Common genetic variants of the vitamin D binding protein (DBP) predict differences in response of serum 25-hydroxyvitamin D [25(OH)D] to vitamin D supplementation

BackgroundTo determine the effect of vitamin D binding protein (DBP) genotypes on 25-hydroxyvitamin D [25(OH)D] changes with vitamin D supplements, we studied 98 adults receiving 600 or 4000 IU/d vitamin D3 for one year.MethodsThe DBP functional variant, T436K, was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).ResultsMean 25(OH)D increases were 97% for TT (n = 48), 151% for TK (n = 31) and 307% (n = 6) for KK genotypes (p = .004).ConclusionsAs with baseline 25(OH)D, T436K genotype predicts 25(OH)D changes after long-term vitamin D supplementation.