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Intermittent high-dose vitamin D prophylaxis during infancy: effect on vitamin D metabolites, calcium, and phosphorus
T Markestad1, V Hesse, M Siebenhuner
1Department of Pediatrics, University of Bergen, Norway.
Insights
High-dose vitamin D prophylaxis in infants led to temporary vitamin D metabolite spikes. Despite this, some infants experienced excessive calcium levels, indicating potentially harmful dosing.
Area of Science:
- Pediatrics
- Endocrinology
- Nutritional Science
Background:
- Vitamin D prophylaxis is standard for infants.
- Intermittent high-dose ergocalciferol is a common regimen.
- Monitoring vitamin D metabolite and mineral levels is crucial.
Purpose of the Study:
- To assess serum vitamin D metabolites, calcium, and phosphorus levels in infants receiving high-dose vitamin D prophylaxis.
- To determine the impact of intermittent high-dose ergocalciferol on infant mineral homeostasis.
- To evaluate the safety and efficacy of the prophylactic dosing regimen.
Main Methods:
- Serum samples collected from infants before and 2 weeks after ergocalciferol doses.
- Analysis of vitamin D metabolites (25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, 25,26-dihydroxyvitamin D, 1,25-dihydroxyvitamin D).
- Measurement of serum calcium and phosphorus levels.
Main Results:
- 25-hydroxyvitamin D levels significantly increased post-dose but normalized before the next dose.
- 24,25- and 25,26-dihydroxyvitamin D levels correlated with 25-hydroxyvitamin D.
- 1,25-dihydroxyvitamin D levels remained largely within the normal range.
- 34% of infants showed hypercalcemia (elevated calcium levels) after dosing, indicating excessive vitamin D intake.
Conclusions:
- Intermittent high-dose vitamin D prophylaxis can lead to transient supra-normal vitamin D metabolite concentrations.
- The regimen may result in excessive calcium levels in a significant proportion of infants.
- Current dosing protocols may require adjustment to prevent hypercalcemia in infants.
Abstract:
In infants receiving intermittent high dose vitamin D prophylaxis (600,000 IU ergocalciferol per dose orally) every 3-5 mo, the serum concentrations of vitamin D metabolites, calcium (Ca), and phosphorus (P) were determined before and 2 wk after each dose. The 25-hydroxyvitamin D (OHD) concentrations increased to well above normal but the values returned to the normal range before each subsequent dose. The 24,25- and 25,26-dihydroxyvitamin D ([OH]2D) levels followed a pattern similar to that of 25-OHD, and both were closely related to the latter (r = 0.85, p less than 0.005, and r = 0.84, p less than 0.005, respectively). The 1,25-(OH)2D concentrations did not vary in a consistent pattern and remained largely within the normal range. All infants had normal Ca levels before the first dose but 14 infants (34%) later had one or both Ca values above the upper normal limit of 2.80 mmol/L (2.81-3.32 mmol/L), indicating that the vitamin D doses were excessive despite the lack of accumulative increases in serum vitamin D concentrations.