Endemic goitre in Sarawak, Malaysia: I. Somatic growth and aetiology.

A comparative epidemiological and anthropometric survey was conducted among Ibans, the largest indigenous ethnic group in Sarawak, in three regions where the endemicity of goitre exhibited marked differences , to assess the effect of endemic goitre on somatic growth. In the Ai river region the prevalence of goitre was 99.5%; 35% having grade 3 goitres, 55% grade 2 goitres and 9.5% grade 1 goitres. At Rubu the prevalence of endemic goitre was 74%; 3% having grade 3 goitre, 16% grade 2 goitre and 55% grade 1 goitre. In the Bajong region relatively few people were detected with goitre and most of these had migrated from other regions. Neurological cretinism was estimated at 3.6% in the severely goitrous Ai river population but was not detected in the other regions. Anthropometric data obtained from the three adult populations did not reveal any statistically significant differences in the following parameters: weight, height, weight/height ratio, height/sitting height ratios, head circumference, scapular skinfold thickness and left mid arm muscle circumference. The haemoglobin, serum total protein and serum albumin concentrations were similar in the three populations. It is concluded that endemic goitre occurs with a frequency of close to 100% in certain Iban populations which represents one of the highest incidences of endemic goitre in the world. Neurological cretinism is common in this population. Our observations suggest that body proportions and somatic growth do not vary among similar ethnic populations exhibiting greatly different endemicity of goitre. Although no iodine balance studies were performed, assessment of diets suggested that iodine deficiency is a significant contributory factor in the development of endemic goitre in Sarawak. Urgent attention to iodine supplementation is indicated to prevent the development of endemic goitre and neurological cretinism.