People who spent most of their lives in jobs that involve little brain work appear more likely to eventually develop Alzheimer’s disease, according to new study findings released Monday.

However, it remains unclear whether the jobs themselves cause the disease, or if people more prone to the disease are less likely to tackle more mentally challenging careers, the study’s lead author told AMN Health.

“It could be that the effects of (Alzheimer’s disease) start early in life, and may influence people’s ability to get or keep mentally demanding jobs,” Dr. Kathleen A. Smyth explained. “It also could be that being in mentally demanding jobs for many years helps people to do better mentally when they are older.”

For people who have no alternative but to stay in less challenging jobs, Smyth noted that other research shows that people who engage in thought-provoking leisure activities also appear to be protected against Alzheimer’s disease.

“I would recommend things like playing games involving strategy like chess, learning an instrument or a new language, or working crossword puzzles. Trying something new is probably also a good idea. The idea is to do things that actively engage your brain,” said Smyth, who is based at Case Western Reserve University in Cleveland, Ohio.

To investigate whether job history played a role in the development of Alzheimer’s disease, Smyth and her colleagues reviewed the work history of 122 people with the disorder and 235 people who were free of the disease.

Jobs were classified as having high mental demands if they were complex, involved a variety of activities, required creative rather than routine tasks, and workers had some ability to control, direct or plan activities.

Reporting in the journal Neurology, the researchers found that people without Alzheimer’s disease were more likely to have held jobs that required significant brain work, while people with the disease were more likely to have held physically demanding jobs.

“On average, people with Alzheimer’s disease in our study had jobs with lower mental demands than people without Alzheimer’s disease in their 30s, 40s, and 50s - that is, across most of their working lives,” Smyth noted.

She added that the study does not examine whether certain decades of life are more vulnerable to the potential effects of a job that offers little mental stimulation. However, she noted that it may be important to challenge your brain as soon as possible.

“I base this on the idea popular with many scientists that mentally stimulating activities help people build up a ‘reserve’ that helps them to perform better in later life,” Smyth noted. “If this is so, then starting earlier would allow more time for this reserve to be built up.”

SOURCE: Neurology, August 2004.