TABLE 3.
Association of urinary isothiocyanate (ITC) concentrations with colorectal cancer risk by glutathione S-transferase genotype: Shanghai Women's Health Study (1997–2005)
| Tertile of urinary ITCs (nmol/mg creatinine) |
|||||
| 1 (<0.95) | 2 (0.95–2.98) | 3 (>2.98) | P for trend | P for interaction | |
| Overall | |||||
| No. of cases/controls | 117/413 | 105/414 | 100/427 | — | — |
| Crude OR (95% CI) | 1.00 | 0.88 (0.65, 1.20) | 0.81 (0.58, 1.12) | 0.20 | — |
| Multivariable OR (95% CI)1 | 1.00 | 0.87 (0.63, 1.18) | 0.77 (0.55, 1.07) | 0.12 | — |
| GSTM1 null | |||||
| No. of cases/controls | 77/242 | 58/242 | 54/245 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 0.75 (0.50, 1.11) | 0.66 (0.44, 1.00) | 0.04 | 0.10 |
| GSTM1 present | |||||
| No. of cases/controls | 40/168 | 47/170 | 46/180 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 1.22 (0.75, 1.99) | 1.12 (0.68, 1.83) | 0.68 | — |
| GSTT1 null | |||||
| No. of cases/controls | 66/199 | 50/215 | 48/196 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 0.66 (0.42, 0.99) | 0.67 (0.44, 1.05) | 0.07 | 0.33 |
| GSTT1 present | |||||
| No. of cases/controls | 51/211 | 55/197 | 52/229 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 1.13 (0.73, 1.75) | 0.92 (0.59, 1.44) | 0.71 | — |
| GSTM1 and GSTT1 null | |||||
| No. of cases/controls | 40/105 | 32/119 | 24/102 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 0.61 (0.35, 1.08) | 0.51 (0.27, 0.95) | 0.03 | <0.05 |
| GSTM1 or GSTT1 null | |||||
| No. of cases/controls | 63/231 | 44/219 | 54/237 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 0.75 (0.48, 1.16) | 0.84 (0.55, 1.28) | 0.40 | — |
| GSTM1 and GSTT1 present | |||||
| No. of cases/controls | 14/74 | 29/74 | 22/86 | — | — |
| Multivariable OR (95% CI)2 | 1.00 | 2.16 (0.98, 4.78) | 1.25 (0.56, 2.78) | 0.73 | — |
Odds ratios (ORs) were estimated by using multivariable conditional logistic regression models, adjusted for age, education, household income, physical activity, cigarette smoking, alcohol consumption, BMI, family history of colorectal cancer, and intakes of total energy, fruit, noncruciferous vegetables, red meat, and calcium.
ORs were estimated by using multivariable unconditional logistic regression model, adjusted for all covariates included in the model above and all matching variables including menopausal status at sample collection, time of sample collection, time interval (h) between last meal and sample collection, antibiotic use in the past week, and time interval (y) between sample collection and ITC measurement.