Childhood Community Disadvantage and MRI-Derived Structural Brain Integrity After Age 65 Years.

Importance: Prior studies associate late-life community disadvantage with worse brain health. It is relatively unknown if childhood community disadvantage associates with late-life brain health.

Objective: To test associations between childhood residence in an economically disadvantaged community, individual income and education, and late-life cortical brain volumes and white matter integrity.

Design, setting, and participants: This cohort study was conducted in the ongoing harmonized cohorts KHANDLE (Kaiser Healthy Aging and Diverse Life Experiences Study; initiated 2017) and STAR (Study of Healthy Aging in African Americans; initiated 2018) using all available data collected out of a regional integrated health care delivery network in California between cohort initiation and analysis initiation in June 2023. Eligible participants were Kaiser Permanente Northern California member ages 65 years or older. Data were analyzed between June and November 2023.

Exposure: Residence at birth was geocoded and linked to historical Area Deprivation Indices (ADI). ADI is a nationally ranked percentile; community disadvantage was defined as ADI of 80 or higher.

Main outcomes and measures: Regional brain volumes and white matter integrity measures were derived from a random subset of participants who underwent 3T magnetic resonance imaging. Models adjusted for race and ethnicity, sex, and parental education.

Results: Of a total 2161 individuals in the combined cohort, 443 individuals were eligible for imaging (mean [SD] age, 76.3 [6.5] years; 253 female [57.1%]; 56 Asian [12.6%], 212 Black [47.9%], 67 Latino [15.1%], 109 White [24.6%]). Imaging participants had a mean (SD) 15.0 (2.5) years of education, and 183 (41.3%) earned $55 000 to $99 999 annually. Fifty-four participants (12.2%) resided in a disadvantaged childhood community. Childhood community disadvantage was associated with smaller gray matter volumes overall (-0.39 cm3; 95% CI, -0.65 to -0.10 cm3) and in the cerebellum (-0.39 cm3; 95% CI, -0.66 to -0.09 cm3), hippocampus (-0.37 cm3; 95% CI, -0.68 to -0.04 cm3), and parietal cortex (-0.25 cm3; 95% CI, -0.46 to -0.04 cm3) and larger mean lateral ventricle (0.44 cm3; 95% CI, 0.12 to 0.74 cm3), third ventricle (0.28 cm3; 95% CI, 0.03 to 0.55 cm3), and white matter hyperintensity volume (0.31 cm3; 95% CI, 0.06 to 0.56 cm3). Educational attainment and late-life income did not mediate these associations.

Conclusions and relevance: In this cohort study of racially and ethnically diverse health plan members, childhood community disadvantage was associated with worse late-life brain health independent of individual socioeconomic status. Future work should explore alternative pathways (eg, cardiovascular health) that may explain observed associations.