Table 3.

Multinomial logistic regression

	Resolved Chronic Bronchitis*		New Chronic Bronchitis*		Persistent Chronic Bronchitis+*
	OR	95% CI	OR	95% CI	OR	95% CI
Univariable
Quitting smoking†	3.436	2.211–5.339	1.120	0.588–2.133	1.362	0.708–2.620
Resuming smoking†	1.190	0.364–3.999	3.369	1.679–8.087	0.996	0.232–4.277
Persistent smoking†	1.806	1.239–2.634	1.734	1.178–2.551	2.784	1.902–4.074
Smoking, pack-years	1.008	1.001–1.015	1.013	1.007–1.020	1.020	1.014–1.026
GERD	1.429	1.016–2.010	1.361	0.939–1.972	1.563	1.064–2.255
Male sex	1.547	1.110–2.155	1.394	0.976–1.990	1.462	1.021–2.093
White race	1.154	0.799–1.688	1.116	0.751–1.657	1.524	0.994–2.336
FEV1% pred	0.983	0.977–0.989	0.981	0.975–0.988	0.977	0.971–0.984
Multivariable
Quitting smoking†	4.289	2.689–6.842	1.328	0.682–2.585	1.859	0.936–3.691
Resuming smoking†	1.449	0.421–4.984	4.585	2.008–10.471	1.350	0.301–6.041
Persistent smoking†	2.867	1.872–4.392	2.621	1.677–4.096	5.767	3.702–8.983
Smoking, pack-years	1.001	0.993–1.008	1.007	1.000–1.015	1.013	1.006–1.020
GERD	1.572	1.099–2.249	1.430	0.970–2.109	1.697	1.145–2.515
Male sex	1.493	1.056–2.111	1.227	0.847–1.778	1.242	0.846–1.823
White race	1.651	1.089–2.503	1.327	0.843–2.090	2.287	1.415–3.697
FEV1% pred	0.982	0.975–0.998	0.979	0.972–0.986	0.973	0.966–0.980

Definition of abbreviations: CI = confidence interval; FEV₁% pred = FEV₁ expressed as a percentage of the predicted value; GERD = gastroesophageal reflux disease; OR = odds ratio; persistent chronic bronchitis+ = subjects positive at phase 1/positive at phase 2 for chronic bronchitis.

^*Versus persistent chronic bronchitis–.

^†Versus persistent ex-smokers.