TFRC and Iron deficiency anemia: Without accounting for the structure in the data (e.g., slight variations in demographic patterns within each region, or the nested sampling structure of individuals within households), there is a nearly 8-fold difference between the lowest and highest observed regional prevalence of vitamin B12, a 10-fold difference in vitamin A deficiency, a 4-fold difference in iron deficiency (based on transferrin receptor), and a ~ 2-fold difference in acute inflammation (CRP) and deficiencies of zinc and iron (based on ferritin; Figure 1).