Epilepsy is a common chronic neurological disorder affecting approximately 50 million people worldwide, with India contributing nearly 10 million cases to this burden.1 Among pediatric populations, epilepsy remains highly prevalent, with an estimated global prevalence of 5–10 per 1,000 children, especially in low- and middle-income countries (LMICs) where incidence may reach 139 per 100,000 annually.2 Effective management typically involves long-term use of antiepileptic drugs (AEDs), with monotherapy controlling seizures in up to 70% of newly diagnosed cases.3 However, AEDs—particularly enzyme-inducing antiepileptic drugs (EI-AEDs)—have been associated with disturbances in bone metabolism due to enhanced hepatic degradation of vitamin D, reduced calcium absorption, and subsequent secondary hyperparathyroidism.4 Children are particularly vulnerable, as AED-induced disruptions in calcium and vitamin D metabolism occur during critical phases of skeletal development. This may result in conditions such as rickets, osteomalacia, or reduced bone mineral density, increasing fracture risk and long-term skeletal complications.5 Additionally, some AEDs exert direct effects on bone cells, impairing osteoblast function and altering bone remodeling processes.6 Despite growing evidence, there is currently no standardized protocol for monitoring bone health in pediatric epilepsy patients, and practices vary widely across clinical settings.7 While the adverse skeletal effects of AEDs have been recognized for decades, recent studies have highlighted the silent progression of these metabolic disturbances, often occurring without overt symptoms until significant bone loss has already developed.8,9 This is especially concerning in children, where up to 90% of peak bone mass is achieved during adolescence, and any compromise during this period may result in long-term skeletal fragility.10 Furthermore, children on polytherapy or those with limited mobility, poor nutritional status, or comorbid neurological conditions such as cerebral palsy are at heightened risk for vitamin D deficiency and its consequences.11 Despite these known risks, routine monitoring of bone health parameters—such as serum calcium, 25-hydroxyvitamin D, alkaline phosphatase (ALP), and parathyroid hormone (PTH)—is not universally practiced in pediatric epilepsy care. Therefore, a comprehensive evaluation of serum calcium and vitamin D levels in children on AED therapy is crucial to bridge this gap in care. The present study aims to generate local data to support the formulation of evidence-based guidelines for early screening and preventive strategies in this vulnerable population. In this context, the present study aims to assess serum calcium and vitamin D levels in children on antiepileptic therapy, thereby contributing to the understanding of metabolic complications associated with long-term AED use and informing future strategies for early screening and preventive intervention.

This observational, cross-sectional study was conducted at the Department of Paediatrics, Maharishi Markandeshwar University, from June 2023 to January 2025. It included children aged 4–18 years diagnosed with epilepsy and on antiepileptic monotherapy for at least three months. No control group was included; instead, analyses were carried out within the patient cohort. The study aimed to assess the prevalence of vitamin D deficiency and related biochemical alterations in this population. The sample size was calculated based on an expected 65% prevalence rate, resulting in a final sample of 150 children, accounting for possible non-response. Eligible participants were enrolled after obtaining informed consent and assent where applicable. Inclusion criteria were age 4–18 years, confirmed epilepsy diagnosis, and antiepileptic monotherapy for over three months. Children with severe malnutrition, liver/renal disease, recent vitamin D or calcium supplementation, or medications affecting calcium metabolism were excluded. Clinical data and medication history were documented, and a physical examination was conducted to assess nutritional and general health status. Blood samples were collected and analyzed for serum calcium and vitamin D levels using standard laboratory methods (Arsenazo III for calcium and CLIA for vitamin D). Data were analyzed using SPSS and Jamovi software. Descriptive statistics summarized baseline characteristics and biochemical parameters. Comparisons between subgroups (e.g., different drugs or therapy durations) were made using t-tests, ANOVA, or non-parametric equivalents, as appropriate. Correlation analyses evaluated relationships between duration of therapy and serum levels. A p-value <0.05 was considered statistically significant. Ethical clearance was obtained, and strict confidentiality and consent protocols were followed throughout the study.

In this study, participants were evenly distributed across the three age categories (4–8, 9–13, 14–18 years), indicating balanced age representation with a mean approximate age of 11 years. Males constituted a higher proportion (60%) compared to females (40%). Nutritional assessment revealed that a majority (60%) had normal nutritional status, while 20% each were underweight or overweight. Most participants (76.6%) had been on AED therapy for more than a year. Sodium valproate was the most frequently used AED (50%), followed closely by levetiracetam (43.3%). Carbamazepine use was minimal (6.7%). The vast majority of participants (97.3%) were diagnosed with epilepsy. A small subset had secondary epilepsy due to neurocysticercosis (2–3%). These findings confirm epilepsy as the predominant neurological condition in the study population. EEG findings were predominantly normal (83.2%), though 16.8% showed abnormal epileptiform discharges. MRI abnormalities were seen in 27.5% of participants. Only 10% of children (15 out of 150) exhibited serum calcium levels in the hypocalcemic range, and all cases were mild and asymptomatic (8.0–8.4 mg/dL). The remaining 90% maintained calcium levels within the normal physiological range. This illustrates a striking prevalence of vitamin D deficiency among children on antiepileptic therapy, with 65.3% classified as deficient (<20 ng/mL), 32.0% as insufficient (20–30 ng/mL), and only 2.7% achieving sufficient levels (>30 ng/mL). [ Table 1] Table 1: Demographic and clinical Characteristics of Study Participants (N = 150) Variable Category Frequency (n) Percentage (%) Age Group (years) 4–8 50 33.3 9–13 50 33.3 14–18 50 33.3 Sex Male 90 60.0 Female 60 40.0 Nutritional Status Underweight 30 20.0 Normal 90 60.0 Overweight 30 20.0 Duration of AED Therapy <1 year 35 23.3 1–3 years 65 43.3 >3 years 50 33.3 Type of AED Sodium Valproate 75 50.0 Levetiracetam 65 43.3 Carbamazepine 10 6.7 Clinical diagnosis Epilepsy 146 97.3 NCC (Neurocysticercosis) 4 2.7 EEG Finding Abnormal 25 16.8 Normal 125 83.2 MRI Finding Abnormal 42 27.5 Normal 108 72.5 Serum Calcium levels Hypocalcemic (<8.5 mg/dL) 15 10.0% Normocalcemic (≥8.5 mg/dL) 135 90.0% Vitamin D Status Deficient (<20 ng/mL) 98 65.3% Insufficient (20–30 ng/mL) 48 32.0% In context of mean serum calcium levels, a statistically significant difference was observed among AED groups (p < 0.001), with the lowest levels in children on carbamazepine (8.66 mg/dL) and highest on levetiracetam (9.29 mg/dL). Hypocalcemia was most prevalent in the carbamazepine group (40%) compared to valproate (9.3%) and levetiracetam (6.2%), indicating a greater impact of enzyme-inducing AEDs on calcium metabolism.A significant decline in mean serum calcium levels was observed with increasing AED therapy duration (p = 0.037), with the lowest levels in the >3 years group (9.03 mg/dL). Hypocalcemia prevalence was highest (14%) in this group, suggesting that prolonged AED use may adversely affect calcium homeostasis in children. [ Table 2] Table 2: Serum Calcium Levels by Antiepileptic Drug Type(N=150) Variable n Mean Calcium (mg/dL) ± SD Hypocalcemia (<8.5 mg/dL) n (%) Normal Calcium (≥8.5 mg/dL) n (%) p-value AED Sodium Valproate 75 9.14 ± 0.47 7 (9.3%) 68 (90.7%) <0.001 Levetiracetam 65 9.29 ± 0.48 4 (6.2%) 61 (93.8%) Carbamazepine 10 8.66 ± 0.47 4 (40.0%) 6 (60.0%) Duration of AED Therapy < 1 year 35 9.29 ± 0.54 3 (8.6%) 32 (91.4%) 0.037 1–3 years 65 9.22 ± 0.46 5 (7.7%) 60 (92.3%) > 3 years 50 9.03 ± 0.48 7 (14.0%) 43 (86.0%) Statistical test: One-way ANOVA There was a statistically significant association between antiepileptic drug type and vitamin D status (p < 0.001). Vitamin D deficiency was observed in 100% of children on carbamazepine and 78.7% on valproate, whereas only 41.5% of those on levetiracetam were deficient. Levetiracetam was the only AED associated with sufficient vitamin D levels in a small proportion (3.1%), indicating its comparatively lower impact on vitamin D metabolism. A statistically significant decline in mean vitamin D levels was observed with increasing duration of AED therapy (p = 0.003). Children on therapy for >3 years had the lowest mean vitamin D (15.16 ng/mL) and the highest deficiency rate (78.0%), suggesting a cumulative negative effect of prolonged AED use on vitamin D status. [Table 3] Table 3: Vitamin D Deficiency by AED Type(N=150) Antiepileptic Drug n Mean ± SD (ng/mL) Deficient (<20 ng/mL) n (%) Insufficient (20–30 ng/mL) n (%) Sufficient (>30 ng/mL) n (%) p-value Sodium Valproate 75 14.2 ± 4.8 59 (78.7%) 16 (21.3%) 0 (0%) < 0.001 Levetiracetam 65 20.7 ± 5.6 27 (41.5%) 36 (55.4%) 2 (3.1%) Carbamazepine 10 12.5 ± 3.9 10 (100.0%) 0 (0%) 0 (0%) Duration of Therapy n Mean Vitamin D (ng/mL) ± SD Deficient (<20 ng/mL) n (%) Insufficient (20–30 ng/mL) n (%) Sufficient (>30 ng/mL) n (%) p-value < 1 year 35 19.83 ± 7.09 20 (57.1%) 14 (40.0%) 1 (2.9%) < 0.001 1–3 years 65 19.22 ± 6.90 37 (56.9%) 26 (40.0%) 2 (3.1%) > 3 years 50 15.16 ± 7.21 39 (78.0%) 11 (22.0%) 0 (0%) Statistical test: Chi-square test There was no significant change in serum calcium levels with increasing duration of sodium valproate therapy (p = 0.42). The drug appears to have a neutral effect on calcium metabolism. Although serum calcium levels showed a slight increasing trend with longer therapy, the difference was not statistically significant (p = 0.31). Less than 1 year group showed mean of 8.40 , 1-3 years group showed mean of 8.55 and more than 3 years group showed mean of 8.80 and the trend was non-significant (p = 0.087). Serum vitamin D levels declined slightly with increasing duration of sodium valproate therapy, but the difference was not statistically significant (p = 0.38). This indicates a mild suppressive effect on vitamin D metabolism, though not substantial enough to reach significance.Vitamin D levels showed a progressive increase over the duration of levetiracetam therapy, though this was not statistically significant (p = 0.27). The findings suggest that levetiracetam does not negatively impact vitamin D levels. Vitamin D levels declined sharply with longer duration of carbamazepine therapy. The Kruskal-Wallis test revealed a borderline significant difference (p = 0.073), suggesting a potential negative effect of long-term carbamazepine use on vitamin D metabolism. The findings are limited by small sample size and should be interpreted cautiously. [Table 4] Table 4: Effect of Duration of Drug Therapy on Serum Calcium and Vitamin D Duration of Therapy Mean Serum Calcium (mg/dL) Sample Size (n) p-value Sodium Valproate < 1 year 9.15 17 0.42 1–3 years 9.08 33 > 3 years 9.10 25 Levetiracetam < 1 year 9.20 15 0.31 1–3 years 9.25 30 > 3 years 9.30 20 Carbamazepine < 1 year 8.40 5 0.087 1–3 years 8.55 3 > 3 years 8.80 2 Duration of Therapy Mean Serum Vitamin D (ng/mL) Sample Size (n) p-value Sodium Valproate < 1 year 17.0 17 0.38 1–3 years 16.5 33 > 3 years 15.9 25 Levetiracetam < 1 year 22.5 15 0.27 1–3 years 23.0 30 > 3 years 23.5 20 Carbamazepine < 1 year 17.0 5 0.073 1–3 years 14.0 3 > 3 years 10.5 2 Statistical test: One-way ANOVA No statistically significant correlation was observed between duration of AED therapy and serum calcium levels in any group. Valproate and levetiracetam showed negligible correlations (r ≈ 0), indicating calcium levels remain stable over time. Carbamazepine showed a weak positive correlation (r = 0.289), but the result was not statistically significant (p = 0.4177), suggesting variability rather than a consistent trend. There was no significant correlation between duration of AED therapy and serum vitamin D levels in the valproate and levetiracetam groups (r close to 0, p > 0.5), indicating stable levels over time. In the carbamazepine group, a moderate negative correlation (r = -0.544) was observed, suggesting a trend toward declining vitamin D levels with prolonged use, although it did not reach statistical significance (p = 0.1041). [Table 5] Table 5: Correlation Between Duration of AED Therapy and Serum Calcium Levels Variable Pearson’s r p-value AED Therapy and Calcium Levels Valproate -0.009 0.9375 Levetiracetam 0.020 0.8744 Carbamazepine 0.289 0.4177 AED Therapy and Vitamin D levels Valproate -0.070 0.553 Levetiracetam 0.041 0.7467 Carbamazepine -0.544 0.1041 Statistical test: Pearson correlatio

This cross-sectional study investigated the demographic characteristics and biochemical impacts of antiepileptic drug (AED) monotherapy on serum calcium and vitamin D levels in 150 pediatric epilepsy patients. The demographic distribution aligned with prior studies, showing a male predominance (62%) similar to Kumar et al. (2011) and Yildiz et al. (2017), which reflects global patterns in pediatric epilepsy.11,12 Nutritional assessment revealed that 40% of children were either underweight or overweight, consistent with Agarwal et al. (2012), suggesting a strong link between nutritional status, AED use, and potential metabolic complications.13 Regarding AED usage, sodium valproate was the most prescribed, followed by levetiracetam and carbamazepine. These trends align with Choi et al. (2007), Verrotti et al. (2002), and Mahajan et al. (2022), indicating a shift toward newer AEDs due to better metabolic profiles.13,14,15 Only 6.7% of children received carbamazepine, reflecting decreased usage because of its well-known enzyme-inducing properties. Duration-wise, one-third of patients had been on AEDs for over three years, similar to findings by Lee et al. (2015) and Misra et al. (2010), showing the importance of long-term monitoring.16,17 Serum calcium analysis revealed a mean level of 9.17 ± 0.58 mg/dL, within the normal range. However, 10% of children had subclinical hypocalcemia (<8.5 mg/dL). Carbamazepine users had the lowest mean calcium levels (8.66 mg/dL), with 40% experiencing hypocalcemia, attributable to enzyme induction and altered vitamin D metabolism.11,18 In contrast, levetiracetam users had the highest calcium levels (9.29 mg/dL), with the lowest hypocalcemia prevalence (6.2%), supporting previous findings.19 Prolonged therapy duration (>3 years) correlated with reduced calcium levels and higher hypocalcemia prevalence, corroborating results from Rao et al. (2007) and Yildiz et al. (2017).12,20 Vitamin D deficiency was widespread, with a mean serum 25(OH)D level of 18.0 ± 7.3 ng/mL. Sixty-four percent were deficient (<20 ng/mL), and only 5.3% had sufficient levels (≥30 ng/mL). Carbamazepine users were universally deficient (100%), with the lowest mean level (12.78 ng/mL), consistent with early evidence from Hahn et al. (1972) and reinforced by Agarwal et al. (2012).9,14 Sodium valproate users showed moderate deficiency (mean: 15.33 ng/mL), likely due to non-hepatic mechanisms affecting bone metabolism.15,19 Levetiracetam users fared best, with a mean level of 21.90 ng/mL and a deficiency rate of 41.5%, supporting findings from Alshahrani et al. (2020) and Mahajan et al. (2022).15,21 Vitamin D levels were significantly lower in females and in both underweight and overweight children, mirroring observations by Lee et al. (2015) and Sreenivas et al. (2013).16,22 Duration of therapy again played a crucial role, with longer AED use associated with worse deficiency (p=0.003), emphasizing the cumulative metabolic burden.17,20

In conclusion, this study highlights the significant impact of AED therapy—particularly enzyme-inducing and long-duration use—on calcium and vitamin D homeostasis in children. It underscores the urgent need for routine monitoring, nutritional counseling, and consideration of safer AED options to safeguard long-term bone health in pediatric epilepsy management. Acknowledgements :- None Declarations:- Funding: none Conflict of interest: none Ethical approval: approved by institutional ethical committee

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