Adjusted Odds Ratio for COPD according to Time to First Cigarette (TTFC) among current smokers in PLCO.

COPD cases responded affirmatively to question(s) regarding diagnosis of emphysema (on study baseline questionnaire, follow-up questionnaire in 2006, or both), chronic bronchitis (on study baseline questionnaire), or both. ORs and 95% CIs were determined using logistic regression with adjustments for age, gender (except in gender-stratified analyses), race, education, cigarettes/day, years smoked during lifetime, pack-years, age at smoking initiation, and lung cancer diagnosis prior to follow-up questionnaire. TTFC was categorical (>60 minutes as reference) with the exception of P-trend assessment where TTFC was treated as an ordinal variable.PLCO, Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. P-value for interaction between TTFC*gender interaction term. Significant P-values (Pa N = 6,106; 2 participants were excluded due to missing data on emphysema endpoint.b N = 6,070; 38 participants were excluded due to missing data on bronchitis endpoint.Adjusted Odds Ratio for COPD according to Time to First Cigarette (TTFC) among current smokers in PLCO.