Abstract Background: obesity can influence vitamin D levels, which in turn might be associated with cardiometabolic risk factors. Objectives: this study assessed the association between 25-hydroxyvitamin D [25(OH)D] levels and cardiometabolic risk factors in adolescents with overweight living in a region of northeastern Brazil. Material and methods: a cross-sectional study was carried out by non-probabilistic sampling in adolescents diagnosed with overweight or obesity. The subjects were divided according to their 25(OH) D status into two groups: sufficient vitamin D and hypovitaminosis D. Biodemographic, lifestyle, cardiometabolic, and biochemical factors were evaluated. A logistic regression model was applied to determine the predictors of hypovitaminosis D. Results: we found a high frequency of hypovitaminosis D (45.6 %) in adolescents. Weekly sun exposure was negatively associated with hypovitaminosis D (OR = 0.96; 95 % CI: 0.92-0.99), while significant positive associations were observed between hypovitaminosis D and blood pressure above the 95th percentile (OR = 4.00; 95 % CI: 1.19-13.37), body weight (OR = 1.04; 95 % CI: 1.01-1.07), and fasting insulin (OR = 1.13; 95 % CI: 1.05-1.22). Conclusion: hypovitaminosis D showed a high prevalence in adolescents with overweight living in a sunny region of northeastern Brazil, and cardiometabolic risk factors such as systemic arterial hypertension, high body weight, and hyperinsulinemia are predictors of hypovitaminosis D.

Resumen Introducción: la obesidad puede influir en los niveles de vitamina D, lo que a su vez podría estar asociado con factores de riesgo cardiometabólico. Objetivos: este estudio evaluó la asociación entre los niveles de 25-hidroxivitamina D [25(OH)D] y los factores de riesgo cardiometabólico en adolescentes con sobrepeso que viven en una región del noreste de Brasil. Material y métodos: se realizó un estudio transversal mediante muestreo no probabilístico con adolescentes diagnosticados de sobrepeso u obesidad. Los sujetos se dividieron según su estado de 25(OH) D en dos grupos: suficiente vitamina D e hipovitaminosis D. Se evaluaron factores biodemográficos, de estilo de vida, cardiometabólicos y bioquímicos. Se aplicó un modelo de regresión logística para determinar los predictores de la hipovitaminosis D. Resultados: encontramos una alta frecuencia de hipovitaminosis D (45,6 %) en los adolescentes. La exposición semanal al sol se asoció negativamente a la hipovitaminosis D (OR = 0,96; IC 95 %: 0,92-0,99), mientras que se observaron asociaciones positivas significativas entre hipovitaminosis D y presión arterial por encima del percentil 95 (OR = 4,00; IC 95 %: 1,19-13,37), peso corporal (OR = 1,04; IC del 95 %: 1,01-1,07) e insulina en ayunas (OR = 1,13; IC del 95 %: 1,05-1,22). Conclusión: la hipovitaminosis D mostró una alta prevalencia entre los adolescentes con sobrepeso que viven en una región soleada del noreste de Brasil, y los factores de riesgo cardiometabólico, como hipertensión arterial sistémica, peso corporal elevado e hiperinsulinemia, son predictores de hipovitaminosis D.

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.

RESUMO Objetivo: Investigar a associação do perfil hematológico com os níveis séricos de 25-hidroxivitamina D e polimorfismo BsmI do gene vitamina D receptor de idosos não institucionalizados. Métodos: Estudo transversal realizado com 142 idosos de ambos os sexos. Foram coletadas, por meio de um questionário, informações sociodemográficas, antecedentes clínicos e fatores associados à exposição solar. Além disso, foram aferidas medidas antropométricas de peso, altura e circunferência da cintura. Material biológico foi coletado para análise dos parâmetros bioquímicos (25-hidroxivitamina D, parathormone, cálcio sérico, ureia, creatinina, enzimas hepáticas e perfil hematológico) e para identificação do polimorfismo BsmI do gene vitamina D receptor. Resultados: Os participantes do estudo eram, em sua maioria, do sexo feminino (80,3%) e apresentaram concentrações médias de 25-hidroxivitamina D, hemoglobina e hematócrito de 32,1±7,3 ng/dL, 13,5±1,5 d/dL e 40,0±4,4%, respectivamente. Da amostra total, 40,8% (n=58) apresentaram insuficiência/deficiência de vitamina D (25,7±3,3 ng/mL) e 12,6% (n=18), anemia. Encontrou-se associação entre as concentrações séricas de vitamina D com as de hemoglobina (p=0,030) e hematócrito (p=0,032). Entretanto, quando os sujeitos foram categorizados quanto à presença ou não de anemia, essa associação não se manteve (p=0,270). Além disso, não foi observada relação entre o polimorfismo BsmI e as concentrações de hemoglobina e hematócrito nos grupos de idosos com suficiência ou insuficiência/deficiência de vitamina D. Conclusão: O presente estudo encontrou associação entre as concentrações séricas de vitamina D e as de hematócrito e hemoglobina nos idosos analisados. Contudo, não foram observadas associações entre esses parâmetros hematológicos e o polimorfismo BsmI do gene vitamina D receptor.

ABSTRACT Objective: To investigate the association between serum level of 25-hydroxy vitamin D and the Vitamin D Receptos gene BsmI polymorphism in the blood profile of community-dwelling older adults. Methods: This cross-sectional study included 142 older males and females. A questionnaire collected socio demographic information, medical history, and factors associated with sun exposure. Weight, height, and waist circumference were measured. Biological material was collected to analyze biochemical parameters 25-hydroxy vitamin D, parathormone, serum calcium, urea, creatinine, liver enzymes, and blood profile) and to verify the presence of the vitamin D receptos gene BsmI polymorphism. Results: Most participants were female (80.3%). The mean levels of 25-hydroxy vitamin D, hemoglobin, and hematocrit were 32.1±7.3 ng/dL, 13.5±1.5 d/dL, and 40.0±4.4%, respectively. Fifty-eight (40.8%) participants had vitamin D insufficiency/deficiency (25.7±3.3 ng/mL), and 18 (12.6%) had anemia. Serum vitamin D was associated with hemoglobin (p=0.030) and hematocrit (p=0.032). However, when subjects were categorized as anemic or not anemic, said association was not maintained (p=0.270). Moreover, the BsmI polymorphism was not associated with hemoglobin and hematocrit levels, regardless of vitamin D status. Conclusion: The serum level of vitamin D is associated with hematocrit and hemoglobin levels in older adults. However, these blood parameters were not associated with the vitamin D receptor gene BsmI polymorphism.