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 µg/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 µg/L must be carefully assessed for concomitant zinc deficiency.