Related Experiment Videos
Urinary calcium excretion in healthy children and adolescents
1Research Institute of Child Nutrition, D-44225 Dortmund, Germany. manz@fke.uni-dortmund.de
Insights
This study establishes normal urinary calcium excretion levels for healthy German children and adolescents. These findings aid in diagnosing hypercalciuria, noting puberty
Area of Science:
- Pediatric Nephrology
- Nutritional Science
- Clinical Chemistry
Background:
- Urinary calcium (Ca) excretion is a key indicator of calcium metabolism.
- Establishing reference ranges for pediatric populations is crucial for accurate diagnosis.
- The DONALD Study provides extensive data on children's health and nutrition.
Purpose of the Study:
- To determine and present normal urinary calcium excretion values stratified by age and sex in healthy children and adolescents.
- To analyze the impact of puberty on calciuria.
- To evaluate the diagnostic utility of random urine samples for hypercalciuria.
Main Methods:
- Analysis of 1,578 24-hour urine samples from 507 healthy children and adolescents (ages 2.8-18.4 years).
- Calculation of urinary calcium excretion per kilogram of body weight (mg/kg/day).
- Statistical analysis including log transformation and assessment of sensitivity, specificity, and predictive values for hypercalciuria.
Main Results:
- Calciuria (mg/kg/day) remained relatively constant, with a transient decrease during puberty, appearing later in boys than girls.
- Log transformation normalized the distribution of calciuria values.
- Hypercalciuria (>/=4 mg/kg/day) was observed in 8.6% of samples; >/=6 mg/kg/day in 1.5%.
Conclusions:
- This study provides age- and sex-specific reference values for urinary calcium excretion in healthy German children and adolescents.
- Pubertal changes in calciuria are sex-dependent.
- Elevated calciuria in a random urine sample is significant for diagnosing hypercalciuria.
Abstract:
Urinary calcium (Ca) excretion was determined in 1,578 24-h urine samples from 507 healthy children and adolescents (252 boys, 255 girls; 2.8-18.4 years) participating in the DONALD Study and is presented for 32 different age and sex groups. Calciuria values related to body weight (mg/kg per day) were relatively constant except for a transient decrease during puberty in all centiles, with a later onset in boys than girls. Distribution of calciuria (mg/kg per day) was best normalized by log transformation, with an almost constant standard deviation of the log-transformed values. Ca excretion was >/=4 mg/kg per day in 8.6% and >/=6 mg/kg per day in 1. 5% of the urine samples. Based on Ca excretion rates of 1,080 pairs of 24-h urine samples from 364 children and adolescents, sensitivity, specificity, and the predictive value for hypercalciuria (>/=4 mg/kg per day) in the next urine sample were calculated at three test levels classifying calciuria of the initial urine sample. In summary, this study presents normal values of urinary Ca excretion related to age and sex in a population of healthy German children and adolescents consuming a typical western-style diet. A high level of calciuria in a random urine sample is important in the diagnosis of hypercalciuria.