Purpose in Life May Delay Adverse Health Outcomes in Old Age

Objective: Test the hypothesis that a higher level of purpose in life is associated with an older age of Alzheimer's dementia onset and later mortality. Design: Prospective cohort studies of aging and Alzheimer's dementia. Setting: Community-based. Participants: Two thousand five hundred fifty-eight older adults initially free of dementia underwent assessments of purpose in life and detailed annual clinical evaluations to document incident Alzheimer's dementia and mortality. General accelerated failure time models examined the relation of baseline purpose in life with age at Alzheimer's dementia diagnosis and mortality. Exposures: Purpose in life was assessed at baseline. Main Outcomes: Alzheimer's dementia diagnosis was documented annually based on detailed clinical evaluations and mortality was documented via regular contacts and annual evaluations. Results: During a mean of 689 years of follow-up, 520 individuals were diagnosed with incident Alzheimer's dementia at a mean age of 88 (SD = 67; range: 64.1-1065). They had a mean baseline level of purpose in life of 3.7 (SD = 0.47; range: 1-5). A higher level of purpose in life was associated with a considerably later age of dementia onset (estimate = 0.044; 95% CI: 0.023, 0.065); specifically, individuals with high purpose (90th percentile) developed Alzheimer's dementia at a mean age of about 95 compared to a mean age of about 89 for individuals with low purpose (10th percentile). Further, the estimated mean age of death was about 89 for individuals with high purpose compared to 85 for those with low purpose. Results persisted after controlling for sex and education. Conclusion and relevance: Purpose in life delays dementia onset and mortality by several years. Interventions to increase purpose in life among older persons may increase healthspan and offer considerable public health benefit.