Body Composition

Urine Metabolism Biomarkers Predict Preterm Infant Adiposity at Hospital Discharge.

TL;DR

Infant urinary amino acid and acylcarnitine concentrations varied by maternal diabetes and gestational age and were differentially related to postnatal adiposity in the preterm diabetes-exposed group, with factor 4 score (fatty acid and amino acid metabolites) associated with triceps skinfold thickness and mid arm circumference.

Key Findings

The study cohort consisted of 91 infants, of whom 25 were exposed to maternal diabetes and 68 were preterm.

  • 91 total infants enrolled
  • 25 (27%) were exposed to diabetes in pregnancy
  • 68 (75%) were preterm, with gestational age range of 30-36 weeks
  • Body composition assessments were completed at hospital discharge
  • Urine samples were collected in the first week of life for targeted metabolomics

Factor 4 score, representing fatty acid and amino acid metabolites, was associated with triceps skinfold thickness in the preterm-DM group.

  • β = 1.67 (95% CI: 0.62, 2.72) for association with triceps skinfold thickness
  • Association was identified specifically in the preterm-DM subgroup
  • Factor 4 was derived from factor analysis of urinary metabolites
  • Quantile regression was used to evaluate associations

Factor 4 score was associated with mid arm circumference in the preterm-DM group.

  • β = 1.59 (95% CI: 0.70, 2.49) for association with mid arm circumference
  • Association was identified specifically in the preterm-DM subgroup
  • Both triceps skinfold thickness and mid arm circumference were used as measures of adiposity

Urinary acylcarnitines C2, C3, and ornithine were decreased in the diabetes-exposed group.

  • Fold change < 0.67 for C2, C3, and ornithine in the DM group
  • p < 0.01 for these associations
  • These decreases were observed in urine samples from the first week of life

Urinary C0, C2, C3, C5, ornithine, proline, and lysine were increased in the preterm group compared to term infants.

  • Fold change > 2.7 for C0, C2, C3, C5, ornithine, proline, and lysine in the preterm group
  • p < 0.0001 for these associations
  • Both acylcarnitines and amino acids were elevated in preterm infants

Urinary metabolite signatures varied by both maternal diabetes status and gestational age and were differentially related to postnatal adiposity.

  • Differential relationships with adiposity were observed specifically in the preterm DM-exposed group
  • Unique signatures of urinary metabolites may reflect early metabolism changes in the developing infant
  • Both amino acids and acylcarnitines contributed to the differential metabolite patterns

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Citation

Buck C, McCollum S, Wang W, Lam T, Taylor S, Shabanova V. (2026). Urine Metabolism Biomarkers Predict Preterm Infant Adiposity at Hospital Discharge.. Molecular nutrition &amp; food research. https://doi.org/10.1002/mnfr.70431