prevalence in regions of mild and severe iodine deficiency

Objectives: In 1994, WHO/International Council for the Control of Iodine Deficiency Disorders recommended replacing the WHO 1960 four-grade goiter classification with a simplified two-grade system. The effect of this change in criteria on the estimation of goiter prevalence in field studies is unclear. In areas of mild iodine deficiency disorders (IDD) where goiters are small, ultrasound is preferable to palpation to estimate goiter prevalence. However, in areas of moderate to severe IDD, goiter screening by palpation may be an acceptable alternative to thyroid ultrasound. To address these two issues, we compared WHO 1960 and 1994 criteria with thyroid ultrasound for determination of goiter prevalence in areas of mild and severe IDD in Morocco. Design: A cross-sectional study of 400 six- to 13-year-old children from two mountain villages (AõÈt M'hamed and Brikcha) in rural Morocco was carried out. Methods: Urinary iodine concentration (UI), whole blood TSH and serum thyroxine were measured. Thyroid size was graded by inspection and palpation by two examiners using both WHO 1960 and 1994 criteria. Thyroid volume was determined by ultrasound. Variation between examiners and examination methods was assessed. Sensitivity and specificity of the two classification system