title: Structural MRI Predictors of Late-Life Cognition Differ Across African Americans, Hispanics, and Whites.
abstract: BACKGROUND
  Structural magnetic resonance imaging (MRI) provides key biomarkers to predict onset and track progression of Alzheimer's disease (AD). However, most published reports of relationships between MRI variables and cognition in older adults include racially, ethnically, and socioeconomically homogenous samples. Racial/ethnic differences in MRI variables and cognitive performance, as well as health, socioeconomic status and psychological factors, raise the possibility that brain-behavior relationships may be stronger or weaker in different groups. The current study tested whether MRI predictors of cognition differ in African Americans and Hispanics, compared with non-Hispanic Whites.
  
  
  METHODS
  Participants were 638 non-demented older adults (29% non-Hispanic White, 36% African American, 35% Hispanic) in the Washington Heights-Inwood Columbia Aging Project. Composite scores of memory, language, speed/executive functioning, and visuospatial function were derived from a neuropsychological battery. Hippocampal volume, regional cortical thickness, infarcts, and white matter hyperintensity (WMH) volumes were quantified with FreeSurfer and in-house developed procedures. Multiple-group regression analysis, in which each cognitive composite score was regressed onto MRI variables, demographics, and cardiovascular health, tested which paths differed across groups.
  
  
  RESULTS
  Larger WMH volume was associated with worse language and speed/executive functioning among African Americans, but not among non-Hispanic Whites. Larger hippocampal volume was more strongly associated with better memory among non-Hispanic Whites compared with Hispanics. Cortical thickness and infarcts were similarly associated with cognition across groups.
  
  
  CONCLUSIONS
  The main finding of this study was that certain MRI predictors of cognition differed across racial/ethnic groups. These results highlight the critical need for more diverse samples in the study of cognitive aging, as the type and relation of neurobiological substrates of cognitive functioning may be different for different groups.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Zahodne
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Manly
authors.forename: Atul
authors.initials: A
authors.lastname: Narkhede
authors.forename: Erica Y
authors.initials: EY
authors.lastname: Griffith
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
authors.forename: Nicole S
authors.initials: NS
authors.lastname: Schupf
authors.forename: Richard
authors.initials: R
authors.lastname: Mayeux
authors.affiliation: Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, P & S Box 16, New York 10032, USA. amb2139@columbia.edu.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Brickman
mesh_terms: D001741:Black or African American / Q000523:psychology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000523:psychology*; D001921:Brain / Q000473:pathology*; D003071:Cognition; D005260:Female; D006630:Hispanic or Latino / Q000523:psychology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D009519:New York City / Q000453:epidemiology; D009929:Organ Size; D011446:Prospective Studies; D012044:Regression Analysis; D044465:White People / Q000523:psychology*