Demanding careers may thwart Alzheimer’s

People who spend many years in mentally taxing jobs are less likely to develop Alzheimer’s disease than are people who do more-routine work, a report in the Aug. 10 Neurology suggests.

Scientists at Case Western Reserve University School of Medicine and University Hospitals of Cleveland identified 122 people with Alzheimer’s disease and 235 others without it. All were over age 60. The two groups were similar in race, gender, and education level.

Sociologist Kathleen A. Smyth and her colleagues interviewed the people who were free of Alzheimer’s and questioned close relatives of the Alzheimer’s patients. The scientists then rated each person’s career according to its mental demands. They classified the jobs on a scale ranging from multifaceted and creative to repetitious and routine.

The interviews revealed that members of the two groups’ had worked in positions of similar complexity during their 20s. But after age 30, the people without Alzheimer’s had engaged in occupations that were roughly a third more complex than those of the Alzheimer’s patients.

Scientists can only speculate as to why complex work might protect people from Alzheimer’s. Mental activity increases blood flow to the brain, Smyth says, and this might bolster the brain’s defenses against the disease.

She offers two other potential explanations. Perhaps people who had developed strategies for solving mental problems at work could later better perform daily functions such as balancing a checkbook, despite early Alzheimer’s and thereby postpone a diagnosis. On the other hand, people destined to get Alzheimer’s might already be at a slight cognitive disadvantage early in life and so pursue jobs that aren’t mentally demanding, she says.