Table 4.

Multivariable generalized estimating equation logistic regression model* odds ratios for current smoking status (yes vs. no) and screening result, stratified by randomization arm

Screening result	Chest x-ray arm (n = 7239) Odds ratio (95% CI) P	Computed tomography arm (n = 7382) Odds ratio (95% CI) P
Normal	Referent group	Referent group
Minor abnormality, not suspicious for lung cancer	0.860 (0.796 to 0.930) <.001	1.009 (0.906 to 1.123) .88
Major abnormality, not suspicious for lung cancer	0.809 (0.651 to 1.005) .06	0.865 (0.742 to 1.008) .06
Positive, suspicious for lung cancer, but stable from previous screen	0.719 (0.548 to 0.942) .02	0.836 (0.727 to 0.962) .01
Positive, suspicious for lung cancer	0.714 (0.642 to 0.817) <.001	0.685 (0.601 to 0.781) <.001

* The model covariables included age, race/ethnicity, education, marital status, body mass index (kg/m²), family history of lung cancer, smoking intensity and duration, exposure to secondhand smoke in the home, regular pipe or cigar smoking, study year, and study center as described in Table 3. Smoking status data were for years 1, 2, and 3 after baseline. The screening results were lagged to 1 year before smoking status and came from baseline and years 1 and 2 after baseline, respectively. Individuals who developed lung cancer in the follow-up period were excluded from analysis. CI = confidence interval.