Table 1.

Baseline Characteristics of AIBL and ADNI Cohorts^a

Characteristic	No. (%)
	AIBL		ADNI		P Valuesb
	HC (n = 754)	AD (n = 207)	HC (n = 57)	AD (n = 108)	HC	AD	Overall
Age, y
<70	261 (35)	22(11)	2 (4)		<.0001	.02	<.0001
70–79	333 (45)	41 (21)	32 (56)
≥80	149 (20)	132 (68)	23 (40)
Sex
Male	319 (42)	80 (39)	28 (49)		.32	.40	.24
Female	435 (48)	127 (61)	29 (51)
Educational level, y
0–6	5 (1)	12 (6)	0		<.0001c	<.0001c	<.0001c
7–8	56 (7)	34 (17)	19 (33)
9–12	284 (38)	73 (36)	32 (56)
13–15	149 (20)	36 (18)	1 (2)
>15	257 (34)	46 (23)	5 (9)
BMI
<25	294 (41)	77 (54)	18 (32)		.43	.44	.68
25–29.9	298 (41)	53 (37)	26 (46)
>30	128 (18)	12 (8)	12 (21)
MMSE score, mean (SD)	28.9 (1.2)	18.9 (5.3)	28.9 (1.2)	23.6(1.9)	.81	<.0001	<.0001c
CDR score
0	714 (95)	0	46 (82)		.0004c	.19c	<.0001c
0.5	38 (5)	65 (31)	10 (18)
1	1 (0.1)	113 (55)	0
>1	0	29 (14)	0
APOE ε4
Negative	572 (76)	79 (38)	53 (93)		.003	.31	.0003
Positive	182 (24)	128 (62)	4 (7)

Abbreviations: AD, Alzheimer disease; ADNI, Alzheimer Disease Neuroimaging Initiative; AIBL, Australian Imaging Biomarker and Lifestyle study; APOE, apolipoprotein E; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CDR, Clinical Dementia Rating; HC, healthy controls; MMSE, Mini-Mental State Examination.

^aCross-tabulation frequencies are shown for demographic and clinical characteristics of the AIBL and ADNI cohorts between the HC and AD groups.

^bP values were calculated from the comparison of the 2 cohorts with and without stratification for clinical classification. Educational level shown as per ADNI classifications (ADNI Enrol: Demographics). Missing data were observed within AIBL for educational level (HC, 3; AD, 6), BMI (HC, 34), MMSE (HC, 4), and CDR (HC, 1).

^cRepresents the P value used from the Fisher exact test.