Effect of Ionic Calcium and Vitamin D3 in Lumbar Spine Bone Mineral Density of Paediatric Epileptic Patients on Antiepileptic Drugs

Abstract

Introduction: Epilepsy is one of the most common neurologic conditions occurring in persons under 21 years of age. Vitamin D deficiency is highly prevalent among children with epilepsy. Antiepileptic drugs (AEDs) are associated with decreased Bone Mineral Density (BMD) as AEDs increase catabolism of 25-hydroxy vitamin D by induction of the hepatic P 450 enzyme system, which leads to relative hypocalcaemia, increased levels of parathyroid hormone (PTH) and subsequently low BMD. Aim: To evaluate the association of ionic calcium and vitamin D3 in paediatric epileptic patients who were on AEDs with BMD. Materials and Methods: This was an observational cross-sectional study carried out at Department of Paediatrics, SPMC, Bikaner, Rajasthan, India from December 2020 to November 2021. A total of 150 epileptic patients aged 5 to 15 years who were on AED therapy for more than six months and a comparable group of 130 age and gender matched healthy individuals participated in this study. Serum vitamin D3, Alkaline Phosphatase (ALP), ionic calcium and phosphorous levels were assessed and compared between both the groups. Using OSTEOPRO DEXA BMD at the lumbar spine was calculated. Mann-Whitney test and t-test were used to compare quantitative data whereas Chi-square test was used to compare qualitative data in two groups. Non parametric tests (Spearman Correlation) were used to explore the correlation between the two variables. The p-value of <0.05 was considered to be statistically significant. Results: The mean age of study group and control group were 9.94±2.61 years and 10.09±2.53 years respectively. Mean serum ionic calcium (1.09±0.13 mmol/L) was significantly lower in study group as compared to controls (1.15±0.13 mmol/L) with p-value <0.001. Mean serum phosphorous and serum ALP levels were not significantly different in study and control group. The mean Vitamin D3 level (16.70±5.35 ng/mL) was lower in children receiving AEDs as compared to controls (19.08±5.39 ng/mL) with p-value <0.001. Serum levels of ionic calcium and Vitamin D3 were found to be significantly lower in groups with polytherapy and enzyme inducer group of AEDs (p<0.05) whereas only statistically significant difference in vitamin D3 was found in subjects with more than two years of AED therapy. The mean Lumbar Spine Bone Mineral Apparent Density (LSBMAD) of the study and control group were 0.47±0.14 g/cm² and 0.61±0.12 g/cm² respectively. Conclusion: Epileptic children receiving multiple drugs for longer duration showed more decline in calcium and serum 25 hydroxy vitamin D compared to those with single drug for shorter duration.