Abstract
Sonographic measurement of the thyroid gland volume is a safe and reliable method for epidemiologic studies in iodine deficiency disorders. Several factors such as age, sex and anthropometric characteristics are known to be the determinants of thyroid gland size but the most widely studied is the effect of insufficient iodine intake. Low iodine intake induces enlargement of the thyroid gland known as goitre. The assessment of urinary iodine concentration alone is not reliable as it can vary daily within individuals. Urinary iodine concentration in conjunction with sonographic thyroid gland measurements is a widely used method of thyroid gland assessment. Establishment of normative thyroid volume is essential for the assessment of iodine deficiency disorders, and studies have been conducted in several countries. These studies have shown that thyroid gland volumes are likely population-specific even in iodine-sufficient countries limiting the effectiveness of international reference ranges. Based on currently available data of sonographic thyroid gland volume measurements and how they vary across populations of school children, this review argues for the establishment of population-specific reference ranges in regions such as Australia, which are now considered iodine-sufficient.