Table 1.

Demographic characteristics

Demographic characteristic	No dementia	Incident AD
No.	1021	104
Age at baseline, years (mean ± SD)***	76.3 ± 6.1	80.7 ± 7.0
Sex, n (% women)	693 (67.9)	75 (72.1%)
Education, years (mean ± SD)***	10.4 ± 4.7	6.7 ± 4.8
Ethnicity, n (%)***	319 (97)	10 (3)
White	338 (91.6)	31 (8.4)
African American	364 (85.2)	63 (14.8)
Hispanic
APOE ε4 allele, n (%)	265 (26.3%)	28 (27.2%)
AB40, baseline (mean ± SE)	79.6 ± 1.9	87.2 ± 5.4
AB40, follow up (mean ± SE)	120.3 ± 1.6	128.8 ± 4.5
AB42, baseline (mean ± SE)*	37.3 ± 0.77	42.2 ± 2.9
AB42 follow up (mean ± SE)	48.2 ± 0.7	47.9 ± 2.0
AB42/AB40 baseline (mean ± SE)	0.60 ± 0.01	0.64 ± 0.06
AB42/AB40 follow up (mean ± SE)	0.46 ± 0.01	0.46 ± 0.01

*, P < 0.05; **, P < 0.01;

***, P < 0.001.