Association of vitamin D insufficiency with adiposity and metabolic disorders in Brazilian adolescents

Abstract

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 (seventyseven 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.

Prevalence of Hypovitaminosis D and Associated Factors in Adolescent Students of a Capital of Northeastern Brazil

“…The sociodemographic variables included age, gender and skin color (self-reported) (14), if receiving social government benefits and maternal education (as indirect indicators of socioeconomic status of participants). Behavioral variables covered hours of sleep per day, daily sun exposure being higher or lower than 30 minutes (7,15), practice of physical activity while being exposed to the sun, performing physical activity or inactivity and habitual dietary intake of vitamin D.…”

“…Only three studies in Brazil working specifically with adolescents were identified, showing a prevalence above 60% for hypovitaminosis D in adolescents in the south and southeast regions of the country (7)(8)(9).…”

Association of vitamin D with adiposity measures and other determinants in a cross-sectional study of Cypriot adolescents

“…Furthermore, we looked at this association across the whole spectrum of adiposity. Previous studies have generally either looked at this association among the obese only (11,13,31) , while studies that have expanded their investigation beyond the high end of the spectrum have included underweight individuals within the BMI , 25?0 kg/m 2 category or assumed that the relationship is linear (3)(4)(5)(6)30,38) . The present study has specifically looked at vitamin D status at the lower end of the BMI/BF% spectrum and has provided evidence that people within the lower end of adiposity might also have compromised vitamin D levels.…”

Consumo alimentar e síndrome metabólica em adolescentes

“…Oliveira et al [41], avaliando adolescentes brasileiros de 15 a 17 anos, encontraram menor ingestão de vitamina D entre os indivíduos com excesso de peso quando comparados com os eutróficos. Além disso, foram observados menores níveis séricos de 25 (OH) D entre aqueles com excesso de peso, obesidade abdominal e hipercolesterolemia [41].…”

“…Além disso, foram observados menores níveis séricos de 25 (OH) D entre aqueles com excesso de peso, obesidade abdominal e hipercolesterolemia [41]. Essa relação pode ser justificada pelo depósito de 25 (OH) D nos adipócitos, diminuindo sua biodisponibilidade e desencadeando uma cascata de reações hormonais que resultam em aumento da fome e diminuição do gasto energético [42].…”