If your job is a source of enjoyment and not stress, Hyun advises against early retirement. “Retiring later may protect your cognitive health longer,” she said.

“Cardiovascular health has been a concern for many, many decades, so it’s great that people are now interested in what they can do for brain health,” said Mukadam. “As we’re living longer, it’s important to preserve that brain function so we can continue to use our brains as long as possible.”