The Prevalence of Zinc Deficiency and its Correlation with Iron Status and Economical Living Area in 9-12-Year-Old Children

Objective: This study aimed firstly to assess zinc and iron status of 9 - 12-year- old children of Tehran and secondly to determine a cut-off for circulating biomarkers of iron status to identify children at increased risk of zinc deficiency. Research methods & procedures: In a cross-sectional study, demographic and anthropometric data from 505 boys and 467 girls aged 9 - 12 years from Tehran primary schools were obtained and their zinc and iron status was assessed. Results: The prevalence of zinc deficiency, anemia, and iron depletion was 12.4, 14.6, and 9.5%, respectively. Serum zinc con-centration was significantly lower in children with anemia than in their non-anemic peers (p < 0.05). There was no significant association between zinc and iron status and serum high sensitivity C-reactive protein. Zinc-deficient children, compared to those with normal serum zinc, had significantly shorter stature (139.7 (+/- 6.9) vs 141.3 (+/- 7.1) cm, CI: - 2.97 - -0.2, p = 0.029). Serum zinc concentration was the predictor of height in the children (p = 0.004, CI: 0.01 - 0.054). A logistic regression model showed an increased risk of low serum zinc and ferritin in children who resided in economically poor regions (OR = 1.65, p = 0.043; OR = 1.92, p = 0.016, respectively). Using ROC curve and Youden index, the optimal cut-off value for serum ferritin to indicate zinc deficiency was 14.9 mu g/L (sensitivity = 90%, specificity = 61%). Conclusions: Lowered zinc and iron status among the children in deprived regions is likely to be due to poor quality of diet. Moreover, children with serum ferritin lower than 14.9 mu g/L must be carefully assessed for concomitant zinc deficiency.