Efficacy of low oral doses of iodized oil in the control of iodine deficiency in Zaire.

BACKGROUND: About one billion people worldwide are at risk for iodine deficiency. Despite existing programs of prophylaxis, the prevention of iodine deficiency is still a challenge throughout the developing world. We studied the efficacy of low doses of iodized oil in an area of severe iodine deficiency in Zaire.

METHODS: Seventy-five subjects with visible goiter were randomly assigned to receive a single oral dose of placebo or either 0.1 or 0.25 ml of iodized oil, corresponding to 0, 47, and 118 mg of iodine, respectively. The mean ages of the subjects in the three groups were 23, 22, and 22 years, respectively, and the ratios of males to females were 0.25, 0.32, and 0.19. Efficacy was assessed by evaluating goiter size and measuring urinary iodine and serum thyroid hormone concentrations for 12 months.

RESULTS: Goiter size decreased in most of the subjects who received either dose of iodized oil. Their urinary iodine concentrations were normal for six to nine months and their serum thyroxine and thyrotropin concentrations were nearly all normal throughout the study period. There were no side effects, even in subjects whose serum thyroxine concentrations had initially been low. In the placebo group, neither goiter size nor any of the biochemical values changed.

CONCLUSIONS: The oral administration of a single small dose of iodized oil is capable of correcting iodine deficiency for about a year. This method of supplementation is likely to be more effective, efficient, and acceptable than the administration of either intramuscular or large oral doses of iodized oil.