Vitamin D status in children with intractable epilepsy, and impact of the ketogenic diet

Purpose: The aim of this study was to describe vitamin D status in children with intractable epilepsy prescribed newer antiepileptic drugs (AEDs) before initiation of and during 15-month treatment with the ketogenic diet (KD). Methods: Serum vitamin D (25-OHD and 1,25-OHD) and parathyroid hormone (PTH) were assessed in prepubertal children with intractable epilepsy before initiation of and during KD therapy. Three-day weighed dietary records including KD and vitamin and mineral supplementation were obtained at baseline and at 1 month. Results: Forty-five children (aged 5.1 +/- 2.7 years) were enrolled. Before KD therapy, 4% had deficient and 51% had insufficient serum 25-OHD levels. Vitamin D intake was less than recommended in 47%. Adequate vitamin D intake, fewer AEDs, and generalized seizures were associated with higher serum 25-OHD levels (p < 0.01). After 3 months on the KD, 25-OHD levels increased (p < 0.001), and PTH declined (p < 0.001). Over the next 12-month period, 25-OHD levels steadily declined (p < 0.001), and PTH did not significantly change. Conclusions: Children with intractable epilepsy treated with newer AEDs had poor vitamin D status. Their status improved over the first 3 months of KD therapy with vitamin D supplementation and slowly declined thereafter.