Table 3:
Colorectal tumor marker Ki67 expression (% positive) by consumption of dietary folate, use of folic acid supplements, total folate (including folate from diet and supplements) and alcohol consumption a stratified by CRC tumor site. Data presented as β (95% CI) relative to the reference level
| Proximal tumors b
(n = 114) |
Distal tumors b
(n = 122) |
|||||
|---|---|---|---|---|---|---|
| N |
Model 1
c β (95% CI) |
Model 2
d β (95% CI) |
N |
Model 1
c β (95% CI) |
Model 2
d β (95% CI) |
|
| Dietary folate (DFE) a | ||||||
| Q1 (125.3–369.5) | 31 | 20.8 (mean) - Ref e | 22.3 (mean) - Ref e | 29 | 20.4 (mean) - Ref e | 22.4 (mean) - Ref e |
| Q2 (372.8–586.1) | 27 | −0.2 (−7.2–6.8) | 1.2 (−6.0–8.3) | 32 | 2.8 (−5.2–10.7) | 3.4 (−4.5–11.3) |
| Q3 (586.3–854.8) | 27 | −0.5 (−8.5–7.4) | −0.3 (−8.5–7.8) | 32 | 3.3 (−5.8–12.4) | 3.6 (−5.8–12.9) |
| Q4 (859.9–3146.0) | 29 | −5.0 (−16.7–6.7) | −5.3 (−17.3–6.7) | 29 | 4.0 (−8.5–16.4) | 3.6 (−9.0–16.3) |
| β (95% CI) per 200 DFE | 114 | 0.8 (−1.4–3.0) | 1.1 (−1.3–3.4) | 122 | 0.5 (−2.3–3.3) | 1.3 (−1.5–4.2) |
| P-trend f | .47 | .37 | .73 | .36 | ||
| Folic acid supplements a | ||||||
| < 1x per week | 79 | 20.0 (mean) - Ref e | 21.7 (mean) - Ref e | 84 | 21.3 (mean) - Ref e | 23.1 (mean) - Ref e |
| ≥ 1x per week | 35 | −1.6 (−7.0–3.7) | −1.4 (−7.1–4.3) | 38 | 5.3 (−0.7–11.3) | 7.5 (1.2–13.8) |
| P-value f | .55 | .62 | .08 | .02 | ||
| Total folate (DFE) a,g | ||||||
| Q1 (125.7–429.9) | 28 | 22.5 (mean) - Ref e | 24.1 (mean) - Ref e | 30 | 20.6 (mean) - Ref e | 21.7 (mean) - Ref e |
| Q2 (436.6–793.3) | 30 | −1.1 (−8.0–5.9) | 0.2 (−6.9–7.3) | 30 | 0.6 (−7.4–8.7) | 1.5 (−6.6–9.6) |
| Q3 (797.1–1256.2) | 24 | −6.3 (−14.3–1.8) | −7.4 (−15.5–0.7) | 34 | 3.7 (−4.8–12.2) | 5.4 (−3.3–14.1) |
| Q4 (1258.3–3146.0) | 32 | −5.2 (−13.7–3.2) | −4.5 (−13.3–4.2) | 28 | 5.1 (−5.2–15.5) | 8.5 (−2.6–19.6) |
| β (95% CI) per 200 DFE | 114 | −0.1 (−1.2–1.0) | 0.0 (−1.2–1.2) | 122 | 0.9 (−0.6–2.4) | 1.6 (0.0–3.3) |
| P-trend f | .82 | .98 | .23 | .05 | ||
| Alcohol a,h | ||||||
| Non-drinker | 63 | 18.7 (mean) - Ref e | 19.4 (mean) - Ref e | 64 | 21.0 (mean) - Ref e | 22.1 (mean) - Ref e |
| Light drinker | 34 | 0.3 (−5.5–6.1) | 0.0 (−6.0–6.0) | 42 | 2.0 (−4.0–8.0) | 0.4 (−5.8–6.6) |
| Heavy drinker | 17 | 5.0 (−2.7–12.8) | 5.4 (−2.6–13.4) | 16 | 10.0 (1.5–18.5) | 10.4 (1.6–19.1) |
| P-value (heavy vs. non) f | .20 | .18 | .02 | .02 | ||
Abbreviation: CI – confidence interval; CRC – colorectal cancer; DFE – dietary folate equivalent
Consumption of alcohol and folate from diet and supplements was assessed for the year prior to enrollment.
Proximal colon tumors include ICD-O-3 codes C180-C185. Distal colon or rectal tumors include ICD-O-3 codes C186, C187, C199, and C209.
Model 1: Adjusted for age at enrollment, race, sex, and total energy intake (kcal/day)
Model 2: Further adjusted for total folate (alcohol model only), alcohol (folate models only), and tumor stage
Values for the reference group are the mean value for quartile 1 adjusted for the covariates included in the statistical model.
For the interaction with CRC tumor site, all p-interaction > .05
Incudes dietary folate/folic acid and folic acid from supplements
Non-drinker: 0 drinks per day; Light-drinker: alcohol consumption > 0 and < 1 drink/day for women, < 2 drink/day for men; Heavy drinker: ≥ 1 drink/day for women, ≥ 2 drink/day for men