Table 3 Folate and Colon / Rectal Cancer.

[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: OR_women = 0.66, OR_men = 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 (OR_men = 0.40, P-trend = 0.03; ↑alcohol, ↓folate = ↑colon cancer (OR_men = 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)