Complex Jobs May Help Protect Brain Function

Megan Brooks

November 24, 2014

People who have complex jobs that require working with data, such as architects and engineers, or with other people, such as social workers and lawyers, may have better memory and thinking abilities in later life than their peers in less complex jobs, a new study hints.

"When we look at the association between complexity of work with people or data, we see that those in more complex jobs generally do better on a range of cognitive ability measures," Alan J. Gow, PhD, from Heriot-Watt University and the Center for Cognitive Aging and Cognitive Epidemiology in Edinburgh, Scotland, told Medscape Medical News.

"These results suggest that more stimulating work environments may help people retain their thinking skills, and that this might be observed years after they have retired," he said.

The study was published online November 19 in Neurology.

The researchers examined associations between complexity of main lifetime occupation and cognitive performance in later life in 534 men and 532 women participating in the Lothian Birth Cohort 1936, a longitudinal study of aging. Through use of the Dictionary of Occupational Titles, participants were assigned scores summarizing the occupational complexity of their work with data, people, and things.

General linear model analyses showed that complexity of work with people and data were associated with better cognitive performance at age 70 years after accounting for IQ at age 11, years of education, and social deprivation, the researchers report.

Examples of jobs that score highly for the complexity of work with people are lawyer, social worker, surgeon, and probation officer. Jobs that have lower scores for complexity of work with people include factory worker, bookbinder, painter, and carpet layer.

Jobs that score highly for the complexity of work with data are architect, civil engineer, graphic designer, and musician, while those that score lower for complexity of work with data include construction worker, telephone operator, and food server.

An "Interesting Twist"

Overall, the effect of occupation was small, accounting for about 1% to 2% of the variance between people with jobs of high and low complexity, which is similar to other factors, such as the association between not smoking and better thinking skills in later life, the researchers say.

Dr Gow said the finding that more complex work environments might help protect memory and thinking as people age is "not necessarily surprising" but this study adds an "interesting twist."

"We had data on our participants' cognitive ability in childhood and we know that people who have higher cognitive ability to begin with are those more likely to have more complex jobs. Once we account for that, the association between more complex jobs and better cognitive outcomes is reduced, but there remains a small additional benefit for our cognitive abilities from being in more complex jobs," Dr Gow explained.

Reached for comment on the study, Susan M. Landau, PhD, from the University of California, Berkeley, who wasn't involved in the study, told Medscape Medical News, "There are few studies that measure both childhood data and late-life outcomes on the same people. So an exciting feature of this study is that late-life cognitive function was related to occupational complexity, even after accounting for important early-life factors (childhood cognitive function, education, and deprivation) that are likely to influence late-life abilities."

"As the authors noted, after accounting for childhood factors, the association between occupation complexity and late-life cognition was small (accounting for just a couple percent of variance) and causality cannot be established — both important caveats. But an individual's occupation does account for a substantial portion of adult life, and may in turn be linked to other social and recreational opportunities, so it seems plausible that occupation could indeed lead to later-life advantages or disadvantages in cognitive function," Dr Landau said.

Glen R. Finney, MD, assistant professor, neurology, and co-director, Memory and Cognitive Disorders Program, University of Florida, Gainesville, and a spokesperson for the American Academy of Neurology, said, "This is one of the first studies to highlight the importance of work as a form of 'cognitive reserve' and in that way it's a very interesting study."

"It reinforces the idea that people who are living rich complex intellectual lives are the ones who are usually going to be the best off in old age in terms of avoiding the ravages of Alzheimer's and other dementias," Dr Finney said.

The study was supported by Age UK, as part of a wider research program called the Disconnected Mind, with additional support from the Medical Research Council and the Biotechnology and Biological Sciences Research Council. The authors have disclosed no relevant financial relationships.

Neurology. Published online November 19, 2014. Abstract


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