Prevalence and risk factors for vitamin D insufficiency among 78 children with epilepsy, aged 3-17 years, treated September 2008-March 2009, were evaluated in a study at the University of Michigan, Ann Arbor, MI. Sex ratio M:F was 41:59; 81% of European origin; mean age 11.64 years. Low levels of 25-hydroxyvitamin D (<20 ng/ml) were found in 25% of the children and normal levels (> 32 ng/ml) occurred in only 25%. Girls and children with elevated body mass index were at increased risk for low 25-hydroxyvitamin D. Newer less potent enzyme-inducing antiepileptic drug use (lamotrigine, levetiracetam, oxcarbazepine, gabapentin, topiramate, vigabatrin, zonisamide) was not associated with altered risk compared with older enzyme-inducing drugs (carbamazepine, phenobarbital, phenytoin). The risk was higher for those with localization-related partial epilepsy but these patients had higher body mass index. 
COMMENT. Vitamin D insufficiency is prevalent among almost all children with epilepsy, and the risk is significantly increased for female patients and in patients with increased body mass index. Specific antiepileptic drug usage, comorbid cerebral palsy or intellectual retardation, and seizure control, potential risk factors for vitamin D insufficiency, did not contribute to the risk in this patient cohort. Patients with partial seizures were at increased risk, but the significance of this observation was confounded by the associated elevated body mass index. Prevalence of hypovitaminosis D is high in the general pediatric population, but patients with epilepsy are at additional risk for bone injury and other complications. Increased attention to vitamin D levels and more extensive use of vitamin D supplementation are warranted in children with epilepsy, especially girls and those with elevated body mass index.
In a review article on vitamin D and bone health in children with epilepsy , the authors suggest methods for vitamin D supplementation based on 25-hydroxyvitamin D levels (ng/ml), pending official guidelines. They advocate screening for vitamin D insufficiency and supplementation with cholecalciferol to maintain optimal vitamin D levels.
In an editorial, Wirrell E, Mayo Clinic, Rochester, MN,  agrees with Shellhaas and Joshi that all children with epilepsy should receive 400 JU of vitamin D and an optimal calcium intake and diet. Further, a dose of vitamin D at 1000 IU per day should be considered for children with symptomatic generalized epilepsy, those with impaired mobility, and those treated with polytherapy. Screening for vitamin D levels should be considered for all children with epilepsy. Bone mineral density screening without pathologic fracture requires further study. Vitamin D insufficiency in pediatric epilepsy appears to be neglected, probably as a result of conflicting study findings.