The efficacy of calcitriol treatment in non-alcoholic fatty liver patients with different genotypes of vitamin D receptor FokI polymorphism

BACKGROUND: Vitamin D deficiency is prevalent in patients with non-alcoholic fatty liver disease (NAFLD), but there are debates on the usefulness of vitamin D treatment. The interindividual variations in response may be due to different genetic backgrounds. The present study evaluated the efficacy of calcitriol treatment in NAFLD patients with regard to the vitamin D receptor (VDR) genotypes of FokI polymorphism. METHODS: The study was conducted on 128 NAFLD patients randomly divided into two groups and were subjected to intervention with 0.25 mcg calcitriol/day or placebo for 4 months, while anthropometric parameters, glycemic status, lipid profiles, inflammatory markers, liver enzymes, and fatty liver indices were measured. The ARMS-PCR method was used to genotype the VDR FokI polymorphism. RESULTS: Calcitriol treatments along with weight loss and diet recommendations decreased the liver enzymes (AST, ALT, and ALP, p < 0.001 for all) and fatty liver indices (HSI, p < 0.01 and APRI, p < 0.001), compared to the baseline. But when the calcitriol effects were compared to the placebo group, only ALP decrease remained significant (17.5 IU. P = 0.02). The prevalent FokI variants in our population were FF (53.1%) and Ff genotype (45.3%). No significant interaction of FokI variants to the calcitriol effects was found except for ALP. The decrease in the ALP activity was higher in calcitriol-received patients with the Ff genotype (p = 0.05). CONCLUSIONS: The FF and Ff variants of VDR FokI polymorphism did not interact with the effects of calcitriol on fatty liver, but the ALP was more responsive in subjects with the Ff variant. IRCT REGISTRATION NUMBER: IRCT2017053034222N1 Registration date: 2017-06-28 - Retrospectively registered, https://en.irct.ir/trial/26203