RESUMO
OBJECTIVE: To investigate the relationship between iodine nutrition and growth/development in infants at the key period of brain development. METHODS: All women from pregnancy to the end of lactation and the weaning infants within 3 years in the Linxia Hui Autonomous Prefecture (Linxia Prefecture) were added iodized oil in 2006 - 2010. In 2006, 2010 one town was randomly selected from each of the five directions (east, south, west, north, central) of each county in Linxia Prefecture. One village was chosen from every town and 20 infants, 20 pregnant women and 20 lactating women were randomly selected in each town. Urinary iodine (UI) of the infants, pregnant and lactating women were determined. DQ value, height and weight of part of infants were measured. According to the above sampling plan, UI of pregnant women, lactating women and infants had been monitored every year after intervention. 0-3 infants were choosing to be control before intervention. RESULTS: UI of 1056 and 2989 0-3 infants were investigated before and after the iodine oil intervention. After the 'iodine oil' intervention, the median UI of infants increased from 107.3 µg/L to 139.6 - 190.7 µg/L, the percentage of UI level that lower than 50 µg/L, decreased from 23.9% to 6.7% - 12.9%. DQ value increased from 92.8 to 104.3, the percentage of normal height and above increased from 65.0% to 82.1% and the percentage of the normal weight and above, increased from 59.3% to 81.4%. The outcomes of DQ value, height and weight showed statistically significant differences, compared to the pre-intervention outcomes (P < 0.05). The median UI of pregnant and lactating women increased from 89.3 µg/L to 118.2 - 187.8 µg/L and from 84.9 µg/L to 135.2 - 187.5 µg/L respectively. CONCLUSION: Infant's growth and development were retarded when iodine deficiency existed at the key period of brain development. Intake of oral iodine oil at key period of brain development could provide adequate nutrition thus improve growth and development on infants.