IODINE SUPPLEMENTATION - A COMPARISON OF ORAL AND INTRAMUSCULAR METHODS IN THE IMPROVEMENT OF THYROID-FUNCTION AND PROPHYLAXIS OF GOITER

The aim of this study was to determine which method of iodine suppleme ntation, oral or intramuscular, is most effective at reducing goitre a nd improving thyroid function over a 3-month period. Subjects were ran domly allocated at baseline by age and sex into 3 groups: a group give n a placebo capsule; a group given an oral supplement of Lipiodol (480 mg iodine); and a group given an intramuscular injection of Lipiodol. The field study was in Maskat, 1,700 meters above sea level and 250 k ilometers North-West of Dar Es Salaam, Tanzania. It is only accessible on foot being 9 hours walk from the nearest village, A total of 270 s chool children, aged 6 - 17 years were recruited into the study at bas eline and 203 subjects were available for the follow-up examination - a response rate of 75%. Personal details, anthropometric measurements and clinical data were collected at baseline. A 2 ml blood sample was taken and goitre grades recorded pre-supplementation and at the end of supplementation 3 months later. Thyroid hormone status was examined u sing RIA diagnostic kits (T3, T4) and a hsTSH 1-step immunoradiometric coated tube assay. TSH concentration increased significantly (p = 0.0 07) in the control group, Oral supplementation resulted in a decrease in goitre size and although T3 increased significantly (p = 0.024) the re was no significant change in either T4 or TSH concentrations. Intra muscular supplementation improved thyroid function, indicated by a sig nificant (p = 0.015) decrease in mean serum TSH concentration. Goitre sizes, however, increased significantly (p = 0.01) in this group. Oral iodine supplementation appears to provide a more rapid beneficial eff ect on goitre in the short term than intramuscular injection.