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

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.

A pilot survey of selenium status and its geospatial variation among children and women in three rural districts of Zimbabwe.

Introduction: Selenium (Se) deficiency is increasingly recognized as a public health problem in sub-Saharan Africa. Methods: The current cross-sectional study assessed the prevalence and geospatial patterns of Se deficiency among children aged 6-59 months (n = 741) and women of 15-49 years old (n = 831) selected by simple random sampling in rural Zimbabwe (Murewa, Shamva, and Mutasa districts). Venous blood samples were collected and stored according to World Health Organization guidelines. Plasma Se concentration was determined by inductively coupled plasma-mass spectrometry. Results: Median, Q1, and Q3 plasma Se concentrations were 61.2, 48.7, and 73.3 µg/L for women and 40.5, 31.3, and 49.5 µg/L for children, respectively. Low plasma Se concentrations (9.41 µg/L in children and 10.20 µg/L in women) indicative of severe Se deficiency risk was observed. Overall, 94.6% of children and 69.8% of women had sub-optimal Se status defined by plasma Se concentrations of <64.8 µg/L and <70 µg/L, respectively. Discussion: High and widespread Se deficiency among women and children in the three districts is of public health concern and might be prevalent in other rural districts in Zimbabwe. Geostatistical analysis by conditional kriging showed a high risk of Se deficiency and that the Se status in women and children in Murewa, Shamva, and Mutasa districts was driven by short-range variations of up to ⁓12 km. Selenium status was homogenous within each district. However, there was substantial inter-district variation, indicative of marked spatial patterns if the sampling area is scaled up. A nationwide survey that explores the extent and spatial distribution of Se deficiency is warranted.

Anemia in children aged 6-59 months was significantly associated with maternal anemia status in rural Zimbabwe.

Globally, anemia is a public health problem affecting mostly women of reproductive age (WRA, n = 452) and children aged 6-59 months (n = 452) from low- and lower-middle-income countries. This cross-sectional study assessed the prevalence and determinants of anemia in WRA and children aged 6-59 months in rural Zimbabwe. The venous blood sample was measured for hemoglobin utilizing a HemoCue machine. Anthropometric indices were assessed and classified based on World Health Organization standards. Socioeconomic characteristics were assessed. The median (±inter quartile range (IQR)) age of WRA was 29 ± 12 years and that for children was 29 ± 14 months. The prevalence of anemia was 29.6% and 17.9% in children and WRA, respectively, while the median (±IQR) hemoglobin levels were 13.4 ± 1.8 and 11.7 ± 1.5 g/dl among women and children, respectively. Multiple logistic regression analysis was used to assess determinants of anemia. Anemia in children was significantly associated with maternal anemia (odds ratio (OR) = 2.02; 95% CI 1.21-3.37; p = .007) and being a boy (OR = 0.63; 95% CI 0.41-0.95; p = .029), while anemia in WRA was significantly associated with the use of unimproved dug wells as a source of drinking water (OR = 0.36; 95% CI 0.20-0.66; p = .001) and lack of agricultural land ownership (OR = 0.51; 95% CI 0.31-0.85; p = .009). Anemia is a public health problem in the study setting. The positive association between maternal and child anemia reflects the possibility of cross-generational anemia. Therefore, interventions that focus on improving preconceptual and maternal nutritional status may help to reduce anemia in low-income settings.