Individuals who report having greater purpose in their lives appear less likely to develop Alzheimer's disease or its precursor, mild cognitive impairment, according to a report in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals.
"Alzheimer's disease is one of the most dreaded consequences of aging, and the identification of modifiable factors associated with the risk of Alzheimer's disease is a top public health priority for the 21st century, particularly given the large and rapidly increasing aging population," the authors write as background information in the article. Relatively few of these risk factors have been identified, but data suggest that some psychological factors -- including conscientiousness, extraversion and neuroticism -- may be associated with Alzheimer's disease risk.
"Purpose in life, the psychological tendency to derive meaning from life's experiences and to possess a sense of intentionality and goal directedness that guides behavior, has long been hypothesized to protect against adverse health outcomes," write Patricia A. Boyle, Ph.D., and colleagues at Rush University Medical Center, Chicago. The researchers assessed this quality in more than 900 community-dwelling older adults without dementia who were participating in the Rush Memory and Aging Project.
Participants' purpose in life was measured by their level of agreement with statements such as, "I feel good when I think of what I have done in the past and what I hope to do in the future" and "I have a sense of direction and purpose in life." After an average of four years and a maximum of seven years of annual follow-up clinical evaluations, 155 of 951 participants (16.3 percent) developed Alzheimer's disease. After controlling for other related variables, greater purpose in life was associated with a substantially reduced risk of developing Alzheimer's disease, as well as a reduced risk of mild cognitive impairment and a slower rate of cognitive decline.
Specifically, individuals with a score of 4.2 out of 5 (90th percentile) on the purpose in life measure were approximately 2.4 times more likely to remain free of Alzheimer's disease than individuals with a score of 3.0 (10th percentile).
The biological basis of the association is unknown, but may result from the positive effects purpose of life is reported to have on immune function and blood vessel health, the authors suggest.
The result may have public health implications. "In particular, these findings may provide a new treatment target for interventions aimed at enhancing health and well-being in older adults. Purpose in life is a potentially modifiable factor that may be increased via specific behavioral strategies that help older persons identify personally meaningful activities and engage in goal-directed behaviors," the authors continue. "Even small behavioral modifications ultimately may translate into an increased sense of intentionality, usefulness and relevance."
This work was supported by grants from the National Institute on Aging, by the Illinois Department of Public Health and by the Robert C. Borwell Endowment Fund.
- Patricia A. Boyle; Aron S. Buchman; Lisa L. Barnes; David A. Bennett. Effect of a Purpose in Life on Risk of Incident Alzheimer Disease and Mild Cognitive Impairment in Community-Dwelling Older Persons. Arch Gen Psychiatry, 2010; 67 (3): 304-310 [link]
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