Table 3. Aβ42 in the prediction of X-tau by age quartiles.
| Quartile | N | age range | Aβ42 variance a | Dependent variable | linear fit Aβ42 | quadratic fit Aβ42 | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| β b | 95% CI c | p value | β b | 95% CI c | p value | |||||
| Q1 | 162 | 45.1–62.9 | 0.80 | P-tau181 | 0.42 | 0.25, 0.59 | < .01 | 0.18 | 0.06, 0.30 | < .01 |
| Q2 | 162 | 63.0–70.31 | 0.96 | 0.20 | 0.01, 0.39 | < .05 | 0.28 | 0.17, 0.39 | < .01 | |
| Q3 | 164 | 70.33–75.9 | 1.03 | -0.23 | -0.41, -0.04 | < .05 | 0.19 | 0.01, 0.36 | < .05 | |
| Q4 | 163 | 76.0–89.7 | 1.18 | -0.18 | -0.32, -0.03 | < .05 | 0.14 | 0.03, 0.25 | < .05 | |
| Q1 | same as above | T-tau | 0.44 | 0.27, 0.60 | < .01 | 0.14 | 0.02, 0.25 | < .05 | ||
| Q2 | 0.30 | 0.11, 0.49 | < .01 | 0.25 | 0.15,0.35 | < .01 | ||||
| Q3 | -0.11 | -0.29, 0.07 | 0.22 | 0.17 | 0.01, 0.33 | < .05 | ||||
| Q4 | -0.07 | -0.22, 0.08 | 0.34 | 0.18 | 0.07, 0.29 | < .01 | ||||
a. Significant increase in variance across quartiles.
b. β coefficients are unstandardized values from the GEE with CSF z scores.
c. The 95% CI of the β coefficients are calulated using robust (Huber-White) sandwich estimators of the standard error.