Vitamin D supplementation for bone health in adults with epilepsy: A systematic review

Several antiepileptic drugs (AEDs) have been associated with a detrimental effect on bone health through a reduction in serum vitamin D. Subsequently, several studies have investigated the effect of vitamin D supplementation in persons with epilepsy being treated with AEDs. The present systematic review of published literature was conducted to determine the effect of vitamin D intervention on bone health in adults with epilepsy.

The following databases were searched using keywords including but not limited to epilepsy, bone, and vitamin D: PubMed, Medline, Embase, Scopus, Cochrane Clinical Trials, International Pharmaceutical Abstracts, Health Canada Clinical Trials Database, ClinicalTrials.gov, EU Clinical Trials, and Google. Studies were eligible if there was an epilepsy diagnosis, participants were adults (18+ years old), and vitamin D treatment and bone outcome were provided. Articles were screened independently by 2 reviewers. Methodological quality was assessed using the Cochrane Collaboration's tool and a modified Newcastle Ottawa Scale for nonrandomized studies.

Nine studies were found to be eligible for this review. After vitamin D treatment, there appeared to be positive changes in bone turnover markers; 3 of 8 studies found the increase in serum calcium to be significant, 6 of 8 studies found the decrease in alkaline phosphatase to be significant, and 2 of 4 studies found the decrease in parathyroid hormone to be significant. All 6 studies that investigated bone mineralization had significant findings; however, due to varying methodologies, the impact of vitamin D on bone mineralization was inconclusive.

Vitamin D does appear to have some benefit to bone health in adults with epilepsy, and therefore supplementation could potentially be a requisite to using some AEDs. To clarify the role of vitamin D supplementation to manage the adverse effect of AEDs on bone health in adults with epilepsy, long-term trials that use higher doses (>1800 IU) and measure bone mineral density are necessary.