Influência de variantes genéticas na concentração de vitamina D de pacientes com síndrome metabólica e a associação entre a 25(OH)D com os componentes da síndrome e fatores associados

Abstract

Introduction: hydroxyvitamin D [25(OH)D] corresponds to the main circulating metabolite of vitamin D and is the best biomarker to indicate the concentration of this vitamin in the body. In this sense, skin exposure to sunlight and ingestion of food sources of this vitamin are factors that can affect the concentration of circulating 25(OH)D. However, multiple genetic studies on key genes in the vitamin D metabolic pathway have shown a strong influence of genetic variants on 25(OH)D concentration. Objectives: to investigate whether genetic variants in the DHCR7 (rs12785878), GC/BPD (rs7041), CYP27B1 (rs4646536), CYP2R1 (rs10741657) and VDR (rs1544410) genes influence the concentration of vitamin D [25(OH)D] in patients with metabolic syndrome (MS) and to assess whether there is an association between the concentration of vitamin D with the components of MS and factors associated with the syndrome. Material and Methods: observational, analytical, cross-sectional study, consisting of 338 volunteer participants with Metabolic Syndrome diagnosed with the parameters of the International Diabetes Federation (2006). The recommendations of the I Brazilian Guidelines on Metabolic Syndrome (2005) were used to identify the factors associated with the syndrome. The 25-hydroxyvitamin D [25(OH)D] was used as a biomarker. DNA extraction performed (Miller, Dykes and Polesky salt extraction method); quantification [using NanoDropTM One®] and polymorphism genotyping (using TaqMan® quantitative real-time PCR technology. Results: statistical significance was observed between the increase in body mass index (BMI) and the low concentration of vitamin D (p=0.030). A trend towards statistical significance was found between the GC/BDP gene rs7041 with diastolic blood pressure (DBP) (p=0.077) and between the VDR gene, variant rs1544410, with systolic blood pressure (SBP) (0.081). Among the components of the syndrome, statistical significance was observed between low concentrations of vitamin D with increased diastolic blood pressure (p=0.009) and high triglycerides (p=0.040); with associated factors: altered Homa-IR index (p=0.018); LDL-c (p=0.043) and Total Cholesterol (p=0.028), both high. There was no statistical significance between the quantity of components of the syndrome and the concentration of vitamin D. Conclusion: A trend towards statistical significance was found between the GC/BDP gene rs7041 with diastolic blood pressure (DBP) (p=0.077) and between the VDR gene, variant rs1544410, with blood pressure systolic blood pressure (SBP) (0.081). There was no significant association between the evaluated SNPs and vitamin D concentration, as well as with the components of the metabolic syndrome. We found a significant association between serum vitamin D concentration and diastolic blood pressure, triglycerides, HOMA-IR, total cholesterol, LDL-c and body mass index. There was no statistical significance between the quantity of components of the syndrome and the concentration of vitamin D, and that in these patients with hypovitaminosis D, the cardiometabolic risk seems to be even greater.