Effects of apolipoprotein E-epsilon4 and -epsilon2 in amnestic mild cognitive impairment and dementia in Shanghai: SCOBHI-P.

OBJECTIVE: To determine apolipoprotein E (APOE)-epsilon4 and -epsilon2 frequencies and risk of mild cognitive impairment (MCI) and dementia in Shanghai, China.

METHODS: A total of 34 MCI and 34 dementia cases were recruited from an urban Memory Disorders Clinic and 32 controls were recruited from a residential community served by the clinic. Apolipoprotein E was genotyped using standard methods.

RESULTS: Among controls, frequencies were epsilon2, 0.11; epsilon3, 0.84; and epsilon4, 0.05; among MCI, 0.05, 0.77, and 0.18; and for dementia, 0.02, 0.84, and 0.15, respectively. In education-adjusted models, the odds ratio (OR) = 5.6 for dementia (95% CI = 1.09-29.3) and 4.7 for MCI (95% CI = 0.90-25.2) associated with any epsilon4 allele. The epsilon2 allele was inversely associated with dementia (OR = 0.12, 95% CI = 0.013-0.997) and MCI (OR = 0.38, 95% CI = 0.08-1.61).

CONCLUSIONS: APOE-epsilon4 increases and -epsilon2 decreases the risk of dementia vs normal cognition. Similar trends were observed for amnestic mild cognitive impairment (aMCI).