Anthropometry-based 24-h urinary creatinine excretion reference for Chinese children

Area of Science:

• Pediatric Endocrinology
• Clinical Biochemistry
• Nutritional Science

Background:

• Accurate reference ranges for 24-hour urinary creatinine excretion are crucial for assessing somatic protein status in children.
• Existing reference ranges may not be applicable to diverse pediatric populations, necessitating region-specific data.
• The creatinine height index (CHI) is a valuable tool for evaluating protein metabolism, but requires reliable creatinine excretion data.

Purpose of the Study:

• To establish age- and sex-specific 24-hour urinary creatinine excretion reference ranges for healthy Chinese children.
• To derive reference values adjusted for anthropometric variables, particularly body weight and height.
• To provide data supporting the accurate calculation of the creatinine height index for nutritional assessment.

Main Methods:

• A cross-sectional survey involving 710 healthy Chinese children (377 boys, 333 girls) aged 8-13 years.
• Collection of twice-sampled 24-hour urine specimens and measurement of anthropometric variables.
• Statistical analysis to derive sex- and age-specific reference ranges and body weight-adjusted values for creatinine excretion.

Main Results:

• No significant difference in 24-hour urine volume between paired samples.
• Sex-specific, body-weight-adjusted creatinine excretion reference values: 15.3 mg/kg/day for boys and 14.3 mg/kg/day for girls.
• Significant differences in creatinine excretion between sexes, but not across age groups within the same sex. Derived height-based values for CHI calculation.

Conclusions:

• Established reliable 24-hour urinary creatinine excretion reference ranges for Chinese children.
• The derived sex-specific, body-weight-adjusted values are essential for accurate CHI calculation.
• These reference ranges facilitate the assessment of somatic protein status in pediatric populations.