Vitamin D Deficiency in Pediatric Oncology Patients: A Single-Center Experience in Saudi Arabia.

Background There is a lack of local studies on vitamin D deficiency in children with cancer. This study aims to estimate the prevalence of vitamin D deficiency in the pediatric oncology population at King Abdul-Aziz Medical City (KAMC) in Jeddah, addressing knowledge gaps for improved clinical practice and future research. Methods This retrospective observational study was conducted from 2016 to 2021 at the pediatric oncology clinic in National Guard Hospital, Jeddah. The study focused on children aged 14 or younger at cancer diagnosis, data encompassed patient demographics, cancer details, and treatment information, including serum measurements of vitamin D (25(OH)D, calcium, phosphate, alkaline phosphatase). Vitamin D levels were categorized as deficient (<25 ng/ml), insufficient (25-49 ng/ml), sufficient (≥50- 125 ng/ml), or hypervitaminosis (>125 ng/ml), based on our center reference range and the validation of the assay. Results In this retrospective study of 155 pediatric oncology patients, the majority aged 0 to 10 years (78%), findings reveal a male preponderance (54.2%) and a more prevalent in patients with hematological malignancies (85%). Chemotherapy was administered to 98%, with 7% underwent radiotherapy, and 89% received steroids. Analysis of serum 25-OH vitamin D levels indicated an overall deficiency and insufficiency at diagnosis (63%) and post-therapy (43%). Age and gender had a significant influence on vitamin D levels at diagnosis, with older children and females exhibiting lower concentrations. However, these differences diminished by the end of therapy. Notably, hematological malignancy patients often presented insufficient vitamin D levels, while solid tumor patients frequently had sufficient levels. Clinical outcomes showed a high survival rate (90.7%), limited bone density assessments (18.1%), and a 14.2% prevalence of hypervitaminosis. Conclusion In summary, our study reveals that over two-thirds of pediatric oncology patients experience vitamin D deficiency and insufficiency at the time of diagnosis, particularly notable in females and older children. Notably, those with solid tumors exhibit higher baseline 25-OH vitamin D concentrations compared to counterparts with hematological malignancies. The findings underscore the importance of educating both patients and caregivers on supplementation and sun exposure to mitigate the prevalence of deficient and insufficient vitamin D levels in pediatric oncology cases.