Phosphate Concentrations and Modifying Factors in Healthy Children From 12 to 24 Months of Age

J Clin Endocrinol Metab. 2021 Sep 27;106(10):2865-2875. doi: 10.1210/clinem/dgab495.

Abstract

Context: Phosphate homeostasis and its modifiers in early childhood are inadequately characterized.

Objective: To determine physiological plasma phosphate concentration and modifying factors in healthy infants at 12 to 24 months of age.

Design: This study included 525 healthy infants (53% girls), who participated in a randomized vitamin D intervention trial and received daily vitamin D3 supplementation of either 10 or 30 μg from age 2 weeks to 24 months. Biochemical parameters were measured at 12 and 24 months. Dietary phosphate intake was determined at 12 months.

Main outcome measures: Plasma phosphate concentrations at 12 and 24 months of age.

Results: Mean (SD) phosphate concentration decreased from 12 months (1.9 ± 0.15 mmol/L) to 24 months (1.6 ± 0.17 mmol/L) of age (P < 0.001 for repeated measurements). When adjusted by covariates, such as body size, creatinine, serum 25-hydroxyvitamin D, intact and C-terminal fibroblast growth factor 23, mean plasma phosphate was higher in boys than girls during follow-up (P = 0.019). Phosphate concentrations were similar in the vitamin D intervention groups (P > 0.472 for all). Plasma iron was associated positively with plasma phosphate at both time points (B, 0.006 and 0.005; 95% CI, 0.004-0.009 and 0.002-0.008; P < 0.001 at both time points, respectively). At 24 months of age, the main modifier of phosphate concentration was plasma creatinine (B, 0.007; 95% CI 0.003-0.011, P < 0.001).

Conclusion: Plasma phosphate concentration decreased from age 12 to 24 months. In infants and toddlers, the strongest plasma phosphate modifiers were sex, iron, and creatinine, whereas vitamin D supplementation did not modify phosphate concentrations.

Trial registration: ClinicalTrials.gov NCT01723852.

Keywords: clinical trial; hypophosphatemia; mineral homeostasis; phosphate; vitamin D.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Child, Preschool
  • Cholecalciferol / administration & dosage*
  • Creatinine / blood
  • Dietary Supplements*
  • Female
  • Healthy Volunteers
  • Humans
  • Infant
  • Infant, Newborn
  • Iron / blood
  • Male
  • Phosphates / blood*
  • Sex Factors
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamins / administration & dosage*

Substances

  • Phosphates
  • Vitamins
  • Vitamin D
  • Cholecalciferol
  • 25-hydroxyvitamin D
  • Creatinine
  • Iron

Associated data

  • ClinicalTrials.gov/NCT01723852