What is the recommended vitamin D supplementation dosage for a 10-year-old male with vitamin D deficiency?

Vitamin D Supplementation for a 10-Year-Old with Deficiency (Level 18 ng/mL)

For a 10-year-old male with vitamin D deficiency (18 ng/mL), prescribe cholecalciferol (vitamin D3) 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy with 600-1,000 IU daily.

Understanding the Deficiency Severity

• A vitamin D level of 18 ng/mL represents true deficiency (defined as <20 ng/mL), requiring active treatment rather than simple supplementation 1
• This level places the child at risk for impaired bone mineralization and potential rickets, making prompt correction essential 2, 3
• The target level after treatment should be at least 30 ng/mL for optimal bone health and fracture prevention 1

Initial Loading Phase Protocol

The standard pediatric loading regimen mirrors adult dosing for documented deficiency:

• Administer 50,000 IU of vitamin D3 (cholecalciferol) once weekly for 8-12 weeks 1
• Vitamin D3 is strongly preferred over vitamin D2 (ergocalciferol) because it maintains serum levels longer and has superior bioavailability 1
• The 12-week duration is appropriate for this level of deficiency (<20 ng/mL) 1
• This cumulative dose of 600,000 IU over 12 weeks will typically raise levels by 40-70 ng/mL, bringing the child from 18 ng/mL to approximately 58-88 ng/mL 1

Maintenance Phase After Loading

After completing the 12-week loading phase:

• Transition to daily maintenance dosing of 600-1,000 IU vitamin D3 2
• The Institute of Medicine recommends 600 IU/day for children aged 1-18 years for skeletal health 2
• The Endocrine Society recommends 600-1,000 IU/day for children aged 1-18 years to prevent recurrence 2
• For children at higher risk (dark skin, limited sun exposure, obesity), use the higher end of this range (1,000 IU daily) 1, 4

Essential Co-Interventions

• Ensure adequate calcium intake of 1,000-1,200 mg daily from diet plus supplements if needed 1, 5
• Dietary calcium from food sources (dairy, fortified foods, leafy greens) is preferred over supplements 5
• If calcium supplements are needed, divide doses to no more than 600 mg at once for optimal absorption 1
• Do NOT start calcium supplements until after correcting the vitamin D deficiency, as this can worsen secondary hyperparathyroidism 5

Monitoring Protocol

• Recheck 25-hydroxyvitamin D levels 3 months after starting treatment (at completion of loading phase) 1
• Also check serum calcium and parathyroid hormone (PTH) at 3 months to assess for resolution of secondary hyperparathyroidism 5
• Once levels are stable and in target range (≥30 ng/mL), recheck annually 1
• If levels remain below 30 ng/mL despite treatment, verify compliance before increasing the dose 1

Administration Timing and Practical Considerations

• Administer vitamin D with the largest, fattiest meal of the day to maximize absorption 1
• Weekly dosing (50,000 IU) during the loading phase may improve compliance compared to daily high-dose regimens 1
• The rule of thumb: 1,000 IU daily increases serum 25(OH)D by approximately 10 ng/mL, though individual responses vary 1, 4

Safety Considerations

• The 50,000 IU weekly regimen for 12 weeks is well-established as safe in children, with no significant adverse events reported 1
• Daily doses up to 4,000 IU are generally safe for children aged 9-18 years 6
• The upper safety limit for serum 25(OH)D is 100 ng/mL, well above expected final levels with this regimen 1
• Avoid single ultra-high loading doses (>300,000 IU) as they may be inefficient or potentially harmful 1, 4

Critical Pitfalls to Avoid

• Do not use active vitamin D analogs (calcitriol, alfacalcidol) to treat nutritional vitamin D deficiency—these are reserved for specific conditions like advanced chronic kidney disease 1
• Do not rely on sun exposure for correction, as this increases skin cancer risk and is unreliable for achieving target levels 1
• Do not assume dietary sources alone will correct deficiency—very few foods naturally contain adequate vitamin D 3
• Do not start with only 400-600 IU daily maintenance dosing for documented deficiency, as this would take many months to normalize levels 1

Special Population Considerations

If the child has any of the following conditions, consider modified approaches:

• Malabsorption syndromes (inflammatory bowel disease, celiac disease): May require intramuscular vitamin D or substantially higher oral doses (4,000-5,000 IU daily) 1
• Obesity: May require higher maintenance doses due to sequestration in adipose tissue 1
• Dark skin pigmentation: Requires higher maintenance doses (800-1,000 IU daily) due to reduced cutaneous synthesis 1, 4
• Chronic kidney disease: Use standard nutritional vitamin D (cholecalciferol), not active analogs 1

Expected Outcomes

• Anti-fall efficacy begins at achieved levels of 24 ng/mL 1
• Anti-fracture efficacy requires achieved levels of at least 30 ng/mL 1
• With the recommended regimen, expect to achieve target levels (≥30 ng/mL) by 3 months 1
• Maintenance therapy prevents recurrence and supports ongoing bone development during this critical growth period 2, 7