Calcium and Vitamin D Supplementation for Children with Genu Varum
For children with genu varum, the recommended daily supplementation is 400-600 IU of vitamin D and 1,000-1,300 mg of calcium, adjusted based on age. 1, 2
Vitamin D Supplementation
Recommended Daily Dosage
- Children 1-18 years should receive 400-600 IU of vitamin D daily for maintenance 2, 1
- Infants up to 12 months should receive 400 IU of vitamin D daily 2, 3
- Preterm infants may require higher doses, ranging from 200-1000 IU/day (or 80-400 IU/kg/day) 2
Treatment for Deficiency
- For children with diagnosed vitamin D deficiency, a treatment regimen of 2,000 IU daily for 12 weeks or 50,000 IU every other week for 12 weeks is recommended 1
- The goal is to achieve serum 25(OH)D levels above 50 nmol/L (20 ng/mL) 1, 4
- After the initial treatment phase, continue with maintenance therapy of 400-600 IU daily 1
Monitoring
- Measure serum 25-hydroxyvitamin D levels once per year in children with risk factors for deficiency 2
- During repletion phase, check serum calcium and phosphorus at 1 month after initiation or dose change, then every 3 months 2
- Once vitamin D levels are normalized, monitor yearly 2, 1
Calcium Supplementation
Recommended Daily Intake
- Children should receive 1,000-1,300 mg of elemental calcium daily, adjusted based on age 2, 1
- Dietary sources are preferred, but supplements can be used to reach target intake 2
- Calcium citrate is absorbed approximately 24% better than calcium carbonate, regardless of meal timing 5
Special Considerations for Genu Varum
- While vitamin D deficiency is not proven to be a direct cause of Blount disease (pathological genu varum), adequate vitamin D is essential for proper bone mineralization 6
- Vitamin D supplementation is crucial in preventing and treating rickets, which can present with genu varum deformity 4, 7
- Unilateral genu varum may require more aggressive investigation and treatment, as it is less likely to resolve spontaneously 7
Safety Considerations
Upper Limits
- Tolerable upper intake levels for vitamin D by age: 1,000 IU/day for infants 0-6 months, 1,500 IU/day for infants 7-12 months, 2,500 IU/day for children 1-3 years, 3,000 IU/day for children 4-8 years, and 4,000 IU/day for children 9-18 years 1
- Vitamin D toxicity is rare but can occur with excessive supplementation 2, 1
- Avoid excessive calcium supplementation, as high doses may increase risk of nephrocalcinosis in susceptible individuals 2
Clinical Approach
- Assess baseline calcium intake through dietary evaluation before recommending supplements 2
- Consider evaluating serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels to assess for metabolic bone disease 1
- For severe genu varum that doesn't improve with nutritional supplementation within 6 months, orthopedic consultation may be warranted 7
- Ensure adequate vitamin D status before orthopedic surgical interventions, as this may impact bone healing 7
Remember that while nutritional supplementation is important, severe or progressive genu varum may require additional orthopedic management beyond nutritional interventions, particularly if associated with Blount disease rather than simple nutritional deficiency 7, 6.