Effect of early oral Calcium (Ca) supplementation on serum calcium levels and serum immunoreactive gastrin and calcitonin concentrations in premature infants

Abstract

In order to prevent early hypocalcemia in premature infants and to study its mechanisms, oral Ca supplementation (80mg/kg/24 h for 5 days) was given in 20 randomly selected infants and the evolution of serum Ca, magnesium (Mg), immunoreactive gastrin (iG) and calcitonin (iCT) concentrations were compared to the concentrations found in a control group of 20 infants matched for gestational age, Apgar score and birthweight. Prior to Ca supplementation (2-8 hours of age) serum Ca, Mg, iG and iCT levels were not different in the 2 groups. At 9 to 32 hours of age, serum Ca was higher in the supplemented group (mean ± SEM : 9 ± 0.1 mg/d1 vs 7.9 ± 0.2 in controls p < 0.05). Serum iCT levels were significantly lower in the supplemented group (p < 0.05). Serum Mg and iGT levels were similar in both groups. A negative correlation between serum Ca and serum iCT level was found in the control group (p < 0.01) but not in the Ca supplemented group. The incidence of hypocalcemia (<7.0 mg/d1) was 0 in the supplemented group and 4 in the controls. There was no clinical side effect of Ca supplementation. These data add further support for a role of calcitonin in the pathogenesis. of early neonatal hypocalcemia. They indicate that oral Ca can prevent the occurence of early neonatal hypocalcemia. They also suggest that this effect could be obtained by influence of oral Ca on serum iCT levels.