What is the treatment for children with vitamin D deficiency?

Treatment for Vitamin D Deficiency in Children

For children with vitamin D deficiency, initiate treatment with 2,000 IU of vitamin D3 daily for 12 weeks (or alternatively 50,000 IU every other week for 12 weeks), followed by maintenance therapy with 600 IU daily for children aged 1-18 years. 1

Initial Loading Phase

Dosing Regimens Based on Severity

• For severe vitamin D deficiency (levels <20 ng/mL): Administer 2,000 IU of vitamin D3 daily for 12 weeks, which is the standard loading regimen recommended for pediatric patients 1

• Alternative intermittent dosing: 50,000 IU every other week for 12 weeks achieves equivalent cumulative dosing and may improve adherence 1

• For mild deficiency (5-15 ng/mL): Consider 4,000 IU daily for 12 weeks or 50,000 IU every other week for 12 weeks 1

• For insufficiency (16-30 ng/mL): Use 2,000 IU daily or 50,000 IU every 4 weeks 1

Recent Evidence on Dosing Frequency

• A 2024 randomized controlled trial demonstrated that both daily (4,000 IU) and fortnightly (60,000 IU) regimens for 12 weeks are equally efficacious in treating symptomatic vitamin D deficiency in children aged 1-10 years, with all children achieving sufficiency range by 4 weeks 2

• Both regimens showed similar increases in calcium and phosphate levels, with comparable decreases in alkaline phosphatase and PTH, and no significant difference in final 25(OH)D levels 2

Target Levels and Treatment Goals

• Primary goal: Achieve serum 25(OH)D levels above 20 ng/mL (50 nmol/L) 1

• Optimal target: Aim for levels >50 nmol/L (20 ng/mL) to ensure adequate bone mineralization and prevent rickets 1

Maintenance Therapy

Age-Specific Maintenance Dosing

• Preterm infants: 200-400 IU/day 1

• Term infants (0-12 months): 400 IU/day from all sources 1

• Children and adolescents (1-18 years): 600 IU/day from all sources 1, 3

• These maintenance doses are endorsed by the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), the American Academy of Pediatrics, and the Institute of Medicine 1

Essential Co-Interventions

• Calcium supplementation: Provide 250-500 mg/day of elemental calcium during vitamin D treatment to support bone mineralization and prevent hypocalcemia, particularly in children with low ionized calcium or elevated PTH at baseline 1

• Dietary calcium: Ensure adequate dietary calcium intake during treatment, as vitamin D improves calcium absorption 1

Monitoring Protocol

Initial Monitoring

• Recheck 25(OH)D levels after 12 weeks of treatment to confirm normalization 1

• Baseline laboratory assessment: Consider evaluating serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels to assess for metabolic bone disease 1

Long-Term Monitoring

• Monitor 25(OH)D levels every 6-12 months once normalized, especially during winter months when sun exposure is limited 1

• For children on treatment: Monitor serum calcium and urinary calcium/creatinine ratio to detect asymptomatic hypercalcemia or hypercalciuria, which can occur transiently but typically resolves spontaneously 2

Formulation Selection

• Cholecalciferol (vitamin D3) is preferred over ergocalciferol (vitamin D2) due to higher bioefficacy for treating vitamin D deficiency 1

• Vitamin D3 maintains serum levels longer and has superior bioavailability compared to D2 1

Special Populations Requiring Modified Approaches

Children with Renal Insufficiency

• Children with chronic kidney disease may need higher or more frequent supplementation 1

• For CKD stages 3-5, optimal dosing is not well-established, but standard nutritional vitamin D replacement can be used 1

• Monitor calcium and phosphorus closely to avoid hypercalcemia 1

Children with Nephrotic Syndrome

• Monitor ionized calcium, 25(OH)D, and PTH levels closely due to massive urinary losses of vitamin D-binding protein 1

• Supplement with oral cholecalciferol or calcifediol plus calcium (250-500 mg/day) when levels are low or PTH is elevated 1

Children on Parenteral Nutrition

• Provide 200-1,000 IU daily (or 80-400 IU/kg/day) for preterm infants on parenteral nutrition 1

• Monitor periodically for vitamin D deficiency and provide additional supplementation for patients with 25(OH)D levels <50 nmol/L 1

• Consider oral supplementation for patients on partial parenteral nutrition and during weaning 1

Safety Considerations

Upper Tolerable Limits by Age

• 0-6 months: Maximum 1,000 IU/day 1

• 7-12 months: Maximum 1,500 IU/day 1

• 1-3 years: Maximum 2,500 IU/day 1

• 4-8 years: Maximum 3,000 IU/day 1

• 9-18 years: Maximum 4,000 IU/day 1

Monitoring for Adverse Effects

• Prolonged daily intake up to 10,000 IU appears safe, but serum concentrations >375 nmol/L are associated with acute hypercalcemia and hyperphosphatemia 1

• The 2024 trial found transient asymptomatic hypercalcemia in 51.4% of children on daily dosing and 34.3% on fortnightly dosing, which resolved spontaneously without intervention 2

• Hypercalciuria occurred in 5.7% of children on daily dosing but resolved on follow-up 2

Critical Pitfalls to Avoid

• Never use active vitamin D analogs (calcitriol, alfacalcidol, doxercalciferol, paricalcitol) to treat nutritional vitamin D deficiency, as they bypass normal regulatory mechanisms 1

• Ensure adherence to the treatment regimen, as inconsistent supplementation may lead to treatment failure 1

• Avoid excessive supplementation, as vitamin D toxicity can occur, though it's rare at recommended doses 1

• Assess for clinical manifestations of rickets at severe deficiency levels, as the child may already have skeletal changes that require evaluation 1

Clinical Manifestations to Assess

• At presentation with severe deficiency, evaluate for signs of rickets including bone pain, muscle weakness, skeletal deformities, and growth disturbances 4

• Vitamin D deficiency may present as hypocalcemia before bone demineralization, particularly during periods of increased growth velocity (infancy and adolescence), potentially causing seizures or tetany 4