TABLE 2.
Changes in cognitive scores and their rates of changes per standard deviation increase in Alzheimer's disease biomarker concentrations from linear mixed effects models.
| AD biomarkers | SD | Time effect (95% CI) | Main effect (95% CI) | Interaction with time (95% CI) | p for interaction |
|---|---|---|---|---|---|
| Symbol Digit Modalities Test | |||||
| Aβ42, pg/mL | 4.4 | −0.38 (−0.58, −0.18) | −1.19 (−2.66, 0.28) | 0.03 (−0.06, 0.12) | 0.57 |
| Aβ42/40 ratio | 0.04 | −0.31 (−0.51, −0.12) | −0.14 (−1.59, 1.31) | −0.01 (−0.12, 0.09) | 0.82 |
| Total tau, pg/mL | 2.8 | −0.33 (−0.49, −0.18) | 1.06 (−0.41, 2.53) | 0.01 (−0.09, 0.10) | 0.92 |
| P‐tau181, pg/mL | 10.9 | −0.26 (−0.44, −0.07) | 0.57 (−1.00, 2.15) | −0.08 (−0.18, 0.01) | 0.08 |
| Digit Span Backwards Test | |||||
| Aβ42, pg/mL | 4.4 | 0.01 (−0.05, 0.06) | 0.03 (−0.26, 0.31) | −0.01 (−0.03, 0.02) | 0.64 |
| Aβ42/40 ratio | 0.04 | −0.06 (−0.11, 0) | −0.04 (−0.32, 0.23) | 0.03 (0.01, 0.06) | 0.03 |
| Total tau, pg/mL | 2.8 | 0.01 (−0.04, 0.05) | 0.07 (−0.22, 0.35) | −0.01 (−0.03, 0.02) | 0.54 |
| P‐tau181, pg/mL | 10.9 | −0.02 (−0.07, 0.03) | −0.09 (−0.42, 0.24) | 0.02 (−0.01, 0.05) | 0.17 |
| East Boston Memory Test immediate recall | |||||
| Aβ42, pg/mL | 4.4 | −0.03 (−0.08, 0.02) | −0.04 (−0.25, 0.17) | 0.01 (−0.01, 0.04) | 0.31 |
| Aβ42/40 ratio | 0.04 | −0.03 (−0.08, 0.02) | −0.15 (−0.36, 0.05) | 0.02 (−0.01, 0.05) | 0.22 |
| Total tau, pg/mL | 2.8 | −0.02 (−0.07, 0.01) | 0.03 (−0.18, 0.23) | 0.02 (−0.01, 0.04) | 0.11 |
| P‐tau181, pg/mL | 10.9 | −0.03 (−0.08, 0.02) | 0.03 (−0.20, 0.26) | 0.02 (−0.01, 0.05) | 0.11 |
| East Boston Memory Test–Delayed recall | |||||
| Aβ42, pg/mL | 4.4 | −0.03 (−0.08, 0.03) | −0.06 (−0.28, 0.16) | 0.01 (−0.01, 0.03) | 0.42 |
| Aβ42/40 ratio | 0.04 | −0.02 (−0.07, 0.03) | −0.13 (−0.35, 0.08) | 0.01 (−0.02, 0.03) | 0.73 |
| Total tau, pg/mL | 2.8 | −0.02 (−0.06, 0.02) | 0.11 (−0.11, 0.33) | 0.01 (−0.01, 0.04) | 0.28 |
| P‐tau181, pg/mL | 10.9 | −0.04 (−0.09, 0.01) | 0.05 (−0.19, 0.30) | 0.02 (−0.01, 0.05) | 0.12 |
Note: All models were adjusted for age at baseline, race, education, follow‐up time (year), smoking status, alcohol drinking, menopausal status, and Center for Epidemiologic Studies Depression Scale score. Multiplicative interaction terms between AD biomarkers and follow‐up time were also included in the models to estimate the associations between AD biomarkers and rate of changes in cognitive scores.
Abbreviations: Aβ, amyloid β; AD, Alzheimer's disease; CI, confidence interval; p‐tau181: phosphorylated tau181; SD, standard deviation.