Table 4.
Examination of lung volume as an explanatory factor for associations between subclinical interstitial lung disease and obstructive sleep apnea metrics among those with body mass index less than 25 kg/m2*
| Total Effect Coefficient | Direct Effect Coefficient | Indirect Effect Coefficient | Percentage of Total Effect Explained by Lung Volumes | Interpretation | |
|---|---|---|---|---|---|
| HAA | |||||
| oAHI | 0.75 | 0.67 | 0.08 | 11% | Partial (weak) mediation |
| Nadir saturation | 0.03 | 0.02 | 0.01 | 25% | Partial (weak) mediation |
| ILA | |||||
| oAHI | 0.25 | 0.23 | 0.03 | 10% | Partial (weak) mediation |
| Nadir saturation | −0.0028 | −0.0043 | 0.0015 | N/A | Suppression |
Definition of abbreviations: CT = computed tomography; HAA = high-attenuation area; ILA = interstitial lung abnormality; N/A = not applicable; oAHI = obstructive apnea–hypopnea index.
*
Lung volumes were measured on full lung CT scans performed at full inspiration. HAA models are adjusted for age, sex, smoking, site, radiation dose, and percent emphysema. ILA models are adjusted for age, sex, and smoking.