A study of vitamin D status in Egyptian pediatric epileptic patients on monotherapy antiepileptic drugs: a hospital-based study

Introduction and aim
Epilepsy is a chronic condition with an incidence of 4–10/1000 worldwide. Antiepileptic drugs (AEDs) remain the mainstay of treatment for epilepsy. AEDs in common use are carbamazepine (CBZ), phenytoin, phenobarbitone, and sodium valproate. Long-term therapy by AEDs is associated with bone disorders, affected by both duration and dose of these drugs. The effect of antiepileptic on serum vitamin D levels is controversial and uncertain, so further clinical studies to ascertain the effect of old and newer AEDs on serum levels of vitamin D level in epileptic patients are needed, thus accomplishing a suitable usage of vitamin supplementation. The aim of this study is to assess the longitudinal effect of AEDs on serum 25-hydroxyvitamin D [25(OH) D] levels and bone mineral metabolism markers among Egyptian pediatric epileptic patients on monotherapy AEDs.
Participants and methods
The study was carried out on 62 epileptic patients attending the Neuropediatric Outpatient Clinic, Children's Hospital Cairo University, with history of seizures (age ranges from 1 year up to 12 years), and 64 children not on AEDs as a control group. Daily dietary intake of calories, calcium, and phosphorus was characterized by dietary recall method. Patients on valproate were 37.1% of patients, whereas 32.3% were on levetiracetam and 30.6% were on CBZ. Valproate dose ranged between 10 and 40 mg/kg/day, with a mean dose of 30.4 ± 8.1 mg/kg/day, whereas levetiracetam dose ranged between 20 and 50 mg/kg/day, with a mean dose of 26 ± 8.8 mg/kg/day, and CBZ dose ranged between 15 and 40 mg/kg/day, with a mean dose of 31.8 ± 8.9 mg/kg/day. All patients on AED and control group were evaluated for vitamin D level. Serum calcium, phosphorus, Mg, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatinine, and urea were measured for both patient and control groups.
Results
Marked vitamin D deficiency was detected in 31 epileptic patients (50%) (mean ± SD: 13.4 ± 7.6 ng/ml) compared with the control group (6.2%) (mean ± SD: 60.4 ± 17.9 ng/ml) ( = 0.000), whereas mild deficiency was remarkable in 19 patients with epilepsy (30.6%) compared with five (7.8%) controls. Overall, 54.8% of the severely deficient patients in vitamin D were on CBZ, whereas 41.9% were on valproate, and 3.2% were on levetiracetam, with statistical significance on comparing vitamin D level with the type of AEDs ( < 0.0005). Laboratory data showed that there was a statistically significant difference in calcium, phosphorus, Mg, and alkaline phosphatase (ALP) levels comparing epileptic patients with the control group ( < 0.000, 0.000, 0.048, and 0.000, respectively).