PREVALENCE OF IODINE DEFICIENCY DISORDERS AND GOITER IN CHAD

A nationwide sample survey was conducted in Chad to establish the prev alence of iodine deficiency disorders (IDD). The country was stratifie d into the Sahel zone and the Sudan zone, the latter including the cit y of N'Djamena. The analysis followed a stratification whereby the cit y of N'Djamena was also separately analysed. A total of 1171 people be tween Io and 20 years of age were included in the survey. The overall weighted prevalence of goitre, evaluated by a clinical examination, wa s 63% In the Sudan zone the prevalence was 70%, in the Sahel zone 64% and for the capital, N'Djamena, 25%. There were significant difference s in the frequency of goitre between the three zones. Females-as estab lished in surveys from other areas and countries-had goitre significan tly more often. The prevalence of cretinism varied between 0 and 1.2%, and was highest in the Sahel zone. Amongst the sampled population of the Sudan zone, 33% had less than 20 mu g/l of urinary iodine, indicat ing severe iodine deficiency. In the Sahel zone and in N'Djamena the f igures reached 8 and 1%. There were high levels of thiocyanate anions in urine reaching medians between 21 and 27 mg/l in the geographical s tratas. This probably decreases the bio-availability of iodine. These data show that there is a high endemicity of goitre in Chad and provid e a basis for interventions as part of a national action plan against IDD, which will be adapted to the social, cultural and economic situat ion of the country and to available health services.