Mentally stimulating work plays key role in staving off dementia, study finds

Teaching and lecturing are among the most mentally demanding professions, according to the researchers. Photograph: MBI/Alamy

If work is a constant flurry of mind-straining challenges, bursts of creativity and delicate negotiations to keep the troops happy, consider yourself lucky.

Researchers have found that the more people use their brains at work, the better they seem to be protected against thinking and memory problems that come with older age.

In a study of more than 7,000 Norwegians in 305 occupations, those who held the least mentally demanding jobs had a 66% greater risk of mild cognitive impairment, and a 31% greater risk of dementia, after the age of 70 compared with those in the most mentally taxing roles.

“It really shows how important work is,” said Dr Trine Edwin, a geriatrician and postdoctoral fellow at Oslo university hospital. “It’s important to go to work and use your brain, and to use your brain to learn new things.”

Edwin and her colleagues examined the cognitive complexity of various jobs based on the amount of routine manual and mental work, and the degree of analytical and interpersonal tasks, they involved.

Most people worked jobs with similar degrees of cognitive demands throughout their 30s, 40s, 50s and 60s, meaning that those who started work in less mentally stimulating jobs tended to remain in them, as did those who took on cognitively challenging positions from the off.

After the age of 70, the volunteers took part in standard memory and thinking tests and were classified as having either no cognitive impairment, mild cognitive impairment or dementia. Of those who had worked in the least cognitively challenging jobs, 42% were diagnosed with mild cognitive impairment, compared with only 27% who had worked in the most cognitively stimulating roles.

Among the jobs ranked as most stimulating were teachers and university lecturers, according to the study, in Neurology. Some of the least cognitively demanding jobs were those that involved repetitive manual tasks, such as road work, cleaning and delivering the post.

Previous studies have shown that education has a significant protective effect against cognitive decline in old age. Part of the reason is that better educated people are more likely, and more able, to lead healthier lives. But education also appears to build “cognitive reserve” – the capacity to improvise and find alternative ways of doing things – which may help stave off mental decline, much as physical exercise delays frailty.

According to Trine, higher levels of education accounted for about 60% of the protective effect seen among people who did mentally stimulating jobs. “It means that education is very important, but it’s also what you do afterwards: it’s how you use your brain when you are working. You are building your cognitive reserve at work by being cognitively active,” she said.

The results suggest that people who spend their working lives in less mentally stimulating jobs might benefit from further education and pursuing more cognitively challenging pastimes outside work. “It’s not that you are doomed or you are not – we can empower people for their later cognitive health with education and tasks that are cognitively stimulating,” Trine said.

Prof Gill Livingston, professor of the psychiatry of older people at University College London, said the findings were in line with other studies on the impact of work. “It is not just that more educated people do more cognitively stimulating jobs – they do – but cognitive stimulation in work through problem solving and new situations has an effect by itself.

“This is a lot of cognitive stimulation, as most people work many hours for many years,” she said. But work may not have as big an impact as education, she added, because the brains of children and young adults may change more than those in adults to increase cognitive reserve.