[Prevalence of iron deficiency in children aged 7 months to 7 years in China].

OBJECTIVE: To collect epidemiological data of iron deficiency in Chinese children 7 months to 7 years of age, so more rational strategies of prevention and treatment against iron deficiency can be made.
METHODS: All the 31 provinces, municipalities and autonomous regions in China were first divided into 3 major regions based on geographic location socioeconomic developmental status. Among them, 15 provinces, municipalities and autonomous regions were randomly selected: 6 from the coastal regions, 5 from inland regions and 4 from remote regions. Then, 26 cities/counties were further selected from the 15 provinces, municipalities and autonomous regions. Ultimately, 9118 children aged 7 months to 7 years were selected as study subjects. Hemoglobin (Hb) was measured by cyanmethemoglobin assay, zinc protoporphorin by hemofluorescence assay and serum ferritin by radioimmunoassay.
RESULTS: The prevalence rates of iron depletion (ID) and iron deficiency anemia (IDA) were 32.5% and 7.8% respectively in children 7 months to 7 years in China. The prevalence rates were highest in infants (ID 44.7%, IDA 20.8%), followed by toddlers aged 1 - 3 years (ID 35.9%, IDA 7.8%) and preschoolers aged 4 to 7 years (ID 26.5%, IDA 3.5%), with statistically significant differences (P < 0.01). In countryside, the prevalence rates of ID were 35.8%, 31.0% and 27.6%, and the prevalence rates of IDA were 30.1%, 15.5% and 6.3% for children 7 to 12 months, 1 to 3 years and 4 to 7 years of age, respectively. While Hb measurements averaged (98.8 +/- 9.1) g/L, (98.2 +/- 10.5) g/L and (101.2 +/- 8.6) g/L respectively for the same age groups with IDA. In cities, the corresponding figures were 48.1%, 38.0% and 26.0% for ID, 16.8%, 4.4% and 1.9% for IDA, (101.0 +/- 6.8) g/L, (102.8 +/- 6.9) g/L and (104.2 +/- 4.4) g/L for average Hb measurements. There were statistically significant difference between the overall prevalence rate of iron deficiency in children living in rural areas and that of children in cities (42.0% versus 39.5%, P < 0.01). Obviously, there were significantly more urban children aged 6 months to 3 years suffering from latent iron deficiency than their rural counterparts, while there were more rural children with iron deficiency anemia. The average Hb measurements from each rural children age group with IDA were lower than that of their urban peers (P < 0.01).
CONCLUSIONS: ID was more prevalent than IDA in each age group in children, suggesting that latent iron deficiency was currently one of the major nutritional problems for Chinese children. The present study also showed that infants were still at higher risk for iron deficiency in spite of rapid socioeconomic development in the last two decades. Urban children were more likely to be inflicted by latent iron deficiency, while rural children were more prone to development of iron deficiency anemia. The susceptibility of rural children to development of iron deficiency anemia may be related to lower socioeconomic status of their families, poor hygienic conditions etc.