FRIDAY, May 9 (HealthDay News) -- Having an intellectually demanding job that nurtures thinking abilities may result in better cognitive abilities during retirement, regardless of intelligence, education level or age, a Duke University Medical Center study suggests.

"Our society is expected to live and work longer than previous generations, so we sought to understand how an individual's occupation affected cognition later in life," study author Guy Potter, an assistant professor of psychiatry, said in a prepared statement.

The study included 1,036 male twins who were given a test to determine their general learning abilities when they joined the U.S. military in the early 1940s. The participants had follow-up assessments of their cognitive status every three or four years after they were in their 60s.

The Duke researchers found that cognitive benefits associated with intellectually demanding jobs were greatest among people who had lower scores on intelligence tests in their youth, while physically demanding work was associated with a decrease in cognitive performance later in life.

The study was published in the May issue of Neurology.

"Although the intellectual and physical demands of an individual's job are not the largest factors influencing cognitive performance as we age, this study illustrates how a number of smaller influences like these can accumulate over the life span to have a positive or negative effect on brain health in later life," Potter said. "Unlike age or intellect, job demands are something that an individual can potentially modify to optimize their cognitive reserve."

"Most of us spend a significant portion of our adult life at work, and we may actually be benefiting from the intellectual demands placed upon us," he added.

Potter and his colleagues made special mention about the finding that manual labor may be associated with poorer cognitive performance later in life.

"Physical exertion has health benefits in its own right. It is important for people to find a place for both mental and physical activity in their lives, and for researchers to offer insights about how this can best be achieved," Potter said.

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