Life Purpose Lowers Risk for Cognitive Impairment in a United States Population-Based Cohort

We investigated whether sense of purpose in life (PiL) is associated with a lower risk for and delayed onset of developing cognitive impairment in a diverse US population-based cohort.

Participants from the Health and Retirement Study aged 45 or older with normal cognitive performance at baseline and ≥ 2 subsequent objective cognitive assessments were included. Cognitive performance was objectively assessed biennially using the modified Telephone Interview for Cognitive Status (mTICS). Cognitive impairment was defined as having two consecutive visits with mTICS scores below a psychometrically validated threshold consistent with mild cognitive impairment or dementia. PiL was assessed at baseline using a seven-item questionnaire. Cox Proportional Hazards was modelled to examine the association between PiL and cognitive impairment. Restricted Mean Survival Times was calculated to estimate delay in onset age for cognitive impairment.

Of 13,765 participants, 1,820 (13%) developed cognitive impairment during follow-up (median of 8 years and up to 15 years). Those with higher PiL had significantly lower risk for developing cognitive impairment compared to those with lower PiL after adjusting for sex, baseline age, educational attainment, average depressive symptom score, and race/ethnicity (HR = 0.72, 95% CI: [0.63-0.82]). This association remained significant after adjusting for APOE E4 in addition to the above covariates in a subset with genotyping data. Furthermore, participants with higher PiL had a later onset age for cognitive impairment compared to participants with lower PiL after accounting for these covariates.

Higher PiL was associated with approximately 28% lower risk for developing cognitive impairment and a later onset of cognitive impairment across the studied ethnic/racial groups, even among those with genetic risk for dementia. These findings indicate that fostering a sense of life purpose has the potential to reduce cognitive impairment and dementia risk.