Sixty-five percent of NACC participants were women, 83% were white, and 51% were born before 1920. Seventy-three percent of participants had 12 or more years of education, 19% had 8 to 11 years, and 8% had less than 8 years. Reported age at onset was younger with increasing amount of education (log-rank test, P < .001) (Figure). This finding was confirmed in the Cox proportional hazards analysis when differences between the individual survival curves were tested controlling for sex, race, birth stratum, and ADC (Table). The moderate and normative education groups showed a slightly faster rate of reported age of AD onset over time compared with the low education group, and the normative group had a slightly faster rate than the moderate group (Table). Male sex and white race were associated with earlier age at onset, and birth before 1920 was associated with later age at reported onset. The mean (SD) number of years from age at onset to age at first assessment at the ADC was similar for the normative (4.25 [3.3] years), moderate (4.29 [3.2] years), and low (4.28 [3.5] years) education groups (P = .71), though mean (SD) MMSE scores at first assessment differed (P < .001) across the groups (normative, 18.0 [7.2]; moderate, 15.3 [6.7]; low, 12.9 [6.3]).