CHICAGO — A surprising study of elderly people suggests that those who see themselves as self-disciplined, organized achievers have a lower risk for developing Alzheimer's disease than people who are less conscientious.
A purposeful personality may somehow protect the brain, perhaps by increasing neural connections that can act as a reserve against mental decline, said study co-author Robert Wilson of Chicago's Rush University Medical Center.
Astoundingly, the brains of some of the dutiful people in the study were examined after their deaths and were found to have lesions that would meet accepted criteria for Alzheimer's — even though these people had shown no signs of dementia.
"This adds to our knowledge that lifestyle, personality, how we think, feel and behave are very importantly tied up with risk for this terrible illness," Wilson said. "It may suggest new ideas for trying to delay the onset of this illness."
Previous studies have linked social connections and stimulating activities like working puzzles with a lower risk of Alzheimer's. The same researchers reported previously that people who experience more distress and worry about their lives are at a higher risk.
The new findings, appearing in Monday's Archives of General Psychiatry, come from an analysis of personality tests and medical exams of 997 older Catholic priests, nuns and brothers who participated in the Religious Orders Study.
At the start of the study, none of the participants showed signs of dementia. The average age was 75. Everyone took tests, including a standard personality test, then the researchers tracked them for 12 years, testing yearly for cognitive decline and dementia. Brain autopsies were performed on most of those who died.
During the 12 years, 176 people developed Alzheimer's disease. Those with the highest scores for a personality trait called "conscientiousness" at the start of the study had an 89 percent lower risk of developing Alzheimer's compared to people with the lowest scores for that personality trait.
The conscientiousness scores were based on how people rated themselves, on a scale of 0 to 4, on how much they agreed with statements such as: "I work hard to accomplish my goals," "I strive for excellence in everything I do," "I keep my belongings clean and neat" and "I'm pretty good about pacing myself so as to get things done on time."
When the researchers took into account a combination of risk factors, including smoking, inactivity and limited social connections, they still found that the dutiful people had a 54 percent lower risk of Alzheimer's compared to people with the lowest scores for conscientiousness.
Could lower conscientiousness merely be an early sign of Alzheimer's? The researchers think not. At the start of the study, the less conscientious people were no more likely to have lower mental abilities or more memory problems than the most dutiful people in the study.
Renee Goodwin of Columbia University's Mailman School of Public Health was not involved in the new study but has done similar work that found a connection between conscientiousness and better health.
"It's having self-discipline and energy, doing the healthy things," Goodwin said.
Because priests and nuns are an unusual group, the findings may not apply to the general population, Goodwin said, but she noted that there was a normal range of personality types among the participants.
The research may lead to strategies for developing dutiful personality traits as a way to prevent dementia, Goodwin said.
The study was supported by grants from the National Institute on Aging.