3 research outputs found
APOE E4 is associated with impaired self-declared cognition but not disease risk or age of onset in Nigerians with Parkinson's disease
The relationship between APOE polymorphisms and Parkinson's disease (PD) in black Africans has not been previously investigated. We evaluated the association between APOE polymorphic variability and self-declared cognition in 1100 Nigerians with PD and 1097 age-matched healthy controls. Cognition in PD was assessed using the single item cognition question (item 1.1) of the MDS-UPDRS. APOE genotype and allele frequencies did not differ between PD and controls (pā>ā0.05). No allelic or genotypic association was observed between APOE and age at onset of PD. In PD, APOE Īµ4/Īµ4 conferred a two-fold risk of cognitive impairment compared to one or no Īµ4 (HR: 2.09 (95% CI: 1.13-3.89; pā=ā0.02)), while APOE Īµ2 was associated with modest protection against cognitive impairment (HR: 0.41 (95% CI 0.19-0.99, pā=ā0.02)). Of 773 PD with motor phenotype and APOE characterized, tremor-dominant (TD) phenotype predominated significantly in Īµ2 carriers (87/135, 64.4%) compared to 22.2% in persons with postural instability/gait difficulty (PIGD) (30/135) and 13.3% in indeterminate (ID) (18/135, 13.3%) (pā=ā0.037). Although the frequency of the TD phenotype was highest in homozygous Īµ2 carriers (85.7%), the distribution of motor phenotypes across the six genotypes did not differ significantly (pā=ā0.18). Altogether, our findings support previous studies in other ethnicities, implying a role for APOE Īµ4 and Īµ2 as risk and protective factors, respectively, for cognitive impairment in PD