Related Experiment Videos
Normal values for random urinary calcium to creatinine ratios in infancy
J D Sargent1, T A Stukel, J Kresel
1Department of Pediatrics, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756.
Insights
Normal urinary calcium/creatinine ratio (UCa/Cr) is significantly higher in infants compared to older children and adults. Short-term infant formula supplementation with calcium and phosphorus showed minimal impact on infant UCa/Cr levels.
Area of Science:
- Pediatric Nephrology
- Clinical Chemistry
- Nutritional Science
Background:
- The urinary calcium/creatinine ratio (UCa/Cr) is a key indicator of calcium homeostasis.
- Establishing age-specific normal ranges for UCa/Cr is crucial for accurate clinical assessment in infants.
Purpose of the Study:
- To determine reference values for UCa/Cr in infants.
- To evaluate the effect of calcium and phosphorus supplementation in infant formula on UCa/Cr.
Main Methods:
- UCa/Cr was measured in urine samples from infants, children, and adults.
- A before-and-after trial assessed UCa/Cr changes during short-term infant formula supplementation with calcium glycerophosphate.
Main Results:
- UCa/Cr significantly decreases with age, with the highest values observed in infants (<7 months).
- Infant UCa/Cr geometric means were significantly higher than in older children and adults.
- Formula supplementation did not significantly alter mean UCa/Cr in infants.
Conclusions:
- Normal UCa/Cr values are substantially higher in infants than in older age groups.
- UCa/Cr demonstrates an age-related decline during early childhood.
- Calcium and phosphorus supplementation of infant formula has a negligible short-term effect on infant UCa/Cr.
Objective:
To determine normal values for the urinary calcium/creatinine ratio (UCa/Cr) in infants. To assess the impact of short-term supplementation of infant formula with calcium and phosphorus on UCa/Cr in a group of infants.
Design:
We determined UCa/Cr in randomly collected urine samples from a group of children and adults. Short-term supplementation of infant formula with calcium glycerophosphate was carried out in 21 infants, and UCa/Cr was monitored in a before-and-after trial.
Setting:
A pediatric clinic at an academic center (infants and adults), and a day-care center (older children).
Participants:
A total of 103 infants between 5 days and 7 months of age, 40 infants between 8 and 17 months of age, 41 children between 18 months and 6 years, and 31 adults.
Results:
The 95th percentiles for molar UCa/Cr for the different age groups were as follows: less than 7 months, 2.42 (0.86 mg/mg); 7 to 18 months, 1.69 (0.60 mg/mg); 19 months to 6 years, 1.18 (0.42 mg/mg); and adults, 0.61 (0.22 mg/mg). Regression analysis indicated a statistically significant decline in average UCa/Cr with age (R2 = 0.115, p < 0.0001 for log (UCa/Cr) vs log (age)). The geometric means for the two groups of infants were significantly greater than those of the older children and the adults (p < 0.05). Values for UCa/Cr in adults in our sample were comparable to those previously reported. We detected no significant changes in mean UCa/Cr during week-long periods of calcium supplementation of up to 1.8 gm of calcium and 1.39 gm of phosphorus per liter of formula.
Conclusion:
We conclude that normal values for UCa/Cr are much higher in infants than in older children and adults; UCa/Cr is age-related and declines gradually in the first several years of life, and short-term supplementation of infant formula with calcium glycerophosphate has minimal effect on UCa/Cr.