Prevention and control of iodine deficiency: a review of a study on the effectiveness of oral iodized oil in Malawi.

Unfortunately there will always be groups of people who will not have access to iodized salt as a measure for iodine deficiency control. Iodized oil for oral use may be indispensable for them. The conclusions of a study in Malawi on the effectiveness of oral iodized are that the type of iodized oil, goitre, intestinal parasites, sex, adipose tissue, cassava consumption and seasonality are factors which influence the duration of effectiveness of this prophylaxis measure. The study in Malawi used urinary iodine concentration as a measure for iodine status and a hyperbolic function to describe the pattern of urinary iodine excretion after oral dosing. Cumulative frequency distributions of individually assessed durations of effectiveness very conveniently describe the prevalence rate of iodine deficiency after oral iodized oil administration. They are very useful for identifying factors which influence the effectiveness of oral iodized oil and may thus be a tool for optimizing iodized oil programmes.