Table 1.

Lifestyle and clinical characteristics of lung cancer cases according to trial intervention group

Placebo (n = 30)β-Carotene (n = 52)P*
Age at randomization, y62 (56-64)60 (56-65)0.93
Age at diagnosis, y65 (61-67)64 (60-68)0.98
Intervention time, d1,689 (601-2,079)1,716 (981-2,243)0.30
Cigarettes per day at baseline20 (15-25)20 (19-30)0.55
Years smoked at baseline41 (38-47)41 (37-45)0.90
Smoking cessation5 (17)9 (17)0.95
Alcohol intake at baseline, g/d10.7 (5.5-18.6)10.7 (2.7-34.5)0.71
Baseline serum β-carotene, μg/L167 (109-282)180 (102-247)0.95
On-study serum β-carotene, μg/L§150 (118-236)2,804 (1,785-3,375)<0.0001
Histology0.81
    Squamous cell carcinoma14 (47)26 (50)
    Adenocarcinoma11 (37)14 (27)
    Other5 (16)12 (23)

NOTE: Data are median (interquartile range) for continuous variables and number (percent) for categorical variables.

  • *From the Wilcoxon rank-sum test for continuous variables and Fisher's exact test for categorical variables.

  • Time from baseline to last study visit.

  • Defined as having stopped smoking for at least 1 y during the trial.

  • §Measured 3 y after randomization.