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. Author manuscript; available in PMC: 2025 Jul 11.
Published in final edited form as: Chest. 2025 Jan 18;168(1):43–55. doi: 10.1016/j.chest.2024.12.037

Table 2.

Unadjusted correlations between quantitative small airways measures, spirometry and 8-hour TWA endotoxin

2011, N = 404
8-hour TWA Endotoxin		 p-Value 2016, N = 404
8-hour TWA Endotoxin		 p-Value
Small airway measures
   Exp−856 0.053 0.288 0.113 0.023
   E/I MLA 0.060 0.229 0.117 0.019
   RVC−856 to −950 0.065 0.191 0.127 0.011
   Residual−856 0.066 0.187 0.135 0.007
Spirometry
   FEV1 0.044 0.380 0.027 0.583
   pp FEV1 −0.187 <0.001 −0.184 <0.001
   FEV1/FVC −0.145 0.004 −0.118 0.017

Note: Pearson correlation coefficients were reported. p < 0.05 was considered significantly different from zero. Abbreviations: TWA, Time-weighted Average; FEV1, Forced Expiratory Volume in the first 1 second; pp FEV1, percent predicted FEV1; FVC, Forced Vital Capacity; Exp−856, percent gas trapping; E/I MLA, expiratory to inspiratory ratio of mean lung attenuation; RVC−856 to −950, relative volume change of voxels with attenuation between −856 HU and −950 HU; Residual−856, residuals from the linear regression of Exp−856 on the percent of voxels with attenuation less than −950 HU.