Objective: To describe the epidemiology and analyze factors associated with iron deficiency anemia in a probabilistic sample of the Encuesta Nacional de Nutrición 1999 (ENN-99) [National Nutritional Survey 1999 (NNS-99)].
Material and methods: The sample included 8,111 children aged 1 to 12 years, and was nationally representative by rural and urban strata and by four geographical regions. Capillary hemoglobin was measured using a portable photometer (HemoCue). The analysis of the determining factors of anemia was performed by odds ratios derived from a logistic regression model and multiple regression models.
Results: The prevalence of anemia was 50% in infants < 2 years of age, with no significant differences between urban and rural strata or among regions. It varied between 14 and 22% in 6-11 year-old children and was higher in the South region and among the indigenous children. Dietary intake of iron was 50% of the recommended daily allowance in children < 2 years of age, but not in older children. Phytate ( approximately 500-800 mg/d) and tannin (approximately 19 mg/d) intakes were very high in children over 7 years of age. Hemoglobin was positively associated with nutritional status of children (p = 0.01), socioeconomic status (p range 0.05-0.001), duration of lactation in children under 2 years of age (p = 0.1), and iron and calcium intake (p = 0.02), but not with folic acid or vitamin B12 intake. Hemoglobin was negatively associated with maternal education (p = 0.01) in older children, but not in those under 2 years of age.
Conclusions: We present evidence of an alarming national epidemic of anemia, particularly marked in children 12 to 24 months of age. The control of anemia should be considered as an urgent national concern given its grave consequences on the physical and mental development of these children and on their long-term health. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.