Factors associated with morphometric brain changes in cognitively normal aging

Objective Cognitive impairment is associated with reductions in brain weight and volume. The factors related to morphometric brain changes in cognitively normal aging remain unknown. We aimed to identify which clinical factors are associated with morphometric brain changes in cognitively normal aging. Methods A cross-sectional study of 414 subjects, ≥50 years old submitted to clinical assessment and brain autopsy, after informed consent, was carried out at the São Paulo Autopsy Service, Brazil. Data on cognitive and functional evaluations were collected through structured interview applied to the next-of-kin. Brain weight (g) and volume (mL) measurements were obtained and adjusted for head circumference (cm). Associations between brain weight/volume and related factors were obtained through univariate and multivariate analysis. Results Participants were predominantly male (60.4%), Caucasian (69%), with mean age of 67.1 ± 10.9 years. Mean brain weight was 1219.2 ± 140.9 g, and mean brain volume was 1217.1 ± 152.3 mL. Head circumference was independently associated with low brain weight (p<0.001) and volume (p<0.001). Total and adjusted brain weight and volume decreased in some conditions. Female gender (p<0.001), hypertension (p<0.009), coronary artery disease (p<0.013) and walking assistance (p<0.011) were associated with lower adjusted brain weight while schooling was associated with higher adjusted brain weight (p<0.003). Female gender (p<0.001), age (p<0.001) and hypertension (p<0.011) were associated with low adjusted brain volume. Conclusion Morphometric brain changes occur despite the absence of cognitive impairment and were predominantly associated with age, female gender, mobility impairment and cardiovascular conditions. Schooling may be a protective factor.