The association between ketoacidosis and 25(OH)-vitamin D levels at presentation in children with type 1 diabetes mellitus

Background:  There is considerable evidence supporting the role of vitamin D deficiency in the pathogenesis of type 1 diabetes mellitus (T1DM). Vitamin D deficiency is also associated with impairment of insulin synthesis and secretion. There have been no formal studies looking at the relationship between 25(OH)-vitamin D₃ and the severity of diabetic ketoacidosis (DKA) in children at presentation with T1DM.
Objective:  To determine the relationship between measured 25(OH)-vitamin D₃ levels and the degree of acidosis in children at diagnosis with T1DM.
Subjects:  Children presenting with new-onset T1DM at a tertiary children's hospital.
Methods:  25(OH)-vitamin D₃ and bicarbonate levels were measured in children at presentation with newly diagnosed T1DM. Those with suboptimal 25(OH)-vitamin D₃ levels (<50 nmol/L) had repeat measurements performed without interim vitamin D supplementation.
Results:  Fourteen of the 64 children had low 25(OH)-vitamin D₃ levels at presentation, and 12 of these had low bicarbonate levels (<18 mmol/L) (p = 0.001). Bicarbonate explained 20% of the variation in vitamin D level at presentation (partial r² = 0.20, p < 0.001) and ethnic background a further 10% (partial r² = 0.10, p = 0.002). The levels of 25(OH)-vitamin D₃ increased in 10 of the 11 children with resolution of the acidosis.
Conclusions:  Acid–base status should be considered when interpreting 25(OH)-vitamin D₃ levels in patients with recently diagnosed T1DM. Acidosis may alter vitamin D metabolism, or alternatively, low vitamin D may contribute to a child's risk of presenting with DKA.