Total and Free Circulating Vitamin D and Vitamin D-Binding Protein in Relation to Colorectal Cancer Risk in a Prospective Study of African Americans

Cancer Epidemiol Biomarkers Prev. 2017 Aug;26(8):1242-1247. doi: 10.1158/1055-9965.EPI-17-0133. Epub 2017 May 8.

Abstract

Background: Previous studies rarely evaluated the associations between vitamin D-binding protein and free vitamin D with colorectal cancer risk. We assessed these biomarkers and total 25-hydroxyvitamin D in relation to colorectal cancer risk in a sample of African Americans.Methods: Cases comprised 224 African American participants of the Southern Community Cohort Study diagnosed with incident colorectal cancer. Controls (N = 440) were selected through incidence density sampling and matched to cases on age, sex, and race. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for associations between biomarker levels and colorectal cancer risk.Results: Vitamin D was inversely associated with colorectal cancer risk where the OR per-SD increase in total and free 25-hydroxyvitamin D were 0.82 (95% CI, 0.66-1.02) and 0.82 (95% CI, 0.66-1.01), respectively. Associations were most apparent among cases diagnosed >3 years after blood draw: ORs for the highest tertile versus the lowest were 0.69 (95% CI, 0.21-0.93) for total 25-hydroxyvitamin D and 0.71 (95% CI, 0.53-0.97) for free 25-hydroxyvitamin D. Inverse associations were seen in strata defined by sex, BMI, and anatomic site, although not all findings were statistically significant. Vitamin D-binding protein was not associated with colorectal cancer risk.Conclusions: Our findings suggest that total and free 25-hydroxyvitamin D may be inversely associated with colorectal cancer risk among African Americans.Impact: These findings highlight a potential role for vitamin D in colorectal cancer prevention in African Americans. Cancer Epidemiol Biomarkers Prev; 26(8); 1242-7. ©2017 AACR.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • African Americans
  • Colorectal Neoplasms / epidemiology
  • Colorectal Neoplasms / prevention & control*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies
  • Risk Factors
  • Vitamin D / blood
  • Vitamin D / therapeutic use*
  • Vitamin D-Binding Protein / blood
  • Vitamin D-Binding Protein / therapeutic use*

Substances

  • Vitamin D-Binding Protein
  • Vitamin D