Page 314 - Vitamin D and Cancer

13 Vitamin D and Colorectal Cancer 301

Table 13.1 Case–control studies (2000–2007): vitamin D status and adenomatous polyps
Year Author Population OR (CI)
2000 Platz [36] Nurses Health Study 0.34 (0.16–0.75) (1st vs 4
quintile)
2001 Peters [35] Nat Naval Med Center 0.74 (0.60–0.92) (10 ng/mL inc)
2001 Levine [33] 0.74 (0.49–1.09)
2003 Lieberman [39] 13 VA 0.94 (0.90–0.99)
2004 Hartman [38] Polyp Prevention trial 0.82 (0.68–0.99) (supplemental
Vit D)
2007 Oh [37] Nurses Health Study 0.79 (0.63–0.99)
2007 Miller [34] Diet and Health Study III 0.51 (0.27–0.98)

adenoma-free controls. Blood samples, in contrast to the other three trials, were
collected several years after the endoscopic procedure. No difference in the median
levels of 25-D by RIA were seen between cases and controls. However, in subjects
3
with a consistent vitamin D intake across the years, an inverse association between
25-D and risk of adenomatous polyps was noted (OR of 0.64, 0.41, and 0.34 for
3
2nd, 3rd, and 4th quartiles when compared to the 1st quartile).
These case–control studies suggest a potential protective effect of higher levels
of plasma 25-D against polyp formation. These findings are supported further by
3
several other epidemiological studies associating an increased dietary vitamin D
with a lower risk of colorectal adenomas [35–39].

13.1.2.4 Vitamin D Status and Colorectal Cancer

Vitamin D insufficiency, assessed by 25-D serum levels, has been associated with
3
an increased risk of colorectal cancer in several case-control studies (Table 13.2).
Garland et al. performed a case–control study based on a volunteer population with
donated blood samples in 1974 who were subsequently followed for eight years
[40]. Thirty-four colorectal cancer cases were matched to 67 controls by age, race,
sex, and month of blood draw. 25-D serum levels were assayed by HPLC. The risk
3
of colorectal cancer was reduced by 75% in the third quintile and by 80% in the
fourth quintiles of serum 25-D . The odds of getting colorectal cancer was 70% less
3
for patients with 25-D levels ³ 20 ng/mL compared to <20 ng/mL. These results
3
were not confirmed in another case–control study from the same base population
[41]. A Finnish case–control study matched 146 newly diagnosed colon cancer cases
to 292 non-cancer controls by clinic, age, and date of blood draw. Participants were
selected from the Alpha-Tocopherol, Beta-carotene Cancer Prevention Study (ATBC
Study) [42]. Pre-diagnosis 25-D serum levels were determined by RIA. Increasing
3
levels of 25-D were associated with a reduction in the risk of colorectal cancer. The
3
highest risk reduction was seen in the highest quartile, with more than 40% risk
reduction encountered in this group. A nested case-control study of 25-D and risk
3
of colorectal cancer was conducted within the Health Professionals Follow-up Study