ENDEMIC GOITER AND HYPOTHYROIDISM IN ORANG ASLI AND MALAYS IN PENINSULAR MALAYSIA

The study was conducted to determine the prevalence of goiter and hypothyroidism in two groups of the population at various stages of social development and to determine its association with malnutrition and dietary intake. Aboriginal inhabitants (Orang Asli), a resettlement rural village (Betau Post), a traditional village in the jungle (Lanai Post) and a modern village settlement near Kuala Lumpur City (Bukit Lanjan) were selected. Three Malay villages with almost similar environments were selected for comparison. The study included house to house interviews, anthropometric, clinical and biochemical assessment of 1419 samples and estimation of iodine concentration in the drinking water of the areas studied. The World Health Organization criteria for classification of goiter were used. It was found that all Orang Asli settlements in rural areas were iodine deficient. The prevalence of goiter and hypothyroidism were higher among Orang Asli at all ages compared to Malays, and increased with remoteness of the areas (20-70% and 20- 30% respectively). Apart from iodine deficiency, a high intake of cassava and deficient intake of sea foods and protein diets were also significantly related with high prevalence of goiter. Among children, goiter was associated with the level of thyroid stimulating hormone (TSH) whereas among adults, body mass index (BM!), triiodothyronine and thyroxine levels were predictors for the presence of goiter. In conclusion, goiter and hypothyroidism were more common among Orang Asli compared to Malays, and were associated with rural location and poverty.