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History of Iodine Deficiency in Schoolchildren in Tasmania, Australia
Citation
Hynes, KL and Blizzard, CL and Otahal, P and Venn, AJ and Seal, JA and Taylor, R and Dwyer, T and Burgess, JR, History of Iodine Deficiency in Schoolchildren in Tasmania, Australia, Comprehensive Handbook of Iodine: Nutritional, Biochemical, Pathological and Therapeutic Aspects, Academic Press, Victor R. Preedy, Gerard N. Burrow and Ronald Watson (ed), Oxford, pp. 1233-1249. ISBN 978-0-12-374135-6 (2009) [Research Book Chapter]
Abstract
Introduction: The island State of Tasmania, in Australia,
has long been recognized as an area of endemic iodine
deficiency. This chapter reviews the history of iodine deficiency,
supplementation and monitoring of school age
children in the state. The history of iodine nutrition from
1949, when the first survey and supplementation program
was undertaken, to the late 1980s when the population
was considered to be iodine sufficient is reviewed. Details
of the surveys conducted to confirm the re-emergence of
iodine deficiency following a period without regular monitoring
are presented. And the outcomes of a subsequent
voluntary program of bread fortification and a series of
post-fortification urinary iodine surveys are discussed. The
need for a sustainable form of iodine prophylaxis, preferably
universal salt iodization, is proposed. Recent Surveys of
Iodine in Tasmania: Six cross-sectional urinary iodine surveys
were conducted on Tasmanian schoolchildren. The first
two surveys (1998每1999 and 2000每2001) were conducted
to determine the status of urinary iodine levels in a representative
sample of children following more than a decade
without monitoring. In addition to urinary iodine measurement,
data were collected on the age, sex and school of
each participant. The school they attended was assigned
a residential category, a geographical classification and a
number of socioeconomic status (SES) scores. Parental education,
employment status, and occupation were recorded; a
food frequency questionnaire (FFQ) was completed; and a
range of questions about the frequency and recency of consumption
of iodine-containing foods was asked. Following
voluntary fortification of bread, a series of four postintervention
surveys were conducted in 2003, 2004, 2005
and 2007. Urinary iodine measurements were made and the
sex and school of each participant was recorded. As with the pre-intervention surveys, each school was assigned a residential
category, a geographical classification and three SES
scores. Summary of Survey Findings: Results for children aged
8每11 years are presented. For both the pre-intervention surveys
(1998每1999 and 2000每2001) the urinary iodine concentrations
(UIC), based on the World Health Organization
(WHO) definitions, were indicative of mild iodine deficiency.
The combined overall median UIC pre-intervention
was 77.5 城g/l. Seventy-five percent of the children had UIC
less than 100 城g/l. This was in excess of the WHO recommendation
that no more than 50% of a population-based
sample should have concentrations below 100 城g/l. Only
15.7% of the children, however, had UIC less than 50 城g/
l. This was within the WHO recommendation of no more
than 20% below this concentration. Following fortification,
the median UIC of schoolchildren examined in the four
post-intervention surveys improved significantly (108 城g/l,
P 肺 0.0001). Using the WHO definitions, the postintervention
UIC increased to a level indicative of optimal iodine
nutrition and reflecting adequate iodine intake. The percentage
of children with UIC less than 100 城g/l and 50 城g/l was
less than 50% and 20%, respectively, for all post-intervention
surveys. However, subgroups analysis revealed that while
boys were iodine sufficient (median UIC 123.0 城g/l), girls
bordered on insufficiency (median UIC 99.0 城g/l). In both
the pre- and post-intervention surveys there were no compelling
associations found between UIC and any of the SES
indicators. Children from private schools had similar median
UIC to those from public schools. All three school-based
ratings of SES were only weakly, but not statistically significantly,
associated with UIC. And UIC was not associated
with either maternal or paternal education, employment
status, or occupation. Categorization of schools into rural,
semirural and urban locations did not reveal any association
with UIC. Examination of geographical locations, which
had
Item Details
Item Type: | Research Book Chapter |
---|---|
Research Division: | Health Sciences |
Research Group: | Epidemiology |
Research Field: | Epidemiology not elsewhere classified |
Objective Division: | Health |
Objective Group: | Specific population health (excl. Indigenous health) |
Objective Field: | Neonatal and child health |
UTAS Author: | Hynes, KL (Dr Kristen Hynes) |
UTAS Author: | Blizzard, CL (Professor Leigh Blizzard) |
UTAS Author: | Otahal, P (Mr Petr Otahal) |
UTAS Author: | Venn, AJ (Professor Alison Venn) |
ID Code: | 59699 |
Year Published: | 2009 |
Deposited By: | Menzies Institute for Medical Research |
Deposited On: | 2009-12-16 |
Last Modified: | 2012-02-06 |
Downloads: | 0 |
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