Apolipoprotein E Alleles and Motor Signs in Older Adults with Alzheimer's Dementia

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.

Keywords: Alzheimer’s dementia; apolipoprotein E; bradykinesia; gait; motor signs; posture; rigidity; tremor.

Figure 1

Participant flowchart. APOE: apolipoprotein E; UPDRS-III: Unified Parkinson’s disease rating scale part III.

Figure 2

Prevalence [(those with the respective motor sign per genotype/those with the genotype) *100] of motor manifestations per apolipoprotein E (APOE) genotype in older adults with Alzheimer’s dementia. Different APOE genotypes are represented by different colors (see annotation). The prevalence (%) of each motor sign by APOE genotype is also noted in the table of contents below the bar chart.