Intermittent oral administration of potassium iodide solution for the correction of iodine deficiency

Iodized salt and iodized oil are the main methods used to prevent iodine deficiency, but sometimes alternative approaches are needed. We tested the efficacy of various regimens for the intermittent administration of potassium iodide in Hwedza, Zimbabwe, an area of known severe iodine deficiency. We divided 304 schoolchildren aged 7-13 y into five equal groups that received iodine as a 10% solution of potassium iodide as follows: 8.7 mg every 2 wk (group A), 29.7 mg every month (group B), 148.2 mg every 3 mo (group C), 382 mg every 6 mo (group D), or 993 mg once (group E). The follow-up period was 13 mo. No adverse effects were encountered with any of these doses. After 6 mo, the median blood spot thyroglobulin concentration had decreased in all groups and had normalized in groups A and B to values found in iodine-sufficient populations. The number of children with elevated thyroid-stimulating hormone concentrations decreased in groups A-C, but the changes were not significant. Urine iodine concentration generally remained low in all groups but increased in group A. After 13 mo, mean thyroid volume measured by ultrasound had decreased in groups A and B to values comparable with those in iodine-sufficient areas, and was unchanged in the other groups. We conclude that oral potassium iodide is effective for the prophylaxis of iodine deficiency if given as a dose of 30 mg I monthly or 8 mg biweekly.