Abstract
We investigated associations between apolipoprotein E (APOE) alleles and motor manifestations in Alzheimer's dementia (AD) capitalizing on National Alzheimer's Coordinating Center data: the baseline evaluations of older adults (≥60 years) with a diagnosis of AD were analyzed. Those with a concomitant diagnosis Parkinson's disease or other parkinsonian syndrome, and those treated with anti-parkinsonian agents were excluded. Three APOE groups were formed: APOE2 (APOE2 carriers), APOE3 (APOE3/APOE3) and APOE4 (APOE4/APOE4, APOE4/APOE3). UPDRS-III was used to assess the presence or absence of motor signs in 9 domains. Adjusted binary logistic models featuring the three APOE groups as exposures and motor domains as outcomes were estimated. There were 389 individuals in the APOE2, 1799 in the APOE3 and 2791 in the APOE4 groups. Compared to the APOE2 group, individuals in the APOE4 group had lower odds of having at least one motor sign [0.64 (0.50-0.82)]. Among motor signs, rigidity [0.53 (0.34-0.81)], bradykinesia [0.56 (0.40-0.77)], impaired chair rise [0.54 (0.37-0.78)] and impaired posture-gait [0.54 (0.36, 0.81)] exhibited significant associations. Exploratory analyses featuring APOE genotypes suggested dose-response relationships for both APOE2 and APOE4. In conclusion, APOE2 confers a risk towards motor (mainly parkinsonian) signs in AD. APOE4 may have a protective effect.