Association of antiepileptic drugs, vitamin D, and calcium supplementation with bone fracture occurrence in epilepsy patients.

The aim of this study is to determine whether calcium and vitamin D supplementation reduces the risk of bone fractures in adult epilepsy patients. Records were obtained on 7716 patients with epilepsy prescribed antiepileptic drugs (AED) from the Veteran Affairs Hospital in Lexington, Kentucky. We performed a single center, retrospective cohort study to examine the proportion of fractures in 3303 patients on AED who took supplements compared to patients on AED not taking supplements. Patients prescribed long-term AEDs taking calcium and vitamin D were as likely to have fractures as those who did not take these supplements (11.7% vs. 9.9%, χ(2)=0.59, p=0.44). Phenytoin use was associated with a statistically significant increased risk of fractures OR=1.55 (1.10-2.24). Thus, in this group of patients with epilepsy on AED, bone fractures were not prevented in individuals taking calcium and vitamin D supplementation.