Table 3.
Between subject variation in AD biomarkers and covariance parameter estimates
| Parameters | Estimate | 95% CI | P-value |
|---|---|---|---|
| OSA+ vs. OSA− (cognitive normal patients) | |||
| Florbetapir SUVR over time | 0.06 | .02, .11 | <0.0001 |
| Florbetapir SUVR over time (covariance) | −0.06 | −.09, −.04 | <0.0001 |
| CSF Aβ-42 over time | −2.71 | −3.11, −2.35 | <0.0001 |
| CSF Aβ-42 over time (covariance) | 3.93 | 3.56, 4.31 | <0.0001 |
| CSF T-tau over time | 3.68 | 3.31, 4.07 | <0.0001 |
| CSF T-tau over time (covariance) | −2.89 | −3.51, −2.29 | <0.0001 |
| CSF P-tau over time | 1.22 | 1.02, 1.42 | <0.0001 |
| CSF P-tau over time (covariance) | −1.21 | −1.71, −0.74 | <0.0001 |
| OSA+ vs. OSA− (mild cognitive impairment patients) | |||
| Florbetapir SUVR over time | 0.08 | .05, .12 | <0.0001 |
| Florbetapir SUVR over time (covariance) | −0.06 | −0.09, −0.04 | <0.0001 |
| CSF Aβ-42 over time | −2.62 | −3.23, −2.03 | <0.0001 |
| CSF Aβ-42 over time (covariance) | 2.69 | 2.02, 3.36 | <0.0001 |
| CSF tau volume over time | 2.21 | 1.58, 2.86 | <0.0001 |
| CSF tau over time (covariance) | −1.89 | −2.91, −0.87 | <0.0001 |
| CSF P-tau over time | 1.74 | 1.22, 2.27 | <0.0001 |
| CSF P-tau over time (covariance) | −1.48 | −2.05, −0.94 | <0.0001 |
| OSA+ vs. OSA− (Alzheimer’s disease patients) | |||
| Florbetapir SUVR over time | 0.07 | −1.19, 1.33 | 0.33 |
| Florbetapir SUVR over time (covariance) | −0.29 | −2.07, 1.49 | 0.31 |
| CSF Aβ-42 over time | −1.11 | −3.31, 1.09 | 0.53 |
| CSF Aβ-42 over time (covariance) | −1.14 | −3.38, 1.63 | 0.56 |
| CSF T-tau over time | 0.26 | −1.02, 1,28 | 0.47 |
| CSF T-tau over time (covariance) | −0.15 | −1.94, 1.64 | 0.47 |
| CSF P-tau over time | 0.94 | 0.23, 1.65 | 0.11 |
| CSF P-tau over time (covariance) | −0.16 | −1.66, 1.34 | 0.11 |
These analyses allowed us to examine whether there was significant variation between OSA+ and OSA− subjects in mean AD biomarker level at baseline, as well as whether significant variation in the change in AD biomarker level over time occurred. Furthermore, the covariance between the baseline AD biomarker level and AD biomarker change over time indicated whether OSA+ or OSA− subjects had experienced a faster increase or decrease in AD biomarker level over time. It also allowed for assessment of significant differences in the rate-of-change in AD biomarker level between OSA groups over time. Models were adjusted for age, sex, BMI, education, CPAP use, ApoE4 status, alcohol intake, baseline biomarker data, history of respiratory disease, hypertension, diabetes, and history of cardiovascular disease (e.g. including ischemic heart disease, heart failure, and stroke/TIA), and history of traumatic brain injury.
Aβ = amyloid beta; ApoE4 = apolipoprotein epsilon4; BMI = body mass index; CSF = cerebrospinal fluid; tau = tau protein; P-tau = phosphorylated tau.