. 2013 Feb 1;8(2):e54561. doi: 10.1371/journal.pone.0054561

Table 4. Association between quartiles of choline intake and lung cancer risk.

Models		Quartiles of choline intake				p^** _trend
		1	2	3	4
	Case n (%)	809 (52.57)	640 (46.68)	638 (46.60)	734 (50.10)
	Control n (%)	730 (47.43)	731 (53.32)	731 (53.40)	731 (49.90)
Overall
Reduced^a	OR (95% CI)	1.00	0.77 (0.66–0.90)	0.76 (0.66–0.89)	0.89 (0.77–1.03)	0.118
	P^* _overall	0.001
Complete^b	OR (95% CI)	1.00	0.79 (0.68–0.93)	0.82 (0.70–0.96)	0.92 (0.78–1.07)	0.334
	P^* _overall	0.017
Stratified by smoking status
Never Smokers
Reduced^c	OR (95% CI)	1.00	0.72 (0.51–1.01)	0.72 (0.51–1.02)	0.71 (0.50–1.01)	0.070
	P^* _overall	0.150
Complete^d	OR (95% CI)	1.00	0.70 (0.49–0.99)	0.73 (0.51–1.04)	0.68 (0.47–0.98)	0.058
	P^* _overall	0.118
Former Smokers
Reduced^c	OR (95% CI)	1.00	0.86 (0.68–1.08)	0.88 (0.70–1.11)	1.02 (0.81–1.28)	0.843
	P^* _overall	0.376
Complete^d	OR (95% CI)	1.00	0.93 (0.72–1.19)	0.98 (0.76–1.26)	1.13 (0.88–1.44)	0.299
	P^* _overall	0.471
Current Smokers
Reduced^c	OR (95% CI)	1.00	0.71 (0.55–0.91)	0.66 (0.52–0.84)	0.84 (0.67–1.06)	0.113
	P^* _overall	0.004
Complete^d	OR (95% CI)	1.00	0.72 (0.55–0.94)	0.73 (0.56–0.95)	0.86 (0.67–1.11)	0.260
	P^* _overall	0.047

Adjusted for sex, race/ethnicity, age (continuous), smoking status, total caloric intake.

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake, family cancer history, dust exposure, second-hand smoke, emphysema, hay fever, smoking status, asthma, addiction index, alcohol, time since smoking cessation.

Adjusted for sex, race/ethnicity, age (continuous), total caloric intake.

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake, family cancer history, dust exposure, second-hand smoke, emphysema, hay fever, asthma, addiction index, alcohol, time since smoking cessation.

p-value, chi-square test using quartiles of choline intake as categorical variable.

^**

p-value, test for linear trend using quartiles of choline intake as continuous variable.