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Urinary selenium excretion in infancy: comparison between term and preterm infants
H Tsukahara1, Y Deguchi, M Hiraoka
1Department of Pediatrics, Fukui Medical School, Japan.
Insights
Urinary selenium (Se) levels peak at one month in term infants but decrease in preterm infants. Urinary Se reflects body stores, not renal function, serving as a marker for infant Se status.
Area of Science:
- Pediatric Nutrition
- Trace Element Metabolism
- Renal Physiology
Background:
- Selenium (Se) is vital for glutathione peroxidase activity.
- Understanding infant selenium status is crucial for development.
- Urinary Se excretion is a potential noninvasive marker.
Purpose of the Study:
- To evaluate urinary Se excretion in infants.
- To examine the relationship between urinary Se and renal function.
- To establish urinary Se as a marker for Se status in infants.
Main Methods:
- Analyzed daytime spot urine samples from 80 infants (term and preterm) aged 1 week to 7 months.
- Measured urinary Se concentration using fluorometry.
- Assessed renal tubular function via beta 2-microglobulin levels using radioimmunoassay.
Main Results:
- Urinary Se peaked at 1 month in term infants.
- Preterm infants showed higher urinary Se at 1 week but lower levels subsequently.
- No significant correlation found between urinary Se and beta 2-microglobulin in any group.
Conclusions:
- Renal Se excretion likely indicates body Se stores, independent of renal function in infants.
- Urinary Se is a valuable, noninvasive tool for diagnosing and monitoring Se deficiency in infants.
Abstract:
We evaluated the urinary excretion of selenium (Se), an essential component of glutathione peroxidase, in infants aged 1 week and 1, 4, and 7 months and examined the relationship between urinary Se and renal function. Daytime spot urine samples from a total of 80 infants were analyzed. The Se concentration in urine was measured by fluorometry, while the beta 2-microglobulin content, an index of renal tubular function, was determined by radioimmunoassay. In healthy term infants, the urinary Se excretion showed a peak level at 1 month of age. In contrast, the urinary Se concentration rapidly decreased in preterm infants from 1 week to 7 months postnatally. The level at 1 week in preterm infants was significantly higher than that in term infants, although the mean levels at 1, 4, and 7 months were lower in preterm infants. The level of urinary Se did not correlate significantly with the beta 2-micro-globulin concentration, either in term or preterm infants at any age investigated. Our results suggest that the renal excretion of Se probably reflects the body stores of Se and is not related directly to the renal function in infants. Urinary Se, a noninvasive marker of the Se status, may be used for diagnosis and follow-up of Se deficiency in infants.