Table 3.
Association of Vitamin D3 Supplementation With Risk of Advanced Adenoma Stratified by 2 VDR Genotypes
| SNP | VDR Genotype | Participants, No. (%) | No. With Advanced Adenoma/Total No. (%) | RR (95% CI)a | P Valuea | P Valueb | |
|---|---|---|---|---|---|---|---|
| No Vitamin D | Vitamin D | ||||||
| rs7968585 (n = 1687) | AA | 436 (25.8) | 32/222 (14.4) | 11/214 (5.1) | 0.36 (0.19–0.69) | .002 | .001 |
| AG | 837 (49.6) | 31/422 (7.4) | 43/415 (10.4) | 1.41 (0.90–2.19) | .13 | ||
| GG | 414 (24.5) | 17/198 (8.6) | 27/216 (12.5) | 1.42 (0.79–2.53) | .24 | ||
| AG or GGc | 1251 (74.1) | 48/620 (7.7) | 70/631 (11.1) | 1.41 (0.99–2.00) | .05 | <.001 | |
| rs731236 (Taq1) (n = 1671) | TT | 631 (37.8) | 24/306 (7.8) | 38/325 (11.7) | 1.44 (0.89–2.35) | .14 | .001 |
| CT | 788 (47.2) | 37/402 (9.2) | 36/386 (9.3) | 1.02 (0.66–1.58) | .94 | ||
| CC | 252 (15.1) | 19/126 (15.1) | 4/126 (3.2) | 0.22 (0.07–0.63) | .005 | ||
Abbreviations: RR, relative risk; SNP, single-nucleotide polymorphism.
Relative risk for the effect of vitamin D3 supplementation on advanced adenomas and Wald test P values adjusted for age, sex, and calcium treatment assignment; threshold for significance is P < .05.
Wald test P value for interaction between SNP genotype and vitamin D3 supplementation on risk of advanced adenoma. Accounting for multiple testing, threshold for significance is P < .002. Note: a significant interaction test result indicates that there is evidence for heterogeneity between the effects of vitamin D treatment on risk of advanced adenoma outcomes in the different genotype subgroups. The individual estimates and their 95%CIs show how they differ. A significant test of interaction result does not imply that the estimates in each subgroup are necessarily statistically significant.
Post hoc analysis of dominant genetic model.