In an epidemiological sample the apolipoprotein E4 allele is associated to dementia and loss of memory function only in the very old.

The apolipoprotein E4 allele has been reported to be associated with late onset Alzheimer's disease. Here we report the relation of several neuropsychological test parameters and the diagnosis of dementia to the apolipoprotein E polymorphism in an epidemiological sample of 477 subjects aged 70-103 years. The apolipoprotein E4 allele was found to be associated with reduced performance in several sensitive neuropsychological memory tests and with diagnosis of dementia only in the oldest subjects (> 84 years). The association with dementia in this population based sample was much weaker than previously described and became only significant in a logistic regression analysis when age was included in the model.