A meta-analysis showed that one APOE e4 allele (e4/e2 or e4/e3) was associated with a 2.7-fold (Caucasian) to 5.6-fold (Japanese) increased risk of AD; this risk increased further in people carrying two APOE e4 alleles (11.8-fold for Caucasians, 33.1-fold for the Japanese)7. This evidence concerns the gene APOE and Alzheimer disease.