Table 3.

ORs of breast cancer associated with GST genotypes (GSTM1, GSTT1, and GSTP1) stratified by smoking exposure (A: ever/never smoking; B: pack-years smoked)

Cases/controlsOR* (95% CI)Cases/controlsOR* (95% CI)Cases/controlsOR* (95% CI)Interaction P
ATotalNever SmokersEver Smokers
GSTM1+347/5281.0199/3161.0148/2121.0
GSTM1361/5950.91 (0.75–1.10)202/3650.85 (0.66–1.09)159/2301.00 (0.74–1.34)0.44
GSTT1+286/4951.0186/3211.0100/1741.0
GSTT1101/1461.17 (0.87–1.57)65/1011.06 (0.74–1.53)36/451.39 (0.84–2.30)0.41
GSTP1wt85/1651.057/1171.028/481.0
GSTP1het55/1310.81 (0.54–1.23)36/920.80 (0.49–1.32)19/390.84 (0.41–1.72)
GSTP1mut9/260.67 (0.30–1.50)6/190.65 (0.25–1.71)3/70.73 (0.18–3.07)0.99
BTotal<27 Pack-Years≥27 Pack-Years
GSTM1+120/1821.071/1011.049/811.0
GSTM1140/1981.09 (0.79–1.50)81/881.33 (0.86–2.05)59/1100.84 (0.52–1.37)0.16
GSTT1+73/1321.042/601.031/721.0
GSTT127/341.43 (0.80–2.56)19/102.69 (1.13–6.37)8/240.79 (0.32–1.96)0.051
GSTP1wt28/481.017/171.011/311.0
GSTP1het19/390.84 (0.41–1.72)14/200.70 (0.27–1.83)5/190.74 (0.22–2.47)
GSTP1mut3/70.73 (0.18–3.07)2/50.40 (0.07–2.35)1/21.41 (0.12–17.12)0.73
  • NOTE: Abbreviations: wt, wild-type; het, heterozygous mutant; hom, homozygous mutant.

  • * ORs were adjusted for study center, except for the analysis of GSTP1, because both smoking and GSTP1 genotype were assessed only in one study.

  • The total number of cases and controls in these columns refers to subjects with available information on smoking habits.

  • Reference category.