Risk of hypervitaminosis D from prolonged feeding of high vitamin D premature infant formula.

Background: Most premature infant formulas marketed in Japan have high vitamin D content. Potential for vitamin D intoxication was assessed in premature infants with prolonged feeding of such a premature formula vitamin D content, 2700 IU/L.

Methods: Serum vitamin D, calcium and phosphorus, and urinary calcium, were measured in 12 very premature infants fed premature infant formula, regular formula (vitamin D content; 460 IU/L), and/or mother's milk.

Results: Concentrations of 25(OH)D in sera associated with sole feeding of premature infant formula (n = 40) were significantly higher than sera corresponding to regular formula or breast milk (n = 25; 175 versus 115 nmol/L, P <0.0001). No sample showed a serum 25(OH)D concentration below 25 nmol/L. Of 65 samples, 49 (75.4%) showed 25(OH)D concentrations exceeding 100 nmol/L, but serum calcium and phosphorus concentrations were normal. Unexpectedly, urinary calcium correlated negatively with serum 25(OH)D.

Conclusion: In prolonged feeding of premature infant formula with high vitamin D, it was concluded that it could cause a high blood concentration of vitamin D in premature infants, and also that in these infants urine calcium is not a reliable indicator of excessive vitamin D intake.