Spatial Variation of Human Selenium in Ethiopia.

Selenium is an important nutrient for humans and livestock. Soil selenium concentration in the world is highly variable; deficiency and toxicity occur in populations living short distance apart. Knowledge of Se concentrations in humans and the environments, especially because the range for toxicity and deficiency is narrow, is important for effective intervention. Dietary data and serum samples were collected from children (n = 555) 69-78 months old from rural villages of the Amhara Region, Ethiopia. In addition, information on the socio-demography of households was collected. Serum Se was analyzed by inductively coupled plasma mass spectrometer. Almost all (90.3%) of participants reported eating grain, roots, or tubers 24 h preceding the survey followed by legumes, nuts, and seeds (64.6%). Consumption of animal source foods was very low (4.6%). Compared to children from the western part of the region, children from eastern Amhara had higher dietary diversity score (2.1 ± 0.9 vs 1.8 ± 0.7; p < 0.001).The median serum Se concentration was 70.6 µg/l (IQR 48.2, 96.6). Selenium inadequacy (serum Se < 70 µg/l) was detected in 49.1% of children. However, the distribution had an important geographical pattern across administrative zones. Children from the western part of the Amhara Region were highly deficient (up to 91.1% prevalence), while there was little or no Se deficiency in children from the eastern part of the region. Serum Se level exhibited an important spatial variation in the Amhara Region, Ethiopia. Further studies investigating contributing factors for the variation such as soil characteristics and Se concentration in staple crops are needed.