Are breast-fed infants and toddlers in New Zealand at risk of iodine deficiency?
OBJECTIVE
This study assessed the iodine status of New Zealand infants and toddlers and explored factors that might influence their iodine status.


METHODS
A community-based, cross-sectional survey of 6- to 24-mo-old children was conducted in three cities in the South Island of New Zealand. Iodine status was determined by a casual urine sample. Breast-feeding mothers were asked to provide a breast milk sample for iodine determination. Caregivers collected a 3-d weighed diet record from their children to investigate associations between dietary patterns and urinary iodine excretion.


RESULTS
The median urinary iodine concentration for the group (n = 230) was 67 microg/L (interquartile range 37-115) with 37% (95% confidence interval 30.5-43.4) of children having a urinary iodine concentration lower than 50 microg/L. When children were classified by current feeding method, those children who were currently formula-fed had a significantly higher median urinary iodine concentration (99 microg/L) than did children who were currently breast-fed (44 microg/L; P < 0.000). The mean iodine concentration in breast milk was 22 microg/L (n = 39). After multivariate analysis using estimates from 3-d diet records, only percentage of energy from infant formula was significantly associated with urinary iodine concentration (P = 0.005).


CONCLUSIONS
This study found mild iodine deficiency in a group of New Zealand infants and toddlers. Children who consumed infant formula, which is fortified with iodine, had better iodine status than did children who were currently breast-fed because breast milk contained low levels of iodine.
Skeaff
Sheila A
SA
Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
Ferguson
Elaine L
EL
McKenzie
Joanne E
JE
Valeix
Pierre
P
Gibson
Rosalind S
RS
Thomson
Christine D
CD
D001942:Breast Feeding / Q000009:adverse effects* / Q000706:statistics & numerical data*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D015930:Diet Records; D005260:Female; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology; D007455:Iodine / Q000172:deficiency* / Q000652:urine; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D009748:Nutrition Disorders / Q000453:epidemiology*; D009752:Nutritional Status / Q000502:physiology; D012044:Regression Analysis; D012307:Risk Factors; D011795:Surveys and Questionnaires
D007455:Iodine