Study finds jobs affect Alzheimer's - 08/10/04

Study finds jobs affect Alzheimer's - 08/10/04: "Study finds jobs affect Alzheimer's
Workers with mentally demanding careers will less likely get disease
By Lee Bowman / Scripps Howard News Service
Study finds jobs affect Alzheimer's

A study finds that those with Alzheimer’s are more likely to have had less mentally demanding careers than people the same age who did not develop the degenerative brain disease.

Researchers at the Case Western Reserve University School of Medicine examined 122 people with Alzheimer’s and 235 people free of the disease, all over age 60. They interviewed those who were disease-free about their job history from their 20s through their 50s, and got the same information from family members of those with the affliction.

Scientists collected information on the type of job and industry, the length of time on the job and the subjects’ most important activities. Mental, physical, social and fine motor skills required of the job were scored using scales developed by the U.S. Department of Labor.

Writing in the journal Neurology, researchers reported today that, over several decades, people with Alzheimer’s had held jobs with lower mental demands than those in the control group.

During the subjects’ 20s, mental demands of the job were about the same for both groups. But those who were free of Alzheimer’s moved on to jobs with greater mental demands when they were in their 30s, 40s and 50s, increasing the demand level by about 33 percent on average across the decades. However, the mental demands for those with Alzheimer’s remained at about the same level later in their working lives.

The researchers also found that those who developed Alzheimer’s had jobs with more physical demands than those in the control group, but there were no differences in the social or motor skills required.

Because education has been found to help protect against Alzheimer’s, the researchers also reshuffled their results while controlling for educational levels. Still, they found that the results didn’t change.

The study wasn’t able to suggest why a more mentally demanding job would affect later risk, but lead author Kathleen Smyth said several theories have been offered.

“It could be that the disease has a very early effect on the individual’s capacity to pursue a mentally challenging occupation,” Smyth said. “Or it could be that higher levels of mental demands result in increased brain cell activity, which may help maintain a ‘reserve’ of brain cells that resist the effects of Alzheimer’s.”

She added that “there’s also the possibility that jobs with higher mental demands require skills that enhance a person’s ability to perform well on tests used to diagnose Alzheimer’s. If this is the case, then the disease may go undetected in these people until the disease is much farther along than in those whose jobs pose lower mental demands.”

Smyth noted that although the team did consider education, it did not factor in the subject’s social or economic status. Having higher social status and more money generally gives people an advantage in health care and nutrition.

The study also didn’t consider the environmental demands or exposures of the different occupations and their possible contribution to later onset of Alzheimer’s, she said.