Abstract
Background
The older Hispanic/Latino population in the U.S. is projected to grow faster than any racial/ethnic group in the country. Little is known about brain aging in this population, and we remain poorly equipped to detect and track brain changes in this population. We characterized brain aging in a sample of Hispanics/Latinos from diverse backgrounds and investigated differences by sex.
Method
Nunweighted=1,389 Hispanics/Latinos (ages 39‐85 years; 66% female) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) underwent brain magnetic resonance imaging (MRI) as part of the Study of Latinos ‐ Investigation of Neurocognitive Aging MRI (SOL‐INCA MRI) ancillary study. MRI outcomes of interest included global (gray matter, total brain) and regional (lobar cortices, hippocampus) brain volumes, lateral ventricle volume, and total white matter hyperintensity (WMH) volume. All MRI measures were residualized for total cranial volume prior to calculating brain aging trajectories using linear regressions that included sex, height, and Hispanic/Latino background as terms in the model. We also tested for effect modification by sex.
Result
Mean age was 60.8± 10.3 years. Age was associated with decrements in total (β
total
=‐0.66; p<0.001) and hippocampal volumes (β
hippocampus
=‐0.20; p<0.001) as well as incremental enlargements in lateral ventricle and WMH volumes (β
log_lateralvent
=0.48; p<0.001; β
log_WMH
=0.54; p<0.001). Age was also inversely linked to total brain gray matter as well as all lobar cortical gray matter volumes. Age‐related decrements in total and regional brain volumes, but not lateral ventricle or WMH, were exacerbated in men relative to women (all p<0.05). Adjusting for height and background, women had larger total brain (standardized beta β
total
=0.27; p<0.001), frontal (β
frontal
=0.27; p<0.001), and parietal (β
parietal
=0.17; p=0.025) volumes, smaller hippocampal and lateral ventricle volumes, and larger gray matter volumes, but did not differ in WMH as compared to men.
Conclusion
These findings suggest that increasing age is associated with smaller regional MRI brain measures in Hispanic/Latino individuals. Aging patterns in gray matter volumes appeared to be exacerbated among men compared to women whereas age‐related differences in lateral ventricular volume and white matter hyperintensities were consistent between sexes. Our findings help establish the trajectories of brain aging among middle‐aged and older Hispanics/Latinos.