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

Abstract

To the Editor: In the July-August 2022 issue of the Annals of Saudi Medicine, Alhaidari et al1 studied the relationship between serum vitamin D (VD) level and age among Saudi patients with epilepsy (PWE) and evaluated factors that might control the seizures. They found a high prevalence of VD deficiency (86.8%). The median serum VD level in the studied cohort was low (38 nmol/L), and was statistically lower in young PWE compared to adult PWE (P<.01). The high serum VD levels were correlated with a 40% seizure reduction.1 Apart from a few study limitations stated by Alhaidari et al,1 we believe that the following limitation is worthy to mention. Several factors could control the cutoff values (CV) of serum VD level. These include age, gender, season, ethnicity, skin color, dietary habits, and sunlight exposure.2 Based on these factors, numerous populations-specific CV of serum VD levels have been formulated to be applied clinically and in research institutions.3,4 Saudi Arabia is among the countries that have generated their CV of serum VD levels and the recommended value for determining VD status and bone health was set at 30.0 nmol/L.5 In the study methodology, Alhaidari et al1 mentioned that serum VD level was grouped into normal (≥75 nmol/L) and low (<75 nmol/L). However, they didn’t state the reference of their utilized CV of serum VD levels. That methodological limitation might importantly query the correctness of the study results. We believe that employing local CV of serum VD level might better fill the objectives of the study by Alhaidari et al.1 Mahmood Dhahir Al-Mendalawi