People who developed Alzheimer's disease tended to have less mentally challenging jobs during their lives than those who did not develop the disease, new research contends.
But the link between developing dementia and career choice is a tough one to sort out, admitted the authors of the study, which appears in the Aug. 10 issue of Neurology.
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"We're really not completely sure what accounts for the linkage that we found," said study author Kathleen Smyth, a sociologist with Case Western Reserve University School of Medicine and University Hospitals of Cleveland.
Notably, the study authors could not control for socioeconomic status.
How the study was conducted
Smyth and her colleagues collected job information, including type of job and industry, length of time on the job and activities within the job position, on 122 people with Alzheimer's and 235 people without the disease. All were over 60.
The jobs ranged a full gamut, including physicists and physicians, computer analysts and surveyors, designers and buyers, mechanics and barbers, tellers and cooks, and hotel clerks, machine operators, stevedores and parking lot attendants.
The occupational history covered the participants' lives from their 20s to their 50s. The control group members were interviewed directly, while surrogates (for example, a spouse or a child) provided information for the Alzheimer's patients. Then, using measures developed by the US Department of Labor, the authors assessed the mental, physical, social and fine motor skill demands of the jobs held by all.
Mental demands lower, physical demands higher
From all this, the researchers concluded that the mental demands of jobs were lower and the physical demands higher for people with Alzheimer's.
According to the findings, those with Alzheimer's tended to have jobs as janitors, construction labourers and sales clerks rather than being engineers, teachers and statisticians, for example, the authors said.
The mental differences were found in all decades except the 20s, while the physical differences were found in all decades but their 30s. There were no differences in social and motor demands.
A few possible explanations
A number of theories could explain the differences, Smyth said. It could be that very subtle symptoms of the disease affected a person's ability to find or keep a mentally challenging job. Or it could be that the mental rigours actually had a protective effect, she added.
The results could also be due to an inherent weakness in the tests used, said one expert.
"Highly educated people do better on testing," said Dr Marshall Keilson, director of neurology at Maimonides Medical Center in New York City.
Then, again, there is the issue of socioeconomic status. Variations in income, access to health care, nutrition and other factors that are related to socioeconomic status could partially explain the findings.
Lifestyle factors play a role
The study does support other data suggesting that certain lifestyle factors can prevent or delay the onset of dementia. The results of a study presented at the recent International Conference on Alzheimer's Disease, for instance, found that older people who undertook leisure activities combining social, mental and physical components, such as gardening, were less likely to develop dementia.
Other than that, the outside experts don't feel the new information adds much to the field.
"They're saying if you're white collar, if you're Martha Stewart by the time you're 20, then, by the time you're 60, if you're not in jail, you won't have Alzheimer's," Keilson said. "Not everyone can choose [their occupation]."
Results are significant, expert says
But Keilson agreed the study points up the value of keeping busy and mentally stimulated.
"It brings up the idea that people who keep busy and keep their minds active don't get or delay getting Alzheimer's," Keilson said. "Don't let the person sit around and vegetate. They have to get out. It's a 'use it or lose it' thing." – (HealthDayNews)
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