Effect of Anti-Seizure Medication Monotherapy on Vitamin D Levels in Indian Children: A Longitudinal Cohort Study

Background and purpose: The timeline of alteration of vitamin D and calcium levels in those receiving anti-seizure medication (ASM) remains to be elucidated. To determine the changes in vitamin D levels over a period of 6 months among children receiving monotherapy with commonly used ASM.

Methods: The baseline serum levels of vitamin D, parathyroid hormone (PTH), calcium, alkaline phosphatase (ALP), phosphorus were measured in 32 children (median age 8 years) with newly diagnosed epilepsy. An appropriate ASM monotherapy was started. Those found to be deficient were treated with vitamin D supplementation. Children were reassessed after 90 days and 180 days for drug compliance and drug side-effects. All the baseline investigations were repeated.

Results: At baseline, 21.9% of children were vitamin D-deficient, with a median serum level of 19.8 ng/mL. For children who were not vitamin D-deficient (VDD) at baseline (n=25), the median (interquartile range [IQR]) vitamin D levels were found to be significantly lower than baseline after 90 days of ASM use (23.0 [18.0 to 28.9] vs. 22.0 [12.0 to 24.0]; p<0.001). After 90 days, ASMs caused notable decreases in vitamin D levels from baseline for children who were not VDD at baseline (n=25) (23.0 [18.0 to 28.9] vs. 22.0 [12.0 to 24.0]; p<0.001), alongside changes in calcium, phosphorus, PTH and ALP levels. Similarly, in children who were non-deficient at 90 days follow-up (n=20), median (IQR) vitamin D levels were found to be significantly lower at 180 days than at 90 days (24.5 [21.0 to 28.9] vs. 18.4 [13.6 to 20.6]; p<0.001).

Conclusions: The study noted vitamin D deficiency in children on ASM monotherapy for 3-6 months, emphasizing regular monitoring by clinicians.