Changes in the Prevalence of Micronutrient Deficiencies Among Under-2- and 6-Year-Old Children in two National Surveys in Iran

Micronutrients, such as vitamin A, vitamin D, iron, and zinc have several useful functions in the body and are necessary for normal growth and development, especially among children. Unfortunately, recent research has showed different levels of deficiency of these two vitamins among children.

This study aimed to compare the prevalence of micronutrient deficiencies, including vitamin A, vitamin D, iron, and zinc, among under-2- and 6-year-old children in Iran in two National Integrated Micronutrient Surveys (NIMS-I, NIMS-II).

In NIMS studies, sampling was done using a single-stage cluster sampling method. The country was divided into 11 study zones. Using simple random sampling, more than 4,400 individuals (about 400 samples in each zone) were included in each study (NIMS-I, NIMS-II). At least 4-mL venous blood samples were taken from all children and transferred to the central laboratory of Tehran University of Medical Sciences (TUMS) with special identification code for further analysis. Then, the levels of vitamin A, vitamin D, iron, and zinc were measured.

In NIMS-I, the prevalence of vitamin A deficiency among under-2-year-old children was 0.5%, which significantly increased to 18.3% in NIMS-II. Regarding vitamin D deficiency, the rate of deficiency was 3.7% in NIMS-I and 23.3% in NIMS-II, which was statistically significant. In none of the NIMS studies (I and II), vitamin A was measured in under-6-year-old children. Also, in the NIMS-I study, vitamin D was not measured among under-6-year-old children, and in NIMS-II study, the prevalence of vitamin D deficiency was 61.8%. Zinc deficiency among under-2-year-old children in both studies was nearly the same (19.1% vs. 19.4%); but in NIMS-II study, zinc deficiency among under-6-year-old children was 13.6%, which significantly decreased compared to the NIMS-I (31%). Iron deficiency status among under-2-year-old children significantly decreased from 37.8% in NIMS-I to 17.1% in NIMS-II. A significant reduction in iron deficiency status was also observed in the NIMS-II study compared to the NIMS-I in under-6-year-old children (9.9% in NIMS-II compared 18.2% in NIMS-I).

The increase in both vitamin A and vitamin D deficiency rates in NIMS study is alarming. Due to the special roles of these two vitamins in health, special considerations and effective actions are needed in this respect. Data from two national studies indicated a decrease in the prevalence of iron deficiency in both age groups, which could be due to the successful implementation of nutritional intervention programs in Iran, such as iron supplementation and iron fortification.