Table 2.

Associations between vitamin D biomarkers and colorectal cancer risk, African American participants of the SCCS

BiomarkerControlsCasesORa (95% CI)PtrendORb (95% CI)Ptrend
25(OH)D, ng/mL
 Tertile 1: ≤10.49102711 (Ref)1 (Ref)
 Tertile 2: 10.50–16.08103470.65 (0.41–1.04)0.62 (0.38–1.01)
 Tertile 3: >16.08107570.77 (0.48–1.21)0.73 (0.45–1.17)
 Per standard deviation increase0.87 (0.71–1.06)0.170.82 (0.66–1.02)0.07
VDBP, μg/mL
 Tertile 1: ≤280.20146741 (Ref)1 (Ref)
 Tertile 2: 280.21–320.00145690.93 (0.62–1.40)0.95 (0.63–1.45)
 Tertile 3: >320.00149811.10 (0.74–1.64)1.08 (0.72–1.63)
 Per standard deviation increase1.04 (0.88–1.23)0.661.03 (0.87–1.23)0.70
Free 25(OH)Dc
 Tertile 1: ≤5.02103601 (Ref)1 (Ref)
 Tertile 2: 5.03–7.77102570.92 (0.57–1.46)0.85 (0.53–1.39)
 Tertile 3: >7.77107580.90 (0.56–1.44)0.83 (0.51–1.36)
 Per standard deviation increase0.87 (0.71–1.06)0.160.82 (0.66–1.01)0.07
  • Abbreviations: 25(OH)D, 25-hydroxyvitamin D; VDBP, vitamin D–binding protein; Ref, reference.

  • aAnalyses result from conditional logistic regression models where cases and controls are matched on age, race, and sex. Analyses are adjusted for calendar week of sample collection, and body mass index.

  • bIn addition, adjusted for education, smoking, physical activity, alcohol intake, history of colorectal cancer screening, and family history of colorectal cancer.

  • cFree 25(OH)D biomarker is calculated as 25(OH)D:VDBP molar ratio (×103) and is a proxy for free 25-hydroxyvitamin D status.