Indication: Cancer risk


Source: J Natl Cancer Inst, November 7, 2007;99(21):1594-602. Epub October 30, 2007.

Research: Vitamin D has been hypothesized to reduce cancer mortality through its effects on incidence and/or survival. Epidemiologic studies of the association of 25-hydroxyvitamin D [25(OH)D] and the risk of cancer, however, have been largely limited to incident cancers at a few sites. For this study, a total of 16,818 participants in the Third National Health and Nutrition Examination Survey who were 17 years or older at enrollment were followed from 1988-1994 through 2000. Levels of serum 25(OH)D were measured at baseline by radioimmunoassay. Cox proportional hazards regression models were used to examine the relationship between serum 25(OH)D levels and total cancer mortality (in the entire population or according to race/ethnicity, sex, age, and retinol status) and mortality from specific cancers. Be-cause serum was collected in the south in cooler months and the north in warmer months, researchers examined associations by collection season. All statistical tests were two-sided.

Results: Researchers identified 536 cancer deaths in 146,578 person-years. Total cancer mortality was unrelated to baseline vitamin D status in the entire population, men, women, non-Hispanic whites, non-Hispanic blacks, Mexican Americans, and in persons younger than 70 or 70 years or older. Researchers also found no interaction between vitamin D and season or vitamin D and serum retinol. Colorectal cancer mortality, however, was inversely related to se-rum 25(OH)D level, with levels 80nmol/L or higher associated with a 72% risk reduction. According to these findings, there is no association between 25(OH)D and total cancer mortality, although there was an inverse relationship between 25(OH)D levels and colorectal cancer mortality.