Urine Se concentration poorly predicts plasma Se concentration at sub-district scales in Zimbabwe, limiting its value...

Area of Science:

• Nutritional biochemistry
• Biomarker research
• Public health nutrition

Background:

• Selenium (Se) is an essential trace element crucial for human health.
• Assessing population selenium status is vital for public health interventions, especially in regions like sub-Saharan Africa.
• Biomarkers such as urine and plasma selenium concentrations are commonly used to evaluate selenium status.

Purpose of the Study:

• To investigate the utility of urine selenium concentration as a biomarker for assessing population selenium status in rural sub-Saharan Africa.
• To evaluate the relationship between urine and plasma selenium concentrations in children and women of reproductive age in Zimbabwe.
• To determine if urine selenium can predict selenium status based on established thresholds for iodothyronine deiodinase activity.

Main Methods:

• Measured urine and plasma selenium concentrations in 608 children (6-59 months) and 781 women of reproductive age (WRA) in rural Zimbabwe.
• Utilized inductively coupled plasma-mass spectrometry (ICP-MS) for selenium analysis.
• Corrected urine selenium concentrations for hydration status and analyzed relationships with plasma selenium and indicators of selenium deficiency.

Main Results:

• Median urine selenium concentrations were 8.4 μg/L in children and 10.5 μg/L in WRA.
• A moderate correlation was found between urine and plasma selenium in both groups, but with poor predictive value.
• An association between selenium deficiency (based on plasma levels) and urine selenium was observed in WRA, but not in children.

Conclusions:

• Urine selenium concentration demonstrated poor predictive value for plasma selenium at sub-district scales in Zimbabwe.
• The findings limit the utility of urine selenium as a biomarker for population selenium status in this specific context.
• Further research is recommended at broader spatial scales to explore the biomarker's value under conditions of greater selenium exposure variability.