Parathyroid hormone-ionized calcium dynamics over the first year of life

Abstract

AbstractIonized calcium (iCa) is believed to be the principle determinant of parathyroid hormone concentration (PTH). However, previous studies contained few infants.This ancillary study from our vitamin DNo significant correlations were observed between iCa and PTH at individual visits (p>0.2). After accounting for repeated measures, PTH decreased with increasing iCa (slope –5.25; 95% confidence intervals (CI) –8.78 to –1.73), decreased with increasing 25(OH)D (slope –0.006; 95% CI –0.009 to –0.002, and increased with later visits (6–12 months, p<0.001),We observed a weak negative relationship between iCa and PTH and an increase with age consistent with physiologic maturation.