Table 2.
Study-specific and summary associations of vitamin D–binding protein isoforms with vitamin D nonsufficiency* in the EPIC, CPS-II, and NHS cohorts
| Study DBP isoform (rs4588 genotype) | <50 nmol/L (nonsufficient) | ≥50 nmol/L (sufficient) | <50 vs. ≥50 nmol/LOR (95% CI)† | P trend |
|---|---|---|---|---|
| EPIC | ||||
| DBP1-1 (CC) | 674 | 254 | 1.00 (Referent) | |
| DBP1-2 (CA) | 560 | 173 | 1.41 (1.11 to 1.78) | |
| DBP2-2 (AA) | 138 | 26 | 2.59 (1.63 to 4.42) | |
| Per DBP2 isoform (per A allele) | 1372 | 453 | 1.52 (1.26 to 1.82) | 8.7 × 10−6 |
| CPS-II | ||||
| DBP1-1 (CC) | 78 | 180 | 1.00 (Referent) | |
| DBP1-2 (CA) | 53 | 120 | 1.03 (0.67 to 1.57) | |
| DBP2-2 (AA) | 12 | 20 | 1.47 (0.68 to 3.18) | |
| Per DBP2 isoform (per A allele) | 143 | 320 | 1.13 (0.82 to 1.55) | .42 |
| NHS | ||||
| DBP1-1 (CC) | 149 | 421 | 1.00 (Referent) | |
| DBP1-2 (CA) | 120 | 282 | 1.20 (0.91 to 1.60) | |
| DBP2-2 (AA) | 47 | 52 | 2.55 (1.65 to 3.95) | |
| Per DBP2 isoform (per A allele) | 316 | 755 | 1.46 (1.20 to 1.77) | .0002 |
| All studies‡ | ||||
| DBP1-1 (CC) | 901 | 855 | 1.00 (Referent) | |
| DBP1-2 (CA) | 733 | 575 | 1.27 (1.08 to 1.50) | |
| DBP2-2 (AA) | 197 | 98 | 2.36 (1.74 to 3.19) | |
| Per DBP2 isoform (per A allele) | 912 | 2447 | 1.43 (1.27 to 1.62) | 1.2 × 10−8 |
25(OH)D = 25-hydroxyvitamin D; CI = confidence interval; CPS-II = Cancer Prevention Study-II; DBP = vitamin D–binding protein; EPIC = European Prospective Investigation into Cancer and Nutrition; NHS = Nurses’ Health Study; OR = odds ratio.
According to 2011 Institute of Medicine recommendations based on circulating 25(OH)D concentrations; 25(OH)D blood concentrations were calibrated to the same assay and seasonally adjusted using the method described by Gail et al. (21).
Odds ratio and 95% confidence interval estimated in logistic regression models adjusted for age (continuous), sex, study center (for EPIC models), and case-control status.
Odds ratios and 95% confidence intervals estimated in fixed-effects meta-analyses (I2 = 0.0 to 22.1; Pheterogeneity by study > .25 for all summary estimates).