Recurrence of mild iodine deficiency in
Tasmania
(November 2002)
The background of the study. Endemic
goiter was common before 1950 in Tasmania. Then, iodine intake was
increased by the distribution of potassium iodide tablets to schoolchildren,
and later by the addition of potassium iodate to bread and the use
of iodine-containing disinfectants in dairy cattle. The government
then mandated an upper limit for iodine content in milk, and the
addition of potassium iodate to bread ceased. By the 1990s, as dairy-farming
practices changed, some children had urinary iodine values <50
µg/L, indicative of moderate dietary iodine deficiency. This
study was undertaken to evaluate iodine nutrition in Tasmania 50
years after iodine supplementation was introduced.
How the study was done. The study
subjects were 225 children (99 girls, 126 boys; mean age, 11 years).
Morning urine samples were collected for the measurement of iodine,
and thyroid volume was measured by ultrasonography.
The results of the study. The median
urinary iodine excretion was 84 µg/L in the 225 children, and
20 percent had values of 50 µg/L or lower, indicative of moderate
iodine deficiency. The prevalence of thyroid enlargement in the
girls and boys was 21 percent and 22 percent, respectively, based
on age and body-surface area. There were no differences in thyroid
volume in the girls and boys, or among children living in different
areas of the state or having different socioeconomic status.
The conclusions of the study. The
values for urinary iodine excretion and the frequency of thyroid
enlargement indicate the recurrence of mild iodine deficiency in
Tasmania.
The original article. Guttikonda
K, Burgess JR, Hynes K, Boyages S, Byth K, Parameswaran V. Recurrent
iodine deficiency in Tasmania, Australia: a salutary lesson in sustainable
iodine prophylaxis and its monitoring. J Clin Endocrinol Metab 2002;87:2809-15.
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