Endocrine Abstracts

Type 1 diabetes mellitus (T1D) is caused by a process of altered humoral and cellular immunity, resulting in the destruction of insulin-producing cells. VD(25(OH)D³) insufficiency is implied as risk factor for T1D, while VD substitution in infantry is associated with a reduced T1D incidence. In T1D daily insulin injection is required for a stable glucose homeostasis and insulin demand rises by a higher Body Mass Index (BMI). Today there are no studies investigating the relations between endogenous VD production and insulin demand in T1D.

Methods: Twenty-nine T1D patients were examined for insulin demand (Carbohydrate Factor-IU/12 g carbohydrates (CF); basal insulin-IU/d), BMI (kg/m²) and VD (ng/ml). For our study we used the Mann-Whitney U and Spearman’s tests.

Results: The median VD was 18.7. Six patients (20.68%) were VD deficient (<10), 16 (55.17%) insufficient (<20) and 13 (44.82%) sufficient (>20). Interestingly, CF in the afternoon was significantly higher in the group with VD<20 than in the group>20(2 vs 1.25; P=0.03). CF in the morning and basal insulin exhibited a trend to be higher in the group with VD<20 compared to the group with VD>20(2 vs 1.3 and 18.1 vs 17.65; P=0.09 and P=0.15 respectively.). Furthermore the median BMI was 24.8, so we divided our patients in 2 groups (BMI<24.8>respectively.). The VD levels did not differ between the group (P=0.96). The basal insulin demand was significantly higher in the group with a BMI>24.8 compared to the group with a BMI<24.8(15 vs 21.4; P=0.01). A significant negative correlation between CF in the morning, basal insulin demand and VD levels was proven in the group with BMI>24.8 (P<0.05, rho=−0.57 respectively.), whereas in the group with a BMI<24.8 there were no significant correlations.

Conclusion: In our study lower VD levels were associated with a higher insulin demand; in preadipose T1D patients there was a significant negative correlation. Interesting would be to study whether a VD substitution could decrease insulin demand as an option for an adjunctive therapy of T1D.