The problem of goitre in Ceylon.

I . A survey of the incidence of goitre in Ceylon was carried out in the years 19479 and goitre was found to be endemic in the south-west sector of the Wet Zone of Ceylon. 2. In response to a request by the Ceylon Government to the World Health Organization for advice, Dr Dagmar Wilson in 1950 confirmed our earlier findings and as a short-term policy recommended the provision of iodine as KI tablets to the stress groups in the Wet Zone. This was initiated in August 1951. 3. A second survey was carried out in 1963 in nine of the villages in the Wet Zone that had been studied previously. 4. Statistical analysis showed that the incidence had significantly increased amongst the females in all nine villages and amongst the males in two villages. 5. A survey of the incidence amongst mothers attending antenatal clinics confirmed the existence of a strip of country where goitre was endemic. 6 . The critical level of iodine intake from drinking water below which goitre becomes endemic has been shown to be 10 ,ug/l. 7. The low iodine content of the water in the Wet Zone has been shown to be due to the persistent heavy rainfall, associated with high drainage into the ocean, by which the soil is leached. 8. The mean annual escape of water per square mile of a river basin (the yield factor) has been shown to be directly proportional to the intensity of endemic goitre in that basin. 9. The aetiological factors related to the problem of goitre are discussed. The prophylactic method failed as it was not sustained. 10. Iodization of kitchen salt is recommended for use by the general population. The amount of iodine added to the salt should not be great enough to produce any side-effects. Potassium iodate is suggested as the most suitable source of iodine for use in tropical regions with high humidity.