National Risk of Zinc Deficiency as Estimated by National Surveys

Abstract

Background: Information is needed on the national prevalence of zinc deficiency to guide program development and evaluation. Objective: To summarize results of national surveys that assessed plasma or serum zinc concentrations (PZC) and compare the prevalence of low PZC with other methods used to estimate countries’ risk of zinc deficiency. Methods: National surveys that included PZC were identified through Internet searches and personal contacts. A survey was eligible if a nationally representative sampling scheme was used, PZC was analyzed, and the survey was implemented in a low- or middle-income country. Twenty surveys were eligible; 19 countries assessed PZC in young children and 14 in women of reproductive age. Results: In 13 of the 19 surveys, the prevalence of low PZC in children was >20%. Only Afghanistan, Azerbaijan, Nigeria, the Republic of Maldives, Sri Lanka, and China found a low prevalence of inadequate PZC among children. Some of these conclusions may be due to the lower than recommended cutoff that was used. Similarly, in 13 of 14 surveys, the prevalence of low PZC in women was >20%. Estimates of percentage population with inadequate dietary zinc intake based on food balance sheets underestimate the risk of zinc deficiency. The national stunting prevalence seems to be a useful proxy, as both indicators categorized countries similarly into high versus low risk of zinc deficiency, with some exceptions. Conclusions: Results from 20 countries suggest that zinc deficiency is a public health concern in the majority of these countries and zinc intervention strategies should be considered.