(liters) for non-exposed and ETS exposed subjects stratified by genotype for the two genotyped SNPs rs1147611 and rs156699. GSTO1 SNP rs1147611 (upper row) and GSTO2 SNP rs156699 (lower row). The analysis was adjusted for sex, current, ex-smoking, packyears smoked, and centered for mean age, height and weight. A: In utero ETS (no/yes). B: daily ETS exposure (</≥1 hr). C: ETS exposure at the workplace (no/yes).