APOE and Alzheimer disease: Individuals carrying the APOE ε4 allele (69%) were younger on average (74.4 ± 6.9 vs 76.6 ± 6.5 years; t(716) = 4.09; P <0.001), had an earlier onset of AD (71.4 ± 7.2 vs 73.9 ± 6.7 years; t(713) = 4.50; P <0.001) and had a higher IADL capacity at baseline (14.3 ± 5.1 vs 15.3 ± 4.9 points; t(698) = 2.57; P = 0.010) compared with non-carriers.