TABLE 5.
Colorectal cancer and adenoma according to folate intake by other factors1
| Folate intake categories (μg/d) |
||||||
| Variables | 1 | 2 | 3 | 4 | P for trend2 | P for heterogeneity3 |
| Colorectal cancer4 | ||||||
| Baseline total folate (μg/d) | <250 | 250 to <400 | 400 to <600 | ≥600 | — | — |
| Alcohol | ||||||
| Nondrinkers (n = 373) | 1.00 | 0.80 (0.60, 1.06) | 0.70 (0.29, 1.67) | 0.88 (0.62, 1.26) | 0.99 | 0.94 |
| <15 g/d, 1 drink (n = 1223) | 1.00 | 0.91 (0.73, 1.13) | 0.89 (0.69, 1.15) | 0.78 (0.64, 0.96) | 0.05 | — |
| ≥15 g/d (n = 457) | 1.00 | 1.02 (0.77, 1.34) | 0.88 (0.51, 1.52) | 0.87 (0.61, 1.23) | 0.23 | — |
| Family history of colorectal cancer | ||||||
| No family history (n = 1581) | 1.00 | 0.94 (0.77, 1.14) | 0.90 (0.76, 1.05) | 0.82 (0.69, 0.99) | 0.07 | 0.77 |
| Family history (n = 472) | 1.00 | 0.82 (0.63, 1.07) | 0.75 (0.42, 1.33) | 0.78 (0.55, 1.10) | 0.24 | — |
| Baseline natural folate (μg/d) | <200 | 200 to <300 | 300 to <400 | ≥400 | — | — |
| Multivitamin use | ||||||
| Never (n = 601) | 1.00 | 0.94 (0.71, 1.24) | 0.85 (0.59, 1.22) | 0.97 (0.44, 2.14) | 0.70 | 0.97 |
| Past (n = 432) | 1.00 | 0.83 (0.63, 1.09) | 0.97 (0.69, 1.36) | 0.81 (0.47, 1.41) | 0.62 | — |
| Current (n = 962) | 1.00 | 0.95 (0.79, 1.14) | 1.09 (0.87, 1.36) | 0.96 (0.69, 1.34) | 0.76 | — |
| Colorectal adenoma5 | ||||||
| Simple updated total folate (μg/d) | <250 | 250 to <400 | 400 to <600 | ≥600 | — | — |
| Alcohol | ||||||
| Nondrinkers (n = 781) | 1.00 | 1.27 (0.95, 1.69) | 1.24 (0.91, 1.69) | 0.93 (0.69, 1.26) | 0.01 | 0.70 |
| <15 g/d (n = 3234) | 1.00 | 0.87 (0.74, 1.01) | 0.90 (0.77, 1.06) | 0.72 (0.62, 0.85) | <0.001 | — |
| ≥15 g/d (n = 1092) | 1.00 | 0.99 (0.71, 1.39) | 1.07 (0.80, 1.41) | 0.86 (0.65, 1.14) | 0.03 | — |
| Family history of colorectal cancer | ||||||
| No family history (n = 3815) | 1.00 | 0.98 (0.85, 1.13) | 0.99 (0.85, 1.15) | 0.81 (0.70, 0.94) | <0.001 | 0.39 |
| Family history (n = 1292) | 1.00 | 0.90 (0.72, 1.14) | 1.03 (0.81, 1.32) | 0.72 (0.57, 0.91) | <0.001 | — |
| Simple updated natural folate (μg/d) | <200 | 200 to <300 | 300 to <400 | ≥400 | — | — |
| Multivitamin use | ||||||
| Never (n = 1455) | 1.00 | 0.94 (0.80, 1.12) | 0.78 (0.62, 0.98) | 0.76 (0.53, 1.09) | 0.04 | 0.86 |
| Past (n = 1220) | 1.00 | 0.99 (0.80, 1.21) | 1.01 (0.79, 1.30) | 0.81 (0.53, 1.22) | 0.07 | — |
| Current (n = 2961) | 1.00 | 1.03 (0.76, 1.39) | 0.95 (0.66, 1.36) | 0.73 (0.56, 0.95) | <0.001 | — |
n, number of cases. Unless otherwise indicated, all values are pooled multivariate relative risks; 95% CIs in parentheses. We used the baseline folate intake for colorectal cancer and simple updated intake for colorectal adenoma because we considered those as the relevant timing of intakes on the basis of the main results in Tables 2 and 3.
Two-sided; calculated by using Wald's test statistic.
For the highest category. Two-sided and calculated by using Wald's test statistic.
A Cox proportional hazards model was used and adjusted for age, calendar year, pack-years of smoking before age 30 y, physical activity, aspirin dose, height, BMI, family history of colorectal cancer in parents and siblings, menopausal status and hormone therapy use, history of endoscopy, red-meat intake, alcohol intake, calcium intake from foods, and total energy intake.
A logistic regression model was used and adjusted for age, endoscopy before baseline, recent endoscopy year, pack-years of smoking before age 30 y, physical activity, aspirin dose, height, BMI, family history of colorectal cancer in parents and siblings, menopausal status and hormone therapy use, red-meat intake, alcohol intake, calcium intake from foods, total energy intake, and indication for endoscopy.