# Age‐related variations in prostaglandin E‐major urinary metabolite values in Japanese children

## TL;DR

This study establishes normal reference ranges for a urinary biomarker in healthy Japanese children, showing that younger children have higher values than older children and adults.

## Contribution

The study provides the first reference values for PGE-MUM in healthy children, highlighting age-related differences important for clinical interpretation.

## Key findings

- Young children (2–6 years) had higher PGE-MUM values (18.4–58.7 μg/g·Cr) compared to older children (7–14 years, 12.4–50.3 μg/g·Cr).
- PGE-MUM values decreased with age but showed no significant sex-related differences.
- Healthy children have higher PGE-MUM values than healthy adults, emphasizing the need for age-specific reference ranges.

## Abstract

Prostaglandin E‐major urinary metabolite (PGE‐MUM) is an emerging noninvasive biomarker used to evaluate clinical and endoscopic activity in patients with inflammatory bowel disease. Previous studies have shown that PGE‐MUM values correlate with colonic inflammation in pediatric ulcerative colitis; however, reference values for children without inflammation have not been defined yet. This study aimed to determine the normal reference values of PGE‐MUM in healthy pediatric subjects without inflammatory conditions.

Between December 2018 and January 2022, we prospectively enrolled 221 participants (cross‐sectional study, aged 0–15 years) who were undergoing growth hormone stimulation testing for diagnostic purposes and exhibited no symptoms of inflammation or elevated C‐reactive protein levels at a single pediatric center in Japan. PGE‐MUM values were measured using a chemiluminescent enzyme immunoassay and assessed for age‐ and sex‐related differences.

A total of 218 participants were included in the analysis. Based on age, the participants were classified as young children (2–6 years, n = 147) and older children (7–14 years, n = 66); the reference ranges for the two groups were identified as 18.4–58.7 μg/g·Cr and 12.4–50.3 μg/g·Cr, respectively. The PGE‐MUM values tended to decrease with increasing age; however, no significant sex‐related differences were observed (median 29.1 μg/g·Cr for boys versus 30.4 μg/g·Cr for girls).

Healthy pediatric subjects generally have higher PGE‐MUM values than healthy adults, with particularly elevated values in young children (2–6 years). These observations suggest that age‐related variability must be taken into account when using PGE‐MUM as a biomarker in young children with ulcerative colitis.