Table 4.

Risk of colorectal cancer according to vitamin D-related biomarkers in the Nurses' Health Study (1990–2011)

BiomarkerQuintile 1Quintile 2Quintile 3Quintile 4Quintile 5Per 1-standard deviation incrementaP for trend
Total 25(OH)D
 Median, nmol/Lb38.055.868.779.8101.5
 No. of cases/controls (n = 378/689)94/13887/13869/13876/13852/137
 Age-adjusted OR (95% CI)c1 (referent)0.85 (0.58–1.25)0.68 (0.46–1.02)0.73 (0.49–1.09)0.51 (0.33–0.79)0.76 (0.64–0.91)0.002
 Multivariable-adjusted OR (95% CI)d1 (referent)0.88 (0.59–1.32)0.76 (0.50–1.16)0.77 (0.50–1.18)0.54 (0.33–0.87)0.78 (0.65–0.95)0.01
VDBP
 Median, nmol/Lb2,5283,9944,8155,9047,749
 No. of cases/controls (n = 378/689)83/13782/13870/13964/13879/137
 Age-adjusted OR (95% CI)c1 (referent)1.01 (0.68–1.51)0.87 (0.57–1.30)0.80 (0.54–1.20)0.96 (0.65–1.43)0.96 (0.84–1.11)0.59
 Multivariable-adjusted OR (95% CI)d1 (referent)1.01 (0.67–1.53)0.88 (0.58–1.34)0.82 (0.54–1.24)0.98 (0.65–1.47)0.97 (0.84–1.12)0.68
Free 25(OH)D
 Median, pmol/Lb10.816.320.826.339.6
 No. of cases/controls (n = 378/689)94/13895/13742/13882/13965/137
 Age-adjusted OR (95% CI)c1 (referent)0.97 (0.66–1.42)0.43 (0.28–0.67)0.81 (0.55–1.19)0.65 (0.43–0.99)0.85 (0.73–1.00)0.05
 Multivariable-adjusted OR (95% CI)d1 (referent)1.01 (0.68–1.49)0.45 (0.28–0.71)0.83 (0.55–1.25)0.71 (0.46–1.10)0.88 (0.74–1.04)0.13
Bioavailable 25(OH)D
 Median, nmol/Lb4.16.38.010.415.4
 No. of cases/controls (n = 378/689)88/13784/13949/13775/13982/137
 Age-adjusted OR (95% CI)c1 (referent)0.90 (0.61–1.34)0.53 (0.35–0.82)0.82 (0.55–1.21)0.84 (0.56–1.26)0.97 (0.83–1.13)0.71
 Multivariable-adjusted OR (95% CI)d1 (referent)0.92 (0.61–1.39)0.54 (0.34–0.84)0.84 (0.55–1.29)0.92 (0.60–1.42)1.01 (0.86–1.19)0.92
VDBP-bound 25(OH)D
 Median, nmol/Lb33.148.059.070.490.4
 No. of cases/controls (n = 378/689)96/13890/13860/13783/13849/138
 Age-adjusted OR (95% CI)c1 (referent)0.89 (0.61–1.31)0.58 (0.38–0.87)0.82 (0.55–1.21)0.45 (0.29–0.71)0.75 (0.63–0.89)0.001
 Multivariable-adjusted OR (95% CI)d1 (referent)0.93 (0.62–1.38)0.63 (0.41–0.97)0.86 (0.57–1.32)0.48 (0.29–0.78)0.77 (0.63–0.93)0.006
  • aThe standard deviation among controls was 26.5 nmol/L for total 25(OH)D, 1,955 nmol/L for VDBP, 12.0 pmol/L for free 25(OH)D, 4.7 nmol/L for bioavailable 25(OH)D, and 24.0 nmol/L for VDBP-bound 25(OH)D.

  • bMedian was calculated among control participants.

  • cAdjusted for matching factors (age and time of blood draw).

  • dAdditionally adjusted for family history of colorectal cancer, multivitamin use, pack-years of smoking (0, 0–9.9, 10–24.9, 25–49.9, ≥50), alcohol consumption (0, 0–5.0, 5.1–15.0, >15 g/d), BMI (continuous), physical activity (≤5, 5.1–10, 10.1–20, >20 METs), regular aspirin/NSAID use, postmenopausal status and hormone use (premenopausal, never use of postmenopausal hormone, ever use of postmenopausal hormone), calcium intake (in quartiles), and Alternative Healthy Eating Index (in quartiles).