Status de vitamina D e fatores de risco cardiometabólico em adolescentes com sobrepeso/obesidade

Abstract

The prevalence of obesity and cardiometabolic changes in the child and adolescent population has increased considerably worldwide, and has been associated with hypovitaminosis D, but few studies have been conducted in sunny regions in northeastern Brazil. Thus, the objective of the present study was to evaluate the association between vitamin D status with associated factors and cardiometabolic risk in overweight / obesity adolescents. This is a cross-sectional study carried out by non-probabilistic sampling, with all adolescents between 10 and 19 years of age, both boys and girls attending the pediatric outpatient clinic of the University Hospital Onofre Lopes / UFRN, Natal/RN, in the period of September 2016 and November 2018, diagnosed with overweight or obesity. Clinical, biochemical, anthropometric data, skin phototype, sun exposure and physical activity were evaluated. 25- hydroxyvitamin D (25OHD) was analyzed by the chemiluminescence method. The adolescents were grouped according to the concentrations of 25OHD in "sufficient" (> 30ng / mL) and "hypovitaminosis D" (≤30ng / mL). Comparisons of the variables between the groups were performed using appropriate statistical tests. Correlations between 25OHD concentrations and continuous variables were evaluated by the Spearman coefficient (r). The relationship between the independent variables and the 25OHD concentration was adjusted accordingly using the generalized linear regression model. The sample consisted of 125 adolescents, most males in the age range of 10 to 11 years. A frequency of 45.6% of hypovitaminosis D and a mean concentration of 25 (OH) D of 32.73 ng / mL were found in the general population independent of sex. There was a higher percentage of hypovitaminosis D (56.1%) in the female sex. There were statistically significant associations between hypovitaminosis D and age (X² = 7.45, p = 0.024), blood pressure (X² = 7.56, p = 0.006), neck circumference (X² = 5.84, p = 0.016), HOMA-IR index (X² = 5.84, p = 0.016), blood pressure (X² = 7.56, p = 0.006). After adjusting for sexual maturation, serum concentrations of 25 (OH) D showed a significant positive correlation with sun exposure (r = 0.321, p = 0.000), physical activity (r = 0.189, p = 0.034); and significant negative correlation with blood pressure (r = -0.288, p = 0.001), body weight (r = -0.236, p = 0.008), neck circumference (r = -0.200, p = 0.025), PTH 0.229, p = 0.020), fasting insulin (r = -0.375, p = 0.000) and HOMA-IR (r = -0.386, p = 0.000). In the analysis of the generalized linear regression model, a significant positive association between vitamin D status and weekly sun exposure was identified (OR = 0.96, 95% CI 0.92 - 0.99, p <0.05). There were significant negative associations between vitamin D status and blood pressure classified according to the percentile (OR = 4.00, 95% CI 1.19 to 13.37, p <0.05), body weight (OR = 1.04, 95% CI 1.01 - 1.07, p <0.05), fasting insulin (OR = 1.13; 95% CI 1.05 - 1.22, p <0.05), and blood pressure as the diagnostic criterion for metabolic syndrome (OR = 4.73, 95% CI 1.45-15.45, P <0.05). It was concluded that low sun exposure influences hypovitaminosis D and that the decrease of 25 (OH) D favors the elevation of blood pressure, excess weight and insulin resistance in overweight / obesity adolescents from a sunny region.