Avaliação dos níveis séricos da vitamina D, e sua correlação com fatores de risco para hipovitaminose em adolescentes

Abstract

The insufficiency and deficiency of vitamin D has been considered a public health problem worldwide, in reason of its implications in the development of several diseases, among them diabetes mellitus type 2, obesity, arterial hypertension, osteoporosis, osteomalacia. In the pediatric population, vitamin D is important in development and bone mineralization. In these individuals, the bone tissue reaches its maximum amount, so vitamin D is considered a predominant factor for fracture risk in senescence. The objective of this study was to evaluate the intake and serum levels of vitamin D in healthy female adolescent of the age of 15-18 years, as well as the factors that may influence the concentration of vitamin D: adiposity, sun exposure, applying sunscreen, physical activity. Furthermore, we evaluated the correlation of serum vitamin D and vitamin D intake with biochemical data, blood pressure, and the important factors for the maintenance of adequate levels of vitamin D. The sample consisted of 69 students with an average age of 16.35. We evaluated biochemical dosages (25-hydroxy-vitamin D, parathyroid hormone, serum glucose, total calcium, alkaline phosphatase, glutamicoxaloacetic transaminase, glutamic pyruvic transaminase, creatinine, phosphorus), food intake (three-day dietary records), conducting activity physical (questionnaire stipulated by Florindo et al), analyzes anthropometric (weight, height, BMI, body fat), blood pressure measurement. It was found that 63.8% of adolescents had hypovitaminosis D. Only 7.24% of girls ingest adequate amounts of vitamin D. We observed an inverse relationship between PTH and serum levels of vitamin D. We found no correlation between serum levels of vitamin D with anthropometric measurements, use of sunscreen, sun exposure, physical activity, and intake of nutrients (vitamin D, calcium, phosphorus). There was an inverse relationship between vitamin D intake and serum calcium levels. We also found an inverse correlation between the intake of calcium and PTH. The study demonstrated a high incidence of hypovitaminosis D in female adolescents and most of the teenagers do not ingest adequate amounts of vitamin D. The low serum levels of vitamin D can lead to increased PTH and may in the future cause a secondary hyperparathyroidism. Adequate intake of vitamin D provides a satisfactory absorption of calcium and consequently a proper bone mineralization. Furthermore, the study showed that a satisfactory intake of calcium is important to maintain parathyroid function.