Association between serum vitamin D levels and age in patients with epilepsy: a retrospective study from an epilepsy center in Saudi Arabia

BACKGROUND:
Vitamin D deficiency has been linked to various medical conditions such as bone loss, decreased mineralization, endocrine disorders, and central nervous system disorders, including epilepsy. Vitamin D deficiency is prevalent among patients with epilepsy (PWE). However, the specific association between vitamin D levels and age in PWE is unclear.


OBJECTIVES:
Identify the relation between vitamin D level and age in PWE and evaluate factors that may play a role in seizure control.


DESIGN:
Retrospective analytical medical record review


SETTING:
Outpatient epilepsy research clinic in Saudi Arabia


PATIENTS AND METHODS:
Between November 2016 and April 2020, we selected eligible PWE aged older than 14 years whose vita-min D levels were recorded at least once after reviewing 1550 patient electronic files. We analyzed data on serum vitamin D level by age and other factors, vitamin D supplement use, seizure classification, and conducted a multivariate logistic regression to assess associations with seizure control.


MAIN OUTCOME MEASURES:
Relationships between vitamin D levels and age and factors that might affect seizure control.


SAMPLE SIZE:
524 patients


RESULTS:

The prevalence of low serum vitamin D levels was high (86.8%). The median vitamin D level in all patients was low (38 nmol/L), and was lower in young PWE than in adult PWE (
P
<.01). Only 146 patients received vitamin D supplements. High vitamin D levels were associated with a 40% seizure reduction.



CONCLUSION:
Vitamin D deficiency is underestimated in PWE in Saudi Arabia, and is more prevalent among young adults and patients on polytherapy than in other PWE. Patients with high vitamin D levels had good seizure control compared with those with low levels. The effect of vitamin D supplements on seizure control should be further investigated in randomized control trials.


LIMITATIONS:
Retrospective study and no categorization by presence of supplementation.


CONFLICT OF INTEREST:
None.