Vitamin D profile in autism spectrum disorder children and its relation to the disease severity

To the Editor,

In their distinguished study, Mansour et al. [1] found that among Egyptian children with autism spectrum disorder (ASD), the prevalence of vitamin D (VD) insufficiency, VD deficiency, and VD sufficiency (normal serum VD levels) were 63.8%, 28.8%, and 7.4% respectively. Moreover, no association was noted between serum VD levels and childhood autism rating scale scores, language age, and diagnostic and statistical manual of mental disorders, fifth edition severity levels. As a result, they concluded that VD deficiency might contribute to ASD occurrence in genetically vulnerable children and VD therapy might be beneficial as an adjuvant treatment modality [1]. It is important to notice that accurate evaluation of the VD profile in the pediatric population to optimize bone health demands using VD reference intervals (VDRI) [2]. In many parts of the world, pediatric VDRI is characterized according to the American academy of pediatrics /LWEPS’s recommendations into the following groups for use in clinical settings and research: normal (20-100 ng/mL), insufficiency (15-20 ng/mL), deficiency (5-15 ng/mL), and severe deficiency (<5 ng/mL) [3]. In the study methodology, Mansour et al. [1] stated that they referred to the VDRI launched by Holick, which is primarily designed for the adult population [4]. The employed VDRI were the following: hazardous levels (>100 ng/ml), normal levels (30-100 ng/ml), insufficiency (20-29 ng/ml), and deficiency (<20 ng/ml) [4]. Indeed, there are significant differences between pediatric [3] and adult VDRI [4] to characterize VD profile. As a result, referring Mansour et al. [1] to adult VDRI rather than pediatric one in their study could call their findings into question.