APOE and Alzheimer disease: Honea et al. [82] did consider APOE genotype in their follow-up study of correlations between VO2peak and volume of specific brain regions using voxel-based morphometry in 71 patients diagnosed with early-stage AD (CDR 0.5 to 1.0; mean age 74.3 years; APOE-ε4 allele status: n = 7 homozygotes, n = 36 heterozygotes, n = 18 non-carriers) and 67 healthy older adults without dementia (CDR = 0; mean age 73.3 years; APOE-ε4 allele status: n = 3 homozygotes, n = 15 heterozygotes, n = 29 non-carriers), most of whom also participated in the Burns et al. [81] study.