To the Editor: Tasmania has been recognised for many years as an area of endemic iodine deficiency.1 According to the World Health Organization, populations are considered iodine sufficient if population median urinary iodine (UI) levels exceed 100 μg/L, with less than 10% of the UI levels below 50 μg/L.2 Two random surveys (1998–99 and 2000–01) of Tasmanian school children aged 4–14 years suggest mild iodine deficiency. Median UI levels were 75 μg/L and 77 μg/L, with 13% and 21%, respectively, of the UI levels below 50 μg/L.3

In response to these findings, an iodine supplementation program was introduced in October 2001. Tasmanian bakeries were encouraged to switch to using iodised salt in place of regular salt. The program is voluntary, with participating bakeries asked to sign a memorandum of understanding. Industry advice suggests that bakeries that have signed the memorandum produce about 80% of the bread available for consumption in Tasmania.

The Tasmanian Iodine Monitoring Program commenced in July 2002. Its objectives are to determine the effect of iodine supplementation of bread on the general population and on high-risk groups, and to identify any negative health effects associated with the program.

Preliminary results from the monitoring are encouraging. Children were selected using a random cluster sampling approach. The sampling frame included all Grade 4 classes in all government, Catholic and independent schools in Tasmania. To date, 148 urine samples have been collected, with results from 124 available (test completion rate, 84%). The median UI level from the preliminary results is 97 μg/L (95% CI, 90–109 μg/L), with 10.5% below 50 μg/L. Ongoing monitoring will provide a more rigorous evaluation of the effects of the iodine supplementation program.

Early indications suggest the supplementation program may be achieving its goal of improving the iodine status of the Tasmanian population. The monitoring program will continue for the next 4 years, with regular surveys to detect any changes in the population’s iodine status. It will be challenging to retain the ongoing participation of the bread industry if, in the future, there is increased reliance on premixed and ready-to-bake products from outside Tasmania. Maintaining bread supplementation in Tasmania would then require cooperation from interstate suppliers to ensure iodine supplemention of these premixes and ready-to-bake products. Given that recent research has shown mild iodine deficiency in other parts of Australia and New Zealand, perhaps it is time for a bi-national solution to the problem.4,5