Vitamin D deficiency increases with age and adiposity in Emirati children and adolescents irrespective of type 1 diabetes mellitus: a case control study.

BACKGROUND: Association of vitamin D (25(OH)D) deficiency with obesity and diabetes has been well-established in paediatric and adult populations. This study aims to report the association of 25(OH)D deficiency with body composition and prevalence of 25(OH)D deficiency in Emirati children and adolescents, who attended a diabetes centre in the United Arab Emirates. METHODS: Using Abu Dhabi Diabetes and Obesity Study cohort, type 1 diabetes (T1D) and normoglycaemic (NG) participants between 4-19 years of age were selected. WHO criteria were used to define 25(OH)D cut-offs: deficient (< 30 nmol/L), insufficient (30-50 nmol/L) and sufficient (> 50 nmol/L). Based on CDC recommendations, BMI percentile was categorised as underweight, normal weight, overweight and obesity. RESULTS: After age and sex matching, 148 T1D cases and 296 NG controls were identified. 25(OH)D deficiency was observed in 22.3% (n = 33) T1D and 40.5% (n = 120) NG participants. 25(OH)D levels were lower in adolescents (15 - 19 years) than children (4 - 7 years) in both T1D and NG groups (p = 0.018 vs p < 0.001). Females were more likely to be 25(OH)D deficient in both groups. Children and adolescents with BMI ≥ 95th percentile were more likely to be 25(OH)D deficient than those with normal weight (OR: 2.69; 95% CI: 1.56, 4.64). Adiposity measures and 25(OH)D levels correlated negatively in both groups (T1D p < 0.01, NG p < 0.001). CONCLUSION: Vitamin D 25(OH)D deficiency is notably prevalent in Emirati children and adolescents despite adequate sunlight throughout the year. The prevalence was lower in those with T1D which may be indicative of treatment compliance in this population. This study also confirms important negative association of serum 25(OH)D levels with body mass and obesity in this population.