TABLE 2.
Relative risks and 95% confidence intervals (CIs) of colorectal cancer according to quintile intakes of folate and vitamin B6 in the Women's Health Study
| Quintile Intake | ||||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | P trend | |
| Total folate | ||||||
| Intake* (μg/day) | <259 | 259-317 | 317-392 | 392-614 | ≥614 | |
| No. cases | 38 | 46 | 40 | 44 | 52 | |
| Relative Risk† | 1.00 | 1.13 | 0.93 | 1.01 | 1.17 | 0.46 |
| 95% CI | 0.74, 1.74 | 0.60, 1.45 | 0.65, 1.56 | 0.77, 1.78 | ||
| Relative Risk‡ | 1.00 | 1.10 | 0.91 | 0.97 | 1.16 | 0.46 |
| 95% CI | 0.71, 1.70 | 0.58, 1.44 | 0.62, 1.52 | 0.76, 1.79 | ||
| Dietary folate | ||||||
| Intake* (μg/day) | ≤244 | 244-288 | 288-329 | 329-385 | ≥385 | |
| No. cases | 48 | 32 | 50 | 48 | 42 | |
| Relative Risk† | 1.00 | 0.63 | 0.93 | 0.86 | 0.72 | 0.34 |
| 95% CI | 0.40, 0.98 | 0.62, 1.38 | 0.58, 1.29 | 0.47, 1.09 | ||
| Relative Riskठ| 1.00 | 0.62 | 0.89 | 0.83 | 0.67 | 0.21 |
| 95% CI | 0.40, 0.98 | 0.59, 1.34 | 0.55, 1.26 | 0.43, 1.03 | ||
| Dietary folate (excluding folate supplement users) | ||||||
| Intake* (μg/day) | ≤244 | 244-288 | 288-329 | 329-385 | ≥385 | |
| No. cases | 35 | 21 | 35 | 30 | 20 | |
| Relative Risk† | 1.00 | 0.59 | 0.97 | 0.80 | 0.52 | 0.07 |
| 95% CI | 0.34, 1.01 | 0.61, 1.55 | 0.49, 1.31 | 0.30, 0.91 | ||
| Relative Riskठ| 1.00 | 0.58 | 0.92 | 0.75 | 0.46 | 0.02 |
| 95% CI | 0.34, 1.00 | 0.57, 1.48 | 0.45, 1.25 | 0.26, 0.81 | ||
| Total vitamin B6 | ||||||
| Intake (mg/day) | <1.78 | 1.78-2.09 | 2.10-2.52 | 2.53-3.99 | ≥4.00 | |
| No. cases | 46 | 39 | 30 | 44 | 61 | |
| Relative Risk† | 1.00 | 0.82 | 0.59 | 0.85 | 1.14 | 0.06 |
| 95% CI | 0.53, 1.26 | 0.37, 0.93 | 0.56, 1.29 | 0.78, 1.67 | ||
| Relative Risk‡ | 1.00 | 0.84 | 0.58 | 0.85 | 1.14 | 0.07 |
| 95% CI | 0.55, 1.30 | 0.36, 0.93 | 0.55, 1.30 | 0.77, 1.69 | ||
| Dietary vitamin B6 | ||||||
| Intake (mg/day) | <1.69 | 1.69-1.91 | 1.92-2.12 | 2.13-2.39 | ≥2.40 | |
| No. cases | 47 | 47 | 42 | 32 | 52 | |
| Relative Risk† | 1.00 | 0.93 | 0.82 | 0.61 | 0.88 | 0.29 |
| 95% CI | 0.62, 1.40 | 0.54, 1.25 | 0.39, 0.96 | 0.59, 1.31 | ||
| Relative Riskठ| 1.00 | 0.98 | 0.86 | 0.61 | 0.84 | 0.18 |
| 95% CI | 0.65, 1.48 | 0.56, 1.31 | 0.39, 0.97 | 0.56, 1.27 | ||
| Dietary vitamin B6 (excluding vitamin B6 supplement users) | ||||||
| Intake (mg/day) | <1.69 | 1.69-1.91 | 1.92-2.12 | 2.13-2.39 | ≥2.40 | |
| No. cases | 34 | 33 | 25 | 19 | 28 | |
| Relative Risk† | 1.00 | 0.93 | 0.70 | 0.54 | 0.72 | 0.07 |
| 95% CI | 0.58, 1.50 | 0.42, 1.18 | 0.31, 0.94 | 0.44, 1.20 | ||
| Relative Risk‡ | 1.00 | 0.99 | 0.74 | 0.54 | 0.69 | 0.047 |
| 95% CI | 0.61, 1.61 | 0.44, 1.26 | 0.31, 0.96 | 0.41, 1.15 | ||
| Methionine | ||||||
| Intake (g/day) | <1.61 | 1.61-1.81 | 1.82-2.00 | 2.01-2.23 | ≥2.24 | |
| No. cases | 59 | 45 | 34 | 37 | 45 | |
| Relative Risk† | 1.00 | 0.83 | 0.63 | 0.72 | 0.88 | 0.36 |
| 95% CI | 0.56, 1.23 | 0.41, 0.96 | 0.48, 1.09 | 0.60, 1.30 | ||
| Relative Riskठ| 1.00 | 0.90 | 0.68 | 0.77 | 0.89 | 0.43 |
| 95% CI | 0.60, 1.33 | 0.44, 1.04 | 0.51, 1.18 | 0.60, 1.32 | ||
*
Some values were overlapped due to rounding.
†
Models were adjusted for age and randomized treatment assignment.
‡
Multivariate models were adjusted for age, randomized treatment assignment, body mass index, family history of colorectal cancer in a first-degree relative, history of colon polyps, physical activity, smoking status, red meat intake, alcohol consumption, total energy intake, menopausal status, baseline PMH use, and baseline aspirin use.
§
Multivariate models were additionally adjusted for the use of multivitamin supplements.