Apolipoprotein E polymorphism and dementia: a hospital-based study from southern India.

BACKGROUND/AIMS To evaluate the ApoE gene polymorphism among patients with dementia from southern India. METHODS Persons with dementia attending a geriatric clinic in a hospital setting located in southern India and matched controls were recruited. All subjects were evaluated on standard assessments and were diagnosed according to the ICD-10; genotyping was done at the apolipoprotein E (ApoE) locus. RESULTS The study comprised 212 cases and 195 controls. The ApoE4 allele was significantly more prevalent in dementia (λ = 0.18 vs. λ = 0.07; p = 0.0018), especially in the Alzheimer's disease subgroup (n = 137; λ = 0.21 vs. λ = 0.07; p < 0.001), with a trend in vascular dementia subtype (n = 31; λ = 0.17 vs. λ = 0.07) in comparison with the control group. ApoE4 carrier status did not differ between the other dementia group (n = 44) and controls (p > 0.20), or between the Alzheimer's group and vascular dementia groups. Cognitive and functional deficits were not correlated to the presence ApoE4 polymorphism in the dementia group. CONCLUSION The study confirmed the positive association of the ApoE4 polymorphism in dementia, both in the Alzheimer's and vascular etiology subgroups. Influence of this polymorphism on various clinical phenotypes, including extent of cognitive and functional deficits, needs further evaluation.