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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 5.

Multivariate analysis of the association between 8-hour TWA endotoxin and spirometry

8-hour TWA
Endotoxina
EU/m3)		 FEV1 p-Value pp FEV1 p-Value FEV1/FVC p-Value
All, N = 404
 Survey year 2011
  ≤ 50 - - - - - -
  50 - 1,500 17.546 0.759 0.090 0.972 −0.003 0.717
  1,500 - 2,300 −121.286 0.091 −7.022 0.027 0.008 0.484
  2,300 - 3,900 −9.607 0.892 −0.553 0.859 −0.012 0.314
  > 3,900 −135.806 0.071 −6.717 0.043 −0.014 0.274
 Survey year 2016
  ≤ 50 - - - - - -
  50 – 1,500 −54.546 0.341 −2.386 0.345 −0.009 0.364
  1,500 - 2,300 −164.020 0.023 −8.570 0.007 −0.003 0.774
  2,300 - 3,900 −50.986 0.472 −1.253 0.688 −0.008 0.495
  > 3,900 −155.622 0.041 −6.634 0.048 0.003 0.788
 Difference
  ≤ 50 - - - - - -
  50 - 1,500 −72.093 0.013 −2.477 0.065 −0.005 0.455
  1,500 - 2,300 −42.734 0.245 −1.549 0.361 −0.012 0.181
  2,300 – 3,900 −41.379 0.248 −0.700 0.671 0.004 0.656
  > 3,900 −19.816 0.598 0.083 0.962 0.017 0.058
Cotton worker, N = 178
 Survey year 2011
  ≤ 50 - - - - - -
  50 - 1,500 −17.182 0.901 −0.922 0.871 −0.006 0.786
  1,500 - 2,300 −148.325 0.303 −7.517 0.208 0.006 0.778
  2,300 - 3,900 −51.750 0.728 −1.928 0.754 −0.015 0.508
  > 3,900 −161.792 0.290 −7.134 0.260 −0.018 0.429
 Survey year 2016
  ≤ 50 - - - - - -
  50 - 1,500 −71.708 0.603 −3.451 0.546 −0.028 0.185
  1,500 - 2,300 −175.111 0.225 −9.170 0.126 −0.023 0.308
  2,300 - 3,900 −76.496 0.608 −2.747 0.657 −0.028 0.213
  > 3,900 −166.739 0.280 −7.070 0.268 −0.018 0.439
 Difference
  ≤ 50 - - - - - -
  50 - 1,500 −54.526 0.408 −2.529 0.394 −0.022 0.150
  1,500 - 2,300 −26.786 0.701 −1.653 0.598 −0.029 0.070
  2,300 - 3,900 −24.745 0.720 −0.819 0.792 −0.013 0.407
  > 3,900 −4.947 0.944 0.063 0.984 <0.001 0.990

Note: Coefficients and p-Values from the linear mixed model with a random intercept were reported. p < 0.05 was considered significantly different from zero. Spirometry was outcome and 8-hour TWA endotoxin was the exposure variable in the model. The linear mixed models were adjusted for age, gender, height, smoking intensity, survey year, and the interaction between 8-hour TWA endotoxin and survey year (8-hour TWA endotoxin × survey year). 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.

a

50 EU/m3 represents the reference level. 1500 EU/m3 is the 40th percentile, 2300 EU/m3 is the 60th percentile, and 3900 EU/m3 is the 80th percentile. There are 237 textile workers exposed to ≤ 50 EU/m3 endotoxin, 61 workers exposed to 50 - 1,500 EU/m3 endotoxin, 35 workers exposed to 1,500 - 2,300 EU/m3 endotoxin, 37 workers exposed to 2,300 - 3,900 EU/m3 endotoxin, and 34 workers exposed to more than 3,900 EU/m3.