Thyroid ultrasound compared with World Health Organization 1960 and 1994 palpation criteria for determination of goiter prevalence in regions of mildand severe iodine deficiency

Objectives: In 1994, WHO/international Council for the Control of Iodine De ficiency Disorders recommended replacing the WHO 1960 four-grade goiter cla ssification with a simplified two-grade system. The effect of this change i n criteria on the estimation of goiter prevalence in field studies is uncle ar. In areas of mild iodine deficiency disorders (IDD) where goiters are sm all, ultrasound is preferable to palpation to estimate goiter prevalence. H owever, in areas of moderate to severe IDD, goiter screening by palpation m ay 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 Moro cco. Design: A cross-sectional study of 400 six- to 13-year-old children from tw o mountain villages (Ait M'hamed and Brikcha) in rural Morocco was carried out, Methods: Urinary iodine concentration (UI), whole blood TSH and serum thyro xine were measured. Thyroid size was graded by inspection and palpation by two examiners using both WHO 1960 and 1994 criteria. Thyroid volume was det ermined by ultrasound. Variation between examiners and examination methods was assessed. Sensitivity and specificity of the two classification systems compared with ultrasound were calculated. Results: Median UIs in Ait M'hamed and Brikcha were 183 and 24 mug/l respec tively. In Ait M'hamed. using 1960 and 1994 criteria, goiter prevalence was 21 and 26% respectively, compared with 13% by ultrasound, In Brikcha, with 1960 and 1994 criteria, goiter prevalence was 64 and 67% respectively comp ared with 64% by ultrasound, Agreement between observers was better with th e 1994 criteria than with the 1960 criteria in Ait M'hamed (kappa = 0.53 an d 0.47; respectively), while in Brikcha observer agreement was similar with the two systems (kappa = 0.67) Using either the 1994 or 1960 criteria, agr eement with ultrasound was only moderate in Ait M'hamed (kappa = 0.41-0.44) , but good in Brikcha (kappa = 0.55-0.64). Overall, compared with ultrasoun d, sensitivity increased 3-4% using 1994 criteria, while specificity decrea sed 4-5%, Conclusions: The WHO 1994 criteria are simpler to use than the 1960 criteri a and provide increased sensitivity with only a small reduction in specific ity. Agreement between observers is better with the 1994 criteria than with the 1960 criteria, particularly in areas of mild IDD. Like the 1960 criter ia, the 1994 criteria overestimate goiter prevalence in areas of mild IDD, compared with ultrasound. However, the 1994 palpation criteria provide an a ccurate estimate of goiter prevalence in areas of severe IDD, and may be an acceptable and affordable alternative to thyroid ultrasound in these areas .