Effect of a purpose in life on risk of incident Alzheimer disease and mild cognitive impairment in community-dwelling older persons.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study
PubMed 20194831 · doi:10.1001/archgenpsychiatry.2009.208
What was done
In a prospective longitudinal epidemiologic study (Rush Memory and Aging Project), 951 community-dwelling older adults without dementia from senior housing facilities and residences in the Chicago metropolitan area underwent baseline evaluations of purpose in life. Participants completed up to 7 years of annual clinical evaluations (mean follow-up, 4.0 years) to assess incident Alzheimer disease (AD), mild cognitive impairment (MCI), and rate of change in global cognitive function. Proportional hazards models adjusted for age, sex, and education, and subsequently added terms for depressive symptoms, neuroticism, social network size, and number of chronic medical conditions.
What was found
During follow-up, 155 of 951 participants (16.3%) developed AD. In models adjusted for age, sex, and education, greater purpose in life was associated with a reduced risk of AD (hazard ratio [HR], 0.48; 95% CI, 0.33-0.69; P < .001), such that participants at the 90th percentile of purpose (score = 4.2) were approximately 2.4 times more likely to remain free of AD than those at the 10th percentile (score = 3.0). This association persisted after controlling for depressive symptoms, neuroticism, social network size, and chronic medical conditions. Greater purpose in life was also associated with a reduced risk of incident MCI (HR, 0.71; 95% CI, 0.53-0.95; P = .02) and a slower rate of cognitive decline (mean [SE] global cognition estimate, 0.03 [0.01]; P < .01).
Why it matters
These findings suggest that purpose in life is a potent experiential factor longitudinally associated with preserved cognitive health and reduced risk of clinical Alzheimer disease in older adults.
Limits
The observational cohort design cannot establish causality, and reverse causality cannot be fully ruled out if preclinical neurodegenerative changes reduced baseline sense of purpose. Participants were recruited from senior housing and residences within a single metropolitan area, which may limit generalizability.
Cited by
- supports Having a strong sense of purpose in life makes individuals more resilient to cognitive decline over time.