Neurology department, Coimbra University and Hospital Centre,
Faculty of Medicine of the University of Coimbra,
Rheumatology department, Coimbra University and Hospital Centre,
Clinical Pathology department, Coimbra Universitary and Hospital Centre, Coimbra, Portugal
Correspondence: Inês Antunes Cunha
Coimbra University and Hospital Centre,
Praceta Mota Pinto 3004-561,
Objective. The epilepsy-related risk factors for vitamin D deficiency, particularly the use of enzyme-inducing antiepileptic drugs (EIAEDs), and how to treat vitamin D deficiency in patients with epilepsy remain unclear. Our aims were to explore risk factors and the influence of EAIEDs in vitamin D status and to determine the efficacy of a daily dose of oral cholecalciferol (vitamin D3) in epileptic patients with vitamin D deficiency.
Methods. Clinical data were collected and 25-hydroxyvitamin D (25(OH)D) serum levels were measured. All patients with vitamin D deficiency (25(OH)D ≤20 ng/mL) or insufficiency (25(OH)D from 21-29 ng/mL) were treated with 6,670 IU/day cholecalciferol
for eight weeks and 25(OH)D was then remeasured. Descriptive and inferential statistics were employed.
Results. A total of 92 patients (44.6% males), with mean age of 41.0±14.8 years, were included. Measurements of 25(OH)D revealed that 79.3% patients had abnormal levels: 56.5% were vitamin D deficient and 22.8% were vitamin D insufficient. The statistically significant risk factors for vitamin D deficiency identified were: number of AEDs, treatment with EIAEDs, low sun exposure, high body mass index (BMI) and a high frequency of epileptic seizures. After treatment, 25(OH)D mean level increased by 98.99% (regardless of EIAED use or being overweight).
Significance. In our sample, more than half of the adults with epilepsy showed 25(OH) D deficiency. Patients on EIAEDs had lower 25(OH)D levels. A daily dose of 6,670 IU cholecalciferol successfully led to the correction of 25(OH)D levels. A higher dose in obese patients or in patients taking EIAEDs may not be warranted and this should be considered in future guidelines for routine vitamin D deficiency treatment.