Optimal Vitamin D Status for Colorectal Cancer Prevention. A Quantitative Meta Analysis

Section of Endocrinology, Diabetes, Nutrition, Boston University, Boston, Massachusetts, United States
American Journal of Preventive Medicine (Impact Factor: 4.53). 04/2007; 32(3):210-6. DOI: 10.1016/j.amepre.2006.11.004
Source: PubMed


Previous studies, such as the Women's Health Initiative, have shown that a low dose of vitamin D did not protect against colorectal cancer, yet a meta-analysis indicates that a higher dose may reduce its incidence.
Five studies of serum 25(OH)D in association with colorectal cancer risk were identified using PubMed. The results of all five serum studies were combined using standard methods for pooled analysis. The pooled results were divided into quintiles with median 25(OH)D values of 6, 16, 22, 27, and 37 ng/mL. Odds ratios were calculated by quintile of the pooled data using Peto's Assumption-Free Method, with the lowest quintile of 25(OH)D as the reference group. A dose-response curve was plotted based on the odds for each quintile of the pooled data. Data were abstracted and analyzed in 2006.
Odds ratios for the combined serum 25(OH)D studies, from lowest to highest quintile, were 1.00, 0.82, 0.66, 0.59, and 0.46 (p(trend)<0.0001) for colorectal cancer. According to the DerSimonian-Laird test for homogeneity of pooled data, the studies were homogeneous (chi(2)=1.09, df=4, p=0.90. The pooled odds ratio for the highest quintile versus the lowest was 0.49 (p<0.0001, 95% confidence interval, 0.35-0.68). A 50% lower risk of colorectal cancer was associated with a serum 25(OH)D level > or =33 ng/mL, compared to < or =12 ng/mL.
The evidence to date suggests that daily intake of 1000-2000 IU/day of vitamin D(3) could reduce the incidence of colorectal with minimal risk.

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    • "A preliminary analysis of the WHI RCT does not indicate that vitamin D supplements reduce the risk of CRC after a seven-year follow-up period.51 A re-evaluation of these data consistently shows an interaction with estrogens, to the extent that vitamin D amends the effect in relation to the CRC risk depending on whether estrogens were administered concomitantly or not.52 "
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    • "cit.) and adenoma recurrence [16–18]. Lower dietary intakes of vitamin D have been associated with a higher risk of developing colonic neoplasia [12, 19–21]. Some have suggested that vitamin D insufficiency, which increases with advancing age, is a factor contributing to sporadic CRC, which is also associated with aging [22]. "
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    • "In 1980, Garland and Garland hypothesized that lower concentrations of vitamin D, resulting from much weaker UV-B radiation at higher latitudes, may account for the striking geographical pattern of cancer mortality (Garland and Garland, 1980). This hypothesis has remained subject to ongoing debate and further investigation (Armstrong, 2006; Boscoe and Schymura, 2006; Giovannucci, 2006; Gorham et al., 2007; Kampman et al., 2000). "
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