Breast Milk Iodine Concentration Correlated with Urinary Iodine Concentration of Infants from Southern Ethiopia

Abstract

Breast milk from iodine‐sufficient mothers is considered an adequate source of iodine for the exclusively breastfed infant until the age of 6 months. A national policy requiring salt iodization was initiated in Ethiopia in 2011, but reports indicate high variability in salt iodine concentration (SIC) at the community level. Although the recommended household SIC should be 15‐40 ppm, salt from 102 rural households of lactating women in southern Ethiopia ranged from 0 to 39 ppm. Only about 20% of households had SIC >15 ppm. Mean ± SD age of mothers was 23 ± 3.9 y. Maternal BMI was 21.3 ± 2.5 and MUAC was 23.1 ± 1.9 cm. Goiter was observed in 75 of the mothers. Breast milk and urine samples were collected from these mothers and urine samples were collected from their 6 day old infants. Breast milk iodine (BMIC) and urinary iodine (UIC) were analyzed by inductively coupled plasma mass spectrometry (ICP‐MS). Median (Interquartile range) BMIC was 1551 (495, 2487) µg/L. Median maternal UIC was 106 (71, 160), but 47 had UIC below 100 µg/L. Median infant UIC was 212 (109, 348) µg/L. UIC of the mother correlated with BMIC (r=0.26, p< 0.007). BMIC and infant UIC were correlated (r=.34, p<0.0001) as were UIC of mother and infant (r=.63, p <0.0001). UIC of the mother and iodine of the household salt predicted 15% of the variation in BMIC while UIC of the mother and BMIC predicted 41% of the variability in UIC of the infant. Despite the fact that the study population was getting variable amounts of iodine from the recently implemented salt iodization program, BMIC at 6 days after delivery was high. (Supported by Néstle Foundation and Oklahoma Agricultural Experiment Station).