Bone mineral density loss in ambulatory children with epilepsy in spite of using supplemental vitamin D in Southern Iran: a case–control study

Epilepsy might have adverse effect on bone density due to underlying disease, drugs, vitamin D deficiency, immobilization and malnutrition. We investigated the bone mineral density in ambulatory vitamin-D supplemented children with epilepsy. This case–control study was conducted on 90 epileptic children aged 11.4 ± 3.3 years, and age and gender matched controls in pediatric neurology clinics of Shiraz, in Southern Iran, 2016. Anthropometric measurements, puberty, sun exposure, physical activity and biochemical variables were assessed. Bone mineral density was evaluated by dual-energy X-ray absorptiometry method. Data were analyzed by SPSS.v21. Prevalence of low bone mass in femur was more in patients (27%) than the controls (9%) (P value = 0.002). Age, weight Z score and height Z score were the most significant associated factors on lumbar BMD, BMAD, and femur BMD. Seizure duration and how it responded to anticonvulsants were the most associated factors with both lumbar and femur bone density. Sodium valproate and carbomazepin usage had negative association with lumbar Z score (beta = − 0.216, P = 0.017 and beta = − 0.336, P = 0.027, respectively). We hypothesized that epilepsy per se could affect bone density by an unknown pathophysiology, which was independent from vitamin D deficiency, effects of anticonvulsant and physical activity.