Explain the Prevalence of Iodine Deficiency Disorders?

We can determine the prevalence of IDD by conducting population surveys. Most of the population surveys are based on clinical assessment of goitre and cretinism, which are the two classical features of iodine deficiency. Before we discuss the prevalence of IDD, let us find out the WHO criteria [or classification of goitre size. For clinical assessment of goitre, a standard technique based on palpation of thyroid is used through which goitre size can be assessed. Table gives the WHO criteria for classification of goitre size. The sum of grades 1 and 2 provides Total Goitre Rate (TGR). IDD is considered to be a public health problem, if the TGR is more than in 10% of the children aged 6-12 years in an area.

Table: Classification of goitre