Introduction

Vitamin D plays a critical role in skeletal development and calcium homeostasis during childhood. Deficiency remains prevalent globally and is associated with rickets, impaired bone mineralization, and potential extra-skeletal health effects. This article summarizes the clinical impact, high-risk populations, screening considerations, and evidence-based management strategies for vitamin D deficiency in children.

Clinical Impact of Vitamin D Deficiency

Vitamin D deficiency significantly reduces intestinal calcium absorption, often to as low as 10–15%, leading to hypocalcaemia, secondary hyperparathyroidism, and defective bone mineralization. Clinically, affected children may present with bone deformities, bone pain, delayed growth, and, in severe cases, hypocalcaemic seizures.

Beyond skeletal outcomes, observational data suggest that adequate vitamin D status may be associated with a lower risk of certain autoimmune conditions, such as type 1 diabetes, and possibly some malignancies. Evidence for neuropsychiatric effects remains suggestive rather than conclusive.

Diagnostic Thresholds

Serum 25-hydroxyvitamin D [25(OH)D] is the recommended biomarker for assessing vitamin D status:

• Deficiency: < 37.5 nmol/L (15 ng/mL)

• Insufficiency: 37.5–50 nmol/L (15–20 ng/mL)

• Sufficiency: ≥ 50 nmol/L (≥ 20 ng/mL)

High-Risk Groups

Certain pediatric populations are at increased risk of vitamin D deficiency, including:

• Exclusively breastfed infants

• Children with darker skin pigmentation

• Adolescents, particularly during periods of rapid growth

• Individuals with malabsorption disorders

Screening Recommendations

Routine population-wide screening is not universally recommended. Measurement of serum 25(OH)D should be considered in symptomatic children or those belonging to high-risk groups.

Treatment Strategies

Treatment approaches depend on severity and adherence considerations:

• Daily therapy: Vitamin D 1,000–5,000 IU/day for 2–3 months, followed by maintenance dosing (approximately 400 IU/day)

• Stoss therapy (for poor adherence): A single high oral dose of vitamin D (100,000–600,000 IU) administered over 1–5 days, followed by maintenance therapy

• Adjunctive calcium supplementation is recommended when dietary intake is inadequate

Therapeutic Monitoring

Monitoring is essential to ensure efficacy and safety:

• At 1 month: serum calcium, phosphorus, and alkaline phosphatase (ALP)

• At 3 months: serum 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, and ALP
  Radiographic evidence of healing may further confirm treatment response.

Reference: Misra et al., Pediatrics, 2008;122:398.