Vitamin D deficiency and the associated factors in children with type 1 diabetes mellitus in southern Iran

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disorder caused by destruction of beta cells of the pancreas. Several reports have suggested a connection between vitamin D deficiency and T1DM and the possible role of dietary vitamin D supplementation in reducing the risk of T1DM. There is little knowledge about the prevalence of vitamin D deficiency among Iranian children with T1DM. Serum 25-hydroxy vitamin D (25OHD) was assayed by high performance liquid chromatography in 8–18-year-old diabetic patients referred to pediatric diabetes clinics in Shiraz, Iran, during a period of 14 months. The age of the onset of T1DM, daily insulin usage, weight, height, and BMI of each patient were recorded along with levels of physical activity and sun exposure. The patients’ body composition was determined by DEXA and used in further analysis. This study was conducted on 39 diabetic boys and 46 diabetic girls aged 12.4 ± 4.2 years. Mean serum 25(OH)D3 was 18 ± 12.2 ng/dl. Serum levels of 25(OH)D3 were higher in boys than girls. 7.7 % of the boys and 30.4 % of the girls had severe vitamin D deficiency. There was a negative correlation between the age of the onset of T1DM and serum concentration of 25(OH)D3 (p = 0.006, r = −0.17). Girls with T1DM showed a higher prevalence of severe vitamin D deficiency than boys with T1DM. Moreover, vitamin D deficiency was more prevalent in individuals with earlier onset of the disease and in those with higher fat mass index.