Table 3. Odds ratios (ORs) and 95% confidence intervals (CIs) for obstructive lung pattern based on free thyroxine quartiles.

	fT4 quartile
	Q1 (0.89–1.09 ng/dL) (n = 294, 23.4%)	Q2 (1.10–1.19 ng/dL) (n = 321, 25.5%)	Q3 (1.20–1.30 ng/dL) (n = 317, 25.2%)	Q4 (1.31–1.76 ng/dL) (n = 329, 25.9%)
Obstructive pattern
Model 1  Model 2  Model 3  Model 4	1.000 1.000 1.000 1.000	1.984 (0.864, 4.556) 1.944 (0.819, 4.614) 2.041 (0.817, 5.095) 1.998 (0.797, 5.011)	2.898 (1.326, 6.334) † 2.777 (1.246, 6.189) † 2.818 (1.243, 6.389) † 2.875 (1.265, 6.535) †	3.664 (1.731, 7.754) * 2.878 (1.322, 6.268) † 3.000 (1.340, 6.716) † 2.970 (1.287, 6.854) †

fT4, free thyroxine.

Model 1, unadjusted; Model 2, with adjustment for age and sex; Model 3 as model 2, with additional adjustment for occupation, smoking, alcohol consumption, walking activity, and body mass index; Model 4 as model 3, with additional adjustment for glycated hemoglobin, and thyroid-stimulating hormone.

OR and 95% CI for risk of obstructive lung pattern were estimated using logistic regression models. All p values and 95% CI for OR were corrected by Bonferroni’s method due to multiple testing.

*p<0.001,

†0.001≤p<0.01.