Compared 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 ( 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.


Citation(s):

Jenab M et al. Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations: A nested case-control study. BMJ 2010 Jan 21; 340:b5500.