Urine Se concentration poorly predicts plasma Se concentration at sub-district scales in Zimbabwe, limiting its value as a biomarker of population Se status

Beaula Mutonhodza; Mavis P Dembedza; Edward J M Joy; Muneta G Manzeke-Kangara; Handrea Njovo; Tasiana K Nyadzayo; R Murray Lark; Alexander A Kalimbira; Elizabeth H Bailey; Martin R Broadley; Tonderayi M Matsungo; Prosper Chopera

doi:10.3389/fnut.2024.1288748

Urine Se concentration poorly predicts plasma Se concentration at sub-district scales in Zimbabwe, limiting its value as a biomarker of population Se status

Front Nutr. 2024 Feb 7:11:1288748. doi: 10.3389/fnut.2024.1288748. eCollection 2024.

Authors

Affiliations

¹ Department of Nutrition, Dietetics and Food Sciences, University of Zimbabwe, Harare, Zimbabwe.
² London School for Hygiene & Tropical Medicine, London, United Kingdom.
³ Rothamsted Research, West Common, Harpenden, United Kingdom.
⁴ National Nutrition Unit, Ministry of Health and Child Care of Zimbabwe, Harare, Zimbabwe.
⁵ School of Biosciences, University of Nottingham, Loughborough, United Kingdom.
⁶ Department of Human Nutrition and Health, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi.

Abstract

Introduction: The current study investigated the value of urine selenium (Se) concentration as a biomarker of population Se status in rural sub-Saharan Africa.

Method: Urine and plasma Se concentrations were measured among children aged 6-59 months (n = 608) and women of reproductive age (WRA, n = 781) living in rural Zimbabwe (Murehwa, Shamva, and Mutasa districts) and participating in a pilot national micronutrient survey. Selenium concentrations were measured by inductively coupled plasma-mass spectrometry (ICP-MS), and urine concentrations were corrected for hydration status.

Results: The median (Q1, Q3) urine Se concentrations were 8.4 μg/L (5.3, 13.5) and 10.5 μg/L (6.5, 15.2) in children and WRA, respectively. There was moderate evidence for a relationship between urine Se concentration and plasma Se concentration in children (p = 0.0236) and WRA (p = < 0.0001), but the relationship had poor predictive value. Using previously defined thresholds for optimal activity of iodothyronine deiodinase (IDI), there was an association between deficiency when indicated by plasma Se concentrations and urine Se concentrations among WRA, but not among children.

Discussion: Urine Se concentration poorly predicted plasma Se concentration at sub-district scales in Zimbabwe, limiting its value as a biomarker of population Se status in this context. Further research is warranted at wider spatial scales to determine the value of urine Se as a biomarker when there is greater heterogeneity in Se exposure.

Keywords: biomarkers; dietary selenium intake; estimated average requirement; iodothyronine deiodinase; micronutrient surveillance; selenium deficiency.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The authors acknowledge funding from the UK Research and Innovation (UKRI) Global Challenges Research Fund (GCRF) (grant number EP/T015667/1); Translating GeoNutrition: Reducing mineral micronutrient deficiencies (MMNDs) in Zimbabwe. The study was supported in part by Bill & Melinda Gates Foundation grant INV-009129 through the GeoNutrition project. Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the author’s accepted manuscript version that might arise from this submission. The funder had no role in the design, execution, analysis, or interpretation of the data.