Vitamin D and Colorectal Cancer

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Summary and CommentVitamin D and Colorectal CancerCompared with individuals who had the lowest blood levels of 25-hydroxyvitamin D, those who had the highest levels had lower risk for colorectal cancer.Several small studies have suggested that higher blood levels of vitamin D are associated with lower risk for colorectal cancer (CRC). To examine this association further, investigators conducted a nested, case-control study involving 520,000 participants from the general population in 10 European countries.Dietary information and blood samples were collected at study enrollment, and circulating 25-hydroxy vitamin D (25[OH]D) levels were measured. The researchers identified 1248 individuals who received diagnoses of incident CRC approximately 4 years, on average, after enrollment. These individuals were matched to 1248 healthy controls. CRC risk estimates were adjusted for potential confounding

factors, including body-mass index, smoking status, physical activity, socioeconomic status, and total energy intake, as well as consumption of fruits and vegetables, red and processed meats, and alcohol.Compared with midlevel 25(OH)D serum concentrations (50–75 nmol/L), lower 25(OH)D concentrations

(<25 and 25–50 nmol/L) were associated with higher CRC risks (incidence ratios, 1.32 and 1.28, respectively), and higher concentrations (75–100 and > 100 nmol/L) were associated with lower CRC risks (IRs, 0.88 and 0.77, respectively). Risk reductions in the higher quintiles did not reach significance compared with the middle quintile, but patients in the highest quintile had a 40% lower risk for CRC than those in the lowest quintile (P<0.001). Risk reductions were found for colon cancer but not for rectal cancer, and diminished risk for CRC was associated with greater dietary intake of calcium but not of vitamin D.Comment: This is the largest study to

address this issue, and the findings were consistent across a range of European countries. The authors are calling for prospective, randomized, controlled trials ofvitamin D supplementation, but these results seem strong enough that patients requesting advice on reducing risk for CRC can be informed that higher blood levels of 25(OH)D are associated with risk reduction.— K. Rex, MDPublished in Journal Watch

Gastroenterology February 26, 2010 Regards, Vergelpowerusa dot org