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Urinary oxalate and glycolate excretion patterns in the first year of life: a longitudinal study
B Z Morgenstern1, D S Milliner, M E Murphy
1Department of Pediatrics, Mayo Clinic, Rochester, Minnesota 55905.
Insights
This study establishes normal urinary oxalate and glycolate excretion ranges for healthy infants. Formula-fed infants showed higher oxalate levels compared to breastfed infants.
Area of Science:
- Pediatric Nephrology
- Biochemistry
- Human Physiology
Background:
- Establishing reference ranges for urinary metabolites is crucial for diagnosing metabolic disorders in infants.
- Urinary oxalate and glycolate excretion patterns in healthy term infants are not well-defined.
- Longitudinal data is needed to understand developmental changes in these excretion levels.
Purpose of the Study:
- To prospectively determine the normal range of urinary oxalate and glycolate excretion in healthy term infants.
- To investigate the relationship between these excretion levels and infant age.
- To compare urinary oxalate levels between formula-fed and human milk-fed infants.
Main Methods:
- Prospective, longitudinal study of 30 healthy term infants.
- Collection of random urine samples at multiple time points from 2 days to 9 months of age.
- Measurement of urinary oxalate and glycolate using the oxalate oxidase and Olthuis assay methods, normalized to creatinine.
Main Results:
- Urinary oxalate and glycolate excretion values followed a log-normal distribution.
- Mean oxalate/creatinine ratios were 0.08 (oxalate oxidase) and 0.13 (Olthuis assay), with normalized ranges of 0.02-0.31 and 0.03-0.53, respectively.
- Mean glycolate/creatinine ratio was 0.07 (range 0.02-0.26), with no significant correlation with age. Formula-fed infants had significantly higher oxalate/creatinine ratios than human milk-fed infants.
Conclusions:
- This study provides essential reference ranges for urinary oxalate and glycolate in healthy term infants.
- Urinary oxalate excretion is influenced by feeding type, with higher levels observed in formula-fed infants.
- These findings contribute to the understanding of infant metabolism and can aid in the early detection of related disorders.
Abstract:
To determine the range of normal values, we studied urinary excretion of oxalate and glycolate prospectively and longitudinally in a cohort of 30 healthy term infants. Random urine samples were obtained at 2 days, 2 weeks, and 2, 4, 6, and 9 months of age. The results had a log-normal distribution. The mean oxalate/creatinine ratio, as determined by the oxalate oxidase method, was 0.08 (in milligrams of oxalate to milligrams of creatinine) with a normalized range of 0.02 to 0.31. The mean ratio when oxalates were measured by using the Olthuis assay was 0.13 (range 0.03 to 0.53). The mean glycolate/creatinine ratio was 0.07 (range 0.02 to 0.26). These values did not correlate with increasing age. The oxalate/creatinine ratios were higher in formula-fed infants than in those who were fed human milk (0.14 +/- 0.16 vs 0.08 +/- 0.04; p < 0.01).