Serum 25-Hydroxyvitamin D and Cancer Mortality in the NHANES III Study (1988―2006)

Vitamin D has been hypothesized to protect against cancer. We followed 16,819 participants in NHANES III (Third National Health and Nutritional Examination Survey) from 1988 to 2006, expanding on an earlier NHANES III study (1988-2000). Using Cox proportional hazards regression models, we examined risk related to baseline serum 25-hydroxyvitamin D [25(OH)D] for total cancer mortality, in both sexes, and by racial/ethnic groups, as well as for site-specific cancers. Because serum was collected in the south in cooler months and in the north in warmer months, we examined associations by collection season ("summer/higher latitude" and "winter/lower latitude"). We identified 884 cancer deaths during 225,212 person-years. Overall cancer mortality risks were unrelated to baseline 25(OH)D status in both season/latitude groups, and in non-Hispanic whites, non-Hispanic blacks, and Mexican-Americans. In men, risks were elevated at higher levels {e.g., for ≥100 nmol/L, relative risk (RR) = 1.85 [95% confidence interval (CI), 1.02-3.35] compared with