Table 3.
Folate and Colon / Rectal Cancer.
| Reference | Study | # Cases | # Controls | Outcomes | Comment |
|---|---|---|---|---|---|
| [195] | Case / control USA | 35 | 64 | Folate supplementation = 62% lower incidence of neoplasia | result not SS |
| [196] | Case / control NY state | 800 | Matched neighbor-hood controls | ↑Folate = ↓rectal cancer, OR = 0.5 men, OR = 0.31, women Folate no effect for colon cancer | SS |
| [197] | Case / control Majorca, Spain | 286 | 498 | Colon cancer related to total calories, cholesterol, animal protein, low fiber, low folic acid | . |
| [198] | Case / Control Wash. state | 424 | 414 | ↑Alcohol = ↑cancer risk; ↑fiber = ↓risk; no relation to folate intake | 2.5X risk for 30 g/day alcohol |
| [199] | Nurses' Health Study & Health Professionals Follow-up Study | 564 women, 331 men | ↑folate = ↓risk of colorectal adenoma: ORwomen = 0.66, ORmen = 0.63 | ||
| [200] | Case / Control, Italy | 1,326 | 2,024 hospital controls | Protective trends for β-carotene, ascorbic acid, vit E, and folate (OR = 0.32, 0.40, 0.60, 0.52, respectively) | Similar for colon and rectal cancer |
| [201] | US male health professional cohort | 205 | ↑Alcohol = ↑colon cancer (OR = 2.07 for ≥ 2 drinks/day; folate weakly protective; ↑Alcohol + ↓folate = ↑colon cancer risk (OR = 3.30) | ||
| [202] | α-tocopherol, β-carotene study cohort of smokers | 144 | 276 | ↑dietary folate = ↓colon cancer (OR = 1.0, 0.40, 0.34, 0.51, P-trend = 0.15); | alcohol intake increased risk |
| [203] | Case control, population based | Composite dietary profile (alcohol intake, methionine, folate, vit B12, B6) trend of increasing risk for high risk group | Marginal SS | ||
| [204] | Nurses' Health Study | 442 | ↑folate intake = ↓colon cancer (OR = 0.69); long-term use of multi-vitamins beneficial | Folate intake includes multi-vitamins | |
| [205] | NYU Women's Health Study | 105 | 523 | ↑folate = ↓colorectal cancer risk (OR = 0.52, P-trend = 0.04 | Alcohol increased risk |
| [206] | NHANES I Epidemiologic Follow-up Study | ↑folate = ↓colon cancer (ORmen = 0.40, P-trend = 0.03; ↑alcohol, ↓folate = ↑colon cancer (ORmen = 2.67 | Results not stat. signif in women | ||
| [207] | Nurses' Health Study | 535 | ↑folate intake = ↓colon cancer in women with family history (OR = 0.48) | Folate effect greater in women with family history | |
| [208] | Canadian National Breast Screening Study | 295 | 5,334 | ↑folate = ↓colorectal cancer (OR = 0.6, P-trend = 0.25 | Results not SS |
| [209] | Prospective cohort in The Netherlands | 1,171 | Rectal: OR, men 0.66, women no trend | Trends SS only in men | |
| [210] | Case / Control Italy | 1,953 | 4,154 | ↑folate = ↓colorectal cancer (OR = 0.72) | Population drinks alcohol regularly |
| [211] | Iowa Women's health Study | 721 | ↑folate + (↑B12 or ↑B6) = ↓colon cancer (OR = 0.59, 0.65, respectively | Nutrients not independent, alcohol increases risk | |
| [212] | Case / Control NC state | 613 | 996 | ↑β-carotene, vit C, calcium = 40–60 % ↓risk colon cancer in whites; in African Americans ↑ vit C and E = 50–70% ↓risk colon cancer; no relation to folate to cancer risk | Colon cancer rates higher in Aftrican Americans in NC; due to less UV light absorption with dark skin? |
| [213] | Wheat Bran Fiber trial, test for recurrence of adenoma polyps | 1,014 men and women | ↑homocysteine = ↑risk (OR = 0.69); ↑plasma folate = ↓risk (OR = 0.66) ↑folate or B6 intake (diet + supplements) = ↓risk (OR = 0.61 | SS; cut-off for highest quartile is 664 μg/day (way above RDA) |
SS = statistically significant