Table 1.

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

	Placebo (n=30)	β-Carotene (n=52)	p-value†
Age at randomization, years	62 (56–64)	60 (56–65)	0.93
Age at diagnosis, years	65 (61–67)	64 (60–68)	0.98
Intervention time, days‡	1689 (601–2079)	1716 (981–2243)	0.30
Cigarettes / day at baseline	20 (15–25)	20 (19-30)	0.55
Years smoked at baseline	41 (38–47)	41 (37–45)	0.90
Smoking cessation§	5 (17)	9 (17)	0.95
Alcohol intake at baseline, g/day	10.7 (5.5–18.6)	10.7 (2.7–34.5)	0.71
Baseline serum β-carotene, µg/L	167 (109–282)	180 (102–247)	0.95
On-study serum β-carotene, µg/L║	150 (118–236)	2804 (1785–3375)	<0.0001
Histology			0.81
Squamous cell carcinoma	14 (47)	26 (50)
Adenocarcinoma	11 (37)	14 (27)
Other	5 (16)	12 (23)

^*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 year during the trial

^║Measured 3 years after randomization