a1 Department of Nutrition, Federal University of Juiz de Fora, Rua Antonio Altaf 150/201, Cascatinha 36033-330, Juiz de Fora, Minas Gerais, Brazil
a2 Department of Nutrition and Health, Federal University of Viçosa, Viçosa, MG, Brazil
a3 School of Medicine, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
Objective The present study aimed to evaluate the frequency of deficiency/insufficiency of vitamin D in adolescents and its relationship to overweight and metabolic disorders.
Design Cross-sectional study. Nutritional status was assessed by BMI according to WHO recommendations. Dietary intake was evaluated using a 3 d dietary record. The biochemical evaluation comprised measurements of serum lipids, lipoproteins, glucose, insulin, calcidiol (25(OH)D) and parathyroid hormone. Insulin resistance was calculated using the homeostasis model assessment. Body composition and blood pressure were assessed.
Setting Fifteen schools (eight public and seven private) in the central city of Juiz de Fora, Brazil.
Subjects The analysis included a study population of 160 adolescents (seventy-seven eutrophic and eighty-three overweight) aged 15 to 17 years.
Results Vitamin D deficiency and insufficiency was observed in 1·25 and 70·6 % of adolescents, respectively. Serum 25(OH)D levels were statistically lower in adolescents with weight excess, abdominal obesity, hypercholesterolaemia, higher levels of parathyroid hormone, insulin resistance, hyperinsulinaemia and hypertension (P < 0·05). Lower BMI and waist circumference were observed in the third (highest) tertile of vitamin D intake for all adolescents. The high prevalence of vitamin D insufficiency is primarily nutritional and reflects a low vitamin D intake.
Conclusions Our results support the negative association among serum 25(OH)D levels and vitamin D intake with non-skeletal outcomes in Brazilian adolescents. Vitamin D fortification of foods and/or the use of vitamin D supplements need to be considered to raise vitamin D intake in the adolescent population, even in a sunny country like Brazil.
(Received September 27 2012)
(Revised February 25 2013)
(Accepted April 01 2013)
(Online publication May 09 2013)