Bone Abstracts

Objectives: The aim is to examine the serum levels of 25(OH)vitamin D in children and adolescents with type 1 diabetes mellitus and in healthy controls and to determine whether patients with diabetes have higher prevalence of vitamin D deficiency/insufficiency and whether it is correlated to its metabolic control.

Methods: A cross-sectional study of 73 patients (35 males) aged 11.84±4.44 years and 27 healthy controls (15 males), aged 7.36±4.71 years. The participants are divided in two subgroups according to the month the sample was taken – May–September and October–April. Patients are divided in two subgroups according to their metabolic control: good (HbA1c≤7.5%) and poor (HbA1c>7.5%). Levels of 25(OH)vitamin D were determined by electrochemiluminescence detection technology. The statistical methods used are Mann–Whitney and Kruskal–Wallis tests.

Results: There is no statistically significant difference between 25(OH)vitamin D levels in diabetic patients and in controls (P=0.783). The mean level of 25(OH)vitamin D in patients is slightly higher – 25.39±8.14 ng/ml than in controls – 24.44±11.88 ng/ml. The mean levels of 25(OH)vitamin D are higher in the period with more outdoor sunlight. In May-September period – 29.01±9.2 ng/ml in patients (n=28) and 29.85±8.42 ng/ml (n=9) in controls, for October-April period 25(OH)vitamin D levels are 23.14±6.55 vs 21.74±12.63 ng/ml for patients (n=45) and controls (n=18) respectively. We use US Endocrine Society guideline to define vitamin D deficiency and insufficiency as 25(OH)vitamin D level ≤20 and 21–29 ng/ml respectively. 36% of all patients (n=26) and 33% of controls (n=9) have vitamin D deficiency. Vitamin D insufficiency is observed in 37% of patients (n=27) and 37% of controls (n=10).

Mean level of HbA1c in good control group (n=16) is 7.05±0.33%, in poor control group(n=39) – 9.18±1.36%. No correlation between metabolic control and vitamin D levels is found. Level of 25(OH)vitamin D are 25.86±7.29 and 25.56±8.23 ng/ml respectively (P=0.476).

Conclusions: Presence of diabetes mellitus type 1 does not influence vitamin D metabolism. Our results show no significant differences between 25(OH)vitamin D levels in diabetic patients and in healthy controls. Vitamin D deficiency is slightly but not significantly prevalent in diabetic patients and is almost equal to that observed in healthy Bulgarian adults.

Supported by Grant from Medical University Sofia, Bulgaria.