APOE and Alzheimer disease: Other limitations are that diet and covariate data were only assessed at baseline and we could not evaluate potential exposure and lifestyle changes during follow-up, and that we had no data available on genetic traits such as apolipoprotein E (APOE) genotype (presence of ε4 alleles), although previous evidence suggest that APOE is not associated with MD and has no influence on the association between MD and AD [17].