Table 4.

Pooled multivariate relative risks^a of colon cancer for categories of total vitamin A, C, and E intakes by tumor site

Total vitamin A	Categoriesb						p-value, test for trend	p-value, test for between-studies heterogeneityc	p-value, test for between-studies heterogeneity due to sexc	p-value, test for common effects by tumor sitec
	≤1,000 (μg/day)	>1,000–1,500	>1,500–2,000	>2,000–2,500	>2,500–4,000	>4,000
Case (n)	598/497d	580/414	347/235	270/183	405/326	192/150
Proximal	1.00	0.96 (0.84–1.09)	0.96 (0.82–1.13)	0.94 (0.80–1.12)	0.85 (0.72–0.99)	0.87 (0.71–1.07)	0.02	0.94	0.63	0.66
Distal	1.00	0.84 (0.72–0.97)	0.80 (0.67–0.97)	0.82 (0.67–1.00)	0.85 (0.67–1.09)	0.83 (0.65–1.05)	0.15	0.80	0.56

Total vitamin C	Categoriesb						p-value, test for trend	p-value, test for between-studies heterogeneityc	p-value, test for between-studies heterogeneity due to sexc	p-value, test for common effects by tumor sitec
	≤100 (mg/day)	>100–150	>150–200	>200–250	>250–600	>600
Case (n)	539/418	493/391	399/306	282/176	350/264	329/219
Proximal	1.00	0.85 (0.71–1.00)	0.94 (0.76–1.16)	1.08 (0.82–1.41)	0.85 (0.71–1.01)	0.85 (0.70–1.05)	0.09	0.31	0.74	0.34
Distal	1.00	0.92 (0.79–1.07)	0.98 (0.76–1.25)	0.89 (0.71–1.11)	0.83 (0.68–1.02)	0.72 (0.55–0.93)	0.01	0.19	0.97

Total vitamin E	Categoriesb					p-value, test for trend	p-value, test for between-studies heterogeneityc	p-value, test for between-studies heterogeneity due to sexc	p-value, test for common effects by tumor sitec
	≤6 (mg/day)	>6–9	>9–25	>25–200	>200
Case (n)	287/241	656/459	872/690	301/214	276/170
Proximal	1.00	0.96 (0.80–1.15)	0.83 (0.70–0.97)	0.81 (0.63–1.05)	0.82 (0.67–0.99)	0.14	0.49	0.24	0.58
Distal	1.00	0.90 (0.74–1.09)	0.97 (0.80–1.16)	0.99 (0.75–1.32)	0.73 (0.58–0.92)	0.02	0.63	0.46

^aAdjusted for same covariates listed in Table 2 footnote c

^bThe following studies were excluded from a category because these studies did not have any cases in that category; the participants who were not cases who would have been in that category were included in the next highest category. The Alpha-Tocopherol Beta-Carotene Cancer Prevention Study was excluded from the highest category of total vitamins A and E intake in both the proximal and the distal colon cancer analyses. The Alpha-Tocopherol Beta-Carotene Cancer Prevention Study was also excluded from the >250–600 mg/d category of total vitamin C intake in the proximal colon cancer analyses, the >25–200 mg/d category of total vitamin E intake in the proximal colon cancer analyses, and the >200–250 mg/d category of total vitamin C intake in the distal colon cancer analyses. Both the male and the female cohorts of the Netherlands Cohort Study were excluded from the highest category of total vitamins A, C, and E intake in both the proximal and distal colon cancer analyses. The male cohort of the Netherlands Cohort Study was also excluded from the >2,000–2,500 and >2,500–4,000 μg/day categories of total vitamin A intake in the distal colon cancer analyses. The Women’s Health Study was excluded from the highest category of total vitamin C intake in the proximal colon cancer analyses and of total vitamin A intake in the distal colon cancer analyses. The New York University Women’s Health Study was excluded from the distal colon cancer analyses for total vitamin C intake and total vitamin E intake because the study had no cases in the reference category. Both the male and the female cohorts of the New York State Cohort were excluded from the >25–200 mg/d category of total vitamin E intake in both the proximal and distal colon cancer analyses

^cFor the highest category

^dCases in proximal/distal colon