Are Australian children iodine deficient? Results of the Australian National Iodine Nutrition Study.
OBJECTIVE
To document the population iodine nutritional status in Australian schoolchildren.


METHODS
Cross-sectional survey of schoolchildren aged 8-10 years, based on a one-stage random cluster sample drawn from all Year 4 school classes in government and non-government schools in the five mainland Australian states of New South Wales, Victoria, South Australia, Western Australia and Queensland. The study was conducted between July 2003 and December 2004.


METHODS
1709 students from 88 schools (881 boys and 828 girls), representing 85% of the estimated target number of students. The class participation rate was 65%.


METHODS
(i) Urinary iodine excretion (UIE) levels (compared with the criteria for the severity of iodine deficiency of the World Health Organization/International Council for the Control of Iodine Deficiency Disorders: iodine replete, UIE > or = 100 microg/L; mild iodine deficiency, UIE 50-99 microg/L; moderate iodine deficiency, UIE 20-49 microg/L; severe iodine deficiency, UIE < 20 microg/L); (ii) Thyroid volumes measured by ultrasound (compared with new international reference values).


RESULTS
Overall, children in mainland Australia are borderline iodine deficient, with a national median UIE of 104 microg/L. On a state basis, NSW and Victorian children are mildly iodine deficient, with median UIE levels of 89 microg/L and 73.5 microg/L, respectively. South Australian children are borderline iodine deficient, with a median UIE of 101 microg/L. Both Queensland and Western Australian children are iodine sufficient, with median UIE levels of 136.5 microg/L and 142.5 microg/L, respectively. Thyroid volumes in Australian schoolchildren are marginally increased compared with international normative data obtained from children living in iodine sufficient countries. There was no significant association between UIE and thyroid volume.


CONCLUSIONS
Our results confirm the existence of inadequate iodine intake in the Australian population, and we call for the urgent implementation of mandatory iodisation of all edible salt in Australia.
School of Public Health, University of Sydney, Edward Ford Building (A27), Sydney, NSW 2006, Australia. muli@health.usyd.edu.au
Mu
M
Li
Creswell J
CJ
Eastman
Kay V
KV
Waite
Gary
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Ma
Margaret R
MR
Zacharin
Duncan J
DJ
Topliss
Philip E
PE
Harding
John P
JP
Walsh
Lynley C
LC
Ward
Robin H
RH
Mortimer
Emily J
EJ
Mackenzie
Karen
K
Byth
Zelda
Z
Doyle
D000367:Age Factors; D002648:Child; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007455:Iodine / Q000172:deficiency* / Q000652:urine; D008297:Male; D009517:New South Wales; D009749:Nutrition Surveys; D011793:Queensland; D012016:Reference Values; D012737:Sex Factors; D013021:South Australia; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D014463:Ultrasonography; D014739:Victoria; D014904:Western Australia; D014944:World Health Organization
D007455:Iodine