Abstract Background: the biological activity of vitamin D depends on the activity of its receptor or VDR. On the other hand, the activity of this receptor is influenced by its state of methylation. The objective of this study was to verify if the BsmI polymorphism of the VDR gene influences its methylation profile in adolescents. Secondly, it was to verify if the status of some metabolic factors (oxidative stress, inflammation, lipid profile, and glycemia) in the serum, and gender-adjusted vitamin D levels are independent factors with an influence on the VDR methylation profile. Methods and results: the study included 198 adolescents of both sexes, aged 15-19 years, who underwent testing for VDR gene methylation polymorphisms, serum vitamin D levels, and metabolic, oxidative stress, and systemic inflammation markers. It was observed that the BB genotype was less methylated than the other groups (26.1 % versus 30.3 %, and 29.3 % for Bb and bb, respectively), although without statistical differences between them. The odds ratio indicated a protection of 13 % (partially methylated) for vitamin D status, while alpha glycols increased the risk ratio (of being partially methylated) by 3 %. MDA was protective at a 28 % chance of risk that adolescents with higher levels of lipid peroxidation would be hypomethylated. Conclusion: we conclude that the methylation profile of the VDR gene is not influenced by the different BsmI polymorphism genotypes, and that serum vitamin D and serum markers of oxidative stress and inflammation can modulate this profile.

Resumen Antecedentes: la actividad biológica de la vitamina D depende de la actividad de su receptor, el VDR. Por otro lado, la actividad de este receptor está influenciada por su estado de metilación. El objetivo de este estudio es verificar si el polimorfismo BsmI del gen VDR influye en el perfil de metilación del mismo en los adolescentes. En segundo lugar, verificar si los factores metabólicos (estrés oxidativo, inflamación, perfil lipídico y glucemia) del suero y la vitamina D ajustada por sexo actúan independientemente de los polimorfismos sobre el perfil de metilación del VDR. Métodos y resultados: el estudio incluyó a 198 adolescentes de ambos sexos, de 15 a 19 años de edad, que se sometieron a análisis de polimorfismos de metilación del gen VDR, niveles de vitamina D, marcadores metabólicos, estrés oxidativo e inflamación sistémica. Se observó que el genotipo BB estaba menos metilado que los otros grupos (26,1 % contra 30,3 % y 29,3 % para Bb y bb respectivamente), aunque sin diferencias estadísticas entre ellos. El odds ratio indicó una protección del 13 % (parcialmente metilado) para el estado de la vitamina D, mientras que los alfa glicoles aumentaron el índice de riesgo (de estar parcialmente metilado) en un 3 %. La MDA fue protectora con un 28 % de probabilidad de riesgo de que los adolescentes con niveles más altos de peroxidación lipídica fueran hipometilados. Conclusión: concluimos que el perfil de metilación del gen VDR no está influenciado por los diferentes genotipos del polimorfismo BsmI y que la vitamina D y los marcadores de estrés oxidativo e inflamación en el suero pueden modular este perfil.

Abstract Objective: to verify the association of serum concentrations of 25-hydroxyvitamin D and glycemic levels with the genetic variants rs1544410 and rs2228570 of the VDR gene in adolescents from the Northeast region of Brazil. Materials and methods: a cross-sectional epidemiological study with 208 adolescents from public schools in the city of João Pessoa (Paraíba, Brazil) between 15 and 19 years of age. Blood samples were collected for DNA extraction and analysis of polymorphisms rs1544410 and rs2228570, as well as biochemical analyses (25-hydroxyvitamin D, parathyroid hormone, calcium and glycemia). Results: the mean age was 17.7 (± 1.14) years. Half of adolescents had sufficient serum levels of 25-hydroxyvitamin D and the other half had insufficient/deficient vitamin. The most frequent genotypic distribution was bb and Ff and of lesser frequency BB and ff. There was a significant relationship between the genotypes of rs1544410 and glycemia values (p = 0.049) in the relationships between the genotypes BBxbb (p = 0.012) and Bbxbb (p = 0.037); (p = 0.036, OR = 2.15, 95 % CI = 1.05-4.41), and in the BB+Bb group analysis when compared to the bb (p = 0.025, OR = 1.89, 95 % CI = 1.08-3.29) presented higher risk of glycemia above the median. On the other hand, when Bb+bb was analyzed in relation to BB, adolescents had a greater chance of blood glucose below the median (p = 0.025, OR = 0.66, CI = 0.47-0.95). Conclusion: this study showed a significant relation of glycemia with the distribution of rs1544410 polymorphism genotypes.

Resumen Objetivo: verificar la asociación de las concentraciones séricas de 25-hidroxivitamina D y los niveles de glucemia con las variantes genéticas rs1544410 y rs2228570 del gen VDR en adolescentes de la región noreste de Brasil. Materiales y métodos: se realizó un estudio epidemiológico transversal con 208 adolescentes de escuelas públicas en la ciudad de João Pessoa (Paraíba, Brasil) de entre 15 y 19 años de edad. Se recogieron muestras de sangre para la extracción de ADN y el análisis de los polimorfismos rs1544410 y rs2228570, así como para análisis bioquímicos (25-hidroxivitamina D, hormona paratiroidea, calcio y glucemia). Resultados: la edad media fue de 17,7 (± 1,14) años. La mitad de los adolescentes tenía niveles séricos suficientes de 25-hidroxivitamina D y la otra mitad, vitamina insuficiente/deficiente. La distribución genotípica más frecuente fue bb y Ff y la de menor frecuencia, BB y ff. Hubo una relación significativa entre los genotipos de rs1544410 y los valores de glucemia (p = 0,049) en las relaciones entre los genotipos BBxbb (p = 0,012) y Bbxbb (p = 0,037); (p = 0,036, OR = 2,15, IC 95 % = 1,05-4.41), y el análisis del grupo BB + Bb en comparación con el bb (p = 0,025, OR = 1,89, IC 95 % = 1,08-3,29) mostró un mayor el riesgo de glucemia, por encima de la mediana. Por otro lado, cuando se analizó Bb+bb en relación con la BB, los adolescentes tuvieron una mayor probabilidad de que la glucosa en sangre estuviera por debajo de la mediana (p = 0,025, OR = 0,66, IC = 0,47-0,95). Conclusión: este estudio mostró una relación significativa entre la glucemia y la distribución de genotipos de polimorfismo rs1544410.

OBJETIVO: Avaliar fatores relacionados à prevalência da hipovitaminose D e relação com pressão arterial em 91 idosos hipertensos de João Pessoa, PB/BR. MATERIAIS E MÉTODOS: Em estudo transversal, níveis de 25-hidroxivitamina D foram comparados com dados bioquímicos, antropométricos, dietéticos, tipo de pele, exposição solar e pressão arterial. RESULTADOS: A prevalência da inadequação da vitamina (25-hidroxivitamina D < 29 ng/mL) foi 33%. A concentração sérica de 25-hidroxivitamina D associou-se inversamente com a pressão arterial sistólica e positivamente com frequência semanal do consumo de peixes. As outras variáveis estudadas não mostraram associação significativa com 25-hidroxivitamina D. CONCLUSÃO: A prevalência da inadequação das concentrações de vitamina D foi elevada e relacionada com maior pressão arterial em idosos. Por outro lado, um maior consumo semanal de peixe está ligado a maiores concentrações da 25-hidroxivitamina D.

OBJECTIVE: To evaluate the prevalence of inadequate vitamin D status and its relationship with associated factors in 91 elderly hypertensive patients in João Pessoa, PB/BR. MATERIALS AND METHODS: In a cross-sectional study, levels of 25-hydroxyvitamin D of 91 elderly patients were compared with biochemical, anthropometric, and dietary data, type of skin, exposure to sunlight, and blood pressure. RESULTS: The prevalence of inadequate vitamin concentrations (25-hydroxyvitamin D < 29 ng/mL) was 33%. The concentration of serum 25-hydroxyvitamin D was inversely associated with systolic blood pressure and positively associated with weekly fish consumption. The other variables showed no significant association with 25-hydroxyvitamin D. CONCLUSION: The prevalence of inadequate vitamin D concentrations was related with higher blood pressure in elderly patients. Moreover, greater fish weekly consumption influenced greater 25-hydroxyvitamin D concentration.