Table 3.
Threshold effects of Alzheimer’s disease pathology on the odds of dementia in the most elderly
| Age under 90 (n = 113) | Age 90 and over (n = 96) | |
|---|---|---|
| CERAD score and odds of dementia (reference CERAD 0) | ||
| CERAD 1 | 0.9 (0.2–4.8) | 0.8 (0.2–3.6) |
| CERAD 2 | 3.6 (1.3–11.9) | 3.4 (1.2–12.4) |
| CERAD 3 | 15.2 (4.3–50) | 29.1 (4.2–163) |
| Mean CERAD score | 1.6 ± 1.1 | 1.7 ± 1.0 |
| Attributable risk of dementia for CERAD score >1 | 55% | 53% |
| Braak score and odds of dementia (reference Braak 1 and 2) | ||
| Braak 3 | 3.8 (1.3–11.9) | 1.5 (0.4–5.5) |
| Braak 4 | 5.3 (1.9–14.7) | 2.7 (1.1–12.2) |
| Braak 5 or 6 | 65 (7.4–569) | 41 (5.2–373) |
| Mean Braak score | 3.1 ± 1.3 | 3.9 ± 1.2* |
| Attributable risk of dementia for Braak score >2 | 59% | 42% |
| Composite Alzheimer’s disease pathology score and odds of dementia (reference score of 2) | ||
| Score 3 | 0.5 (0.1–2.4) | 0.7 (0.2–1.7) |
| Score 4 | 5.0 (1.6–15) | 2.8 (1.1–8.3) |
| Scores 5 or 6 | 21.6 (5.8–73) | 26.8 (5.5–148) |
| Mean composite score | 3.5 ± 1.3 | 4.0 ± 1.2* |
| Attributable risk of dementia for Alzheimer’s disease pathology score >3 | 63% | 54% |
Subjects were divided into two age groups. Individual Alzheimer’s disease pathology scores were transformed into categorical variables and were run simultaneously against the indicated reference with dementia as the outcome. Sex was included as a covariate. Braak and composite Alzheimer’s disease pathology scores of five and six were combined for the analysis to avoid an infinite odds ratio seen in subjects with scores of six.
*P < 0.01 (ANOVA) compared with subjects <90 years.