Annualized Decline in Instrumental Activities of Daily Living Is Slower in Hispanics Compared to Non-Hispanics in an Alzheimer’s Disease Sample

Abstract

Abstract Objective Research examining the course of Alzheimer’s disease (AD) in Hispanics is lacking. This study examined demographic, psychiatric, cognitive, and genetic predictors of longitudinal functional change in Hispanics and non-Hispanics with AD. Method Longitudinal change in instrumental activities of daily living (IADL) was examined over 10 years (M = 4.15 years) in 292 subjects (Hispanic = 67, non-Hispanic = 225). All were part of the Texas Alzheimer’s Research & Care Consortium and included those with AD (n = 217) and those with mild cognitive impairment at baseline who progressed to AD at follow-up (n = 75). Baseline comparisons were conducted between ethnic groups for demographics, Geriatric Depression Scale (GDS-30) score, Mini Mental State Examination (MMSE) score, presence of apolipoprotein ɛ4 alleles (APOE4), and annualized IADL change scores and then entered into a multiple linear regression model as predictors of annualized IADL change. Results The Hispanic group had significantly more females (χ2 = 5.71, p = .017), lower education [MH = 9.96(4.39), MNH = 15.26(2.70)], higher depression scores [GDS-30; MH = 9.45(5.89), MNH = 5.51(4.29)], lower MMSE scores [MH = 23.31(4.33), MNH = 24.65(3.21)], and slower annualized IADL change [MH = 1.19(1.42), MNH = 2.02(1.60)]. Regression results were significant (F = 3.66, p = .001, R2 = .08 ), with higher baseline MMSE (p = .007) and Hispanic origin (p = .010) predicting slower annualized IADL change. Demographics, APOE4 status, and depression did not significantly predict IADL change. Conclusions Higher cognitive functioning at baseline and Hispanic origin was associated with slower functional decline over an average 4-year period of time. Despite having lower MMSE scores at baseline, greater depression, and less education, the Hispanic group had a slower decline in IADLs compared to non-Hispanics. Further research is needed to better understand how/why Hispanic origin is associated with slower functional decline.