TABLE 1.
Selected participant characteristics of American Indians, 64 to 95 years of age, stratified by apolipoprotein E (APOE) ε4 carrier status
| APOE ε4 status Non-carriers* | Carriers* | |||
|---|---|---|---|---|
| n = 630 (77.7%) | n = 181 (22.3%) | P | ||
| Age (years), mean (SD) | 73.1 (6.0) | 72.7 (5.5) | .34 | |
| Male, n(%) | 204 (32.4%) | 59 (32.6%) | .96 | |
| Field center, n(%) | Northern Plains | 294 (46.7%) | 78 (43.1%) | .52 |
| Southern Plains | 259 (41.1%) | 83 (45.9%) | ||
| Southwest | 77 (12.2%) | 20 (11.0%) | ||
| BMI (kg/m2), mean (SD) | 31.3 (6.4) | 31.8 (7.1) | .39 | |
| Education categories | Up to high school | 126 (20.0%) | 36 (19.9%) | .11 |
| Grad. high school | 170 (27.0%) | 38 (21.0%) | ||
| Any college | 250 (39.7%) | 71 (39.2%) | ||
| College graduate | 84 (13.3%) | 36 (19.9%) | ||
| Hypertension | 510 (81.0%) | 145 (80.1%) | .80 | |
| Diabetes mellitus | 312 (49.5%) | 87 (48.1%) | .73 | |
| High LDL | 245 (38.9%) | 80 (44.2%) | .20 | |
| CKD | 300 (47.6%) | 79 (43.6%) | .35 | |
| Volume: brain (% IC), mean (SD) | 77.4 (4.6) | 77.6 (4.8) | .56 | |
| Volume: hippocampus (% IC), mean (SD) | 0.5 (0.1) | 0.5 (0.1) | .62 | |
| Volume: left hippocampus (% IC), mean (SD) | 0.3 (0.0) | 0.3 (0.0) | .95 | |
| Volume: right hippocampus (% IC), mean (SD) | 0.3 (0.0) | 0.3 (0.0) | .42 | |
| Learning: CVLT best of trials 3 and 4 | 6.9 (1.5) | 6.9 (1.5) | .62 | |
| Learning: CVLT across-trial consistency score | 82.3 (14.3) | 82.7 (14.1) | .74 | |
| Learning & memory: CVLT % retained | −22.7 (27.1) | −21.8 (27.1) | .68 | |
| Memory: CVLT short delay free recall | 5.9 (2.0) | 6.0 (2.1) | .36 | |
| Memory: CVLT long delay free recall | 5.4 (2.3) | 5.5 (2.2) | .63 | |
| Memory: CVLT long delay cued recall | 5.9 (2.0) | 6.1 (2.1) | .26 | |
| Memory: CVLT recognition / discrimination | 2.6 (0.8) | 2.6 (0.8) | .95 | |
| Processing speed: WAIS coding | 44.4 (16.1) | 42.4 (15.0) | .14 | |
| Phonemic fluency, executive function: COWA | 24.1 (11.3) | 25.3 (11.9) | .21 | |
| General cognition: 3MSE | 88.5 (8.8) | 87.9 (11.0) | .48 | |
*
APOE ε4 non-carriers include haplotypes 3/2 (n = 42, 5.1%) and 3/3 (n = 588, 72.5%) but no 2/2. APOE ε4 carriers include haplotypes 4/2 (n = 5, 0.6%), 4/3 (n = 170, 21.0%), and 4/4 (n = 6, 0.7%).
Number and percent, n(%). BMI, body mass index;, kg/m2, kilograms per meter squared; LDL, low-density lipoprotein; CKD, chronic kidney disease; % IC, volumetric measures presented as % intracranial volume; CVLT, California Verbal Learning Test; WAIS, Weschler Adult Intelligence Scale; COWA, Controlled Oral Word Association; 3MSE, Modified Mini Mental Status Examination.