Interpretation of indicators of iodine deficiency disorders: recent experiences

Considerable progress has been made in the implementation of the universal salt iodization programmes in countries affected by iodine deficiency disorders (IDD). WHO/UNICEF/ICCIDD have jointly recommended outcome and process indicators to track the progress of IDD elimination programmes. Of the several indicators recommended in developing countries, goitre grading and urinary iodine are the most feasible to use as outcome indicators while iodine content of salt is the best as a process indicator. The WHO/UNICEF/ICCIDD recommendations provide separate cut-off points for these indicators to assess the severity of IDD. Recently, a nation-wide survey in Bhutan and another in New Delhi provided evidence that suggests that it is essential to view the results of all these indicators in totality rather than in isolation to make a proper assessment of the progress of the IDD elimination programmes. In view of these findings, we recommend (i) changing the goitre grading to only two grades from the current three, (ii) presenting urinary iodine values as median, cut-off points as well as the frequency distribution, and (iii) viewing the results of process and outcome indicators in totality to assess the severity of IDD.