Table 4.

Odds Ratios and 95% Confidence Intervals for the Association Between a GSTP1 Exon 5 (Ile105Val, 313A → 313G) Polymorphism (Ile/Val and Val/Val vs. Ile/Ile) and Lung Cancer in Whites in the Pooled Analysis, Stratified by Pack-years of Smoking

Smoking Status	No. of Cases		No. of Controls		ORa	95% CI	P Trend	P Valueb
	Ile/Ile	Ile/Val or Val/Val	Ile/Ile	Ile/Val or Val/Val
Nonsmoker	204	251	656	692	1.17	0.92, 1.50	0.16c	Reference
1–28 pack-years	279	386	459	539	1.23	1.00, 1.52		0.09
28.01–48 pack-years	490	557	292	334	1.01	0.82, 1.24		0.57
≥48.01 pack-years	505	592	228	329	0.83	0.67, 1.03	0.05d	0.03

Abbreviations: CI, confidence interval; GSTP1, glutathione S-transferase pi gene; Ile, isoleucine; OR, odds ratio; Val, valine.

^aAdjusted for study ID (an assigned study identifier for each study population), age, and sex.

^bP value for nonsmokers and with Ile/Ile as the reference group, adjusted for study ID, age, and sex.

^cP-value test for trend among all 4 categories.

^dP-value test for trend among smokers only.