Evaluation of the effectiveness of salt iodization status in Tripura, north east India.

BACKGROUND & OBJECTIVES: Universal salt iodization programme was initiated during 1988-89 in the goitre endemic state of Tripura. However, no decline in goitre prevalence was found about a decade after the initiation of programme. The present work evaluates the quality of implementation of the salt iodization programme and the possible involvement of dietary goitrogens in the process. METHODS: The study areas were selected at random and in the selected areas only, school children were chosen purposively instead of the entire population. Iodine nutritional status was evaluated by measuring the urinary iodine excretion. The iodine content of salt collected from households was tested by iodometric titration, urinary iodine was measured by dry ashing method and thiocyanate by oxidising bromine and then developing colour by benzedine hydrochloride. RESULTS: Urinary iodine level was measured in 1,123 samples from 22 study areas. In 17 areas, the median urinary iodine values were > 100 micrograms/l indicating no biochemical iodine deficiency. However, the iodine intake of about 40 per cent of the studied population was below the cut-off level i.e., iodine level were < 100 micrograms/l. About two-thirds of salt samples were found to contain iodine less than the adequacy level of 15 ppm. Thiocyanate was present in the 1,032 urine samples studied, in different concentrations. INTERPRETATION & CONCLUSION: The people of region are exposed to inadequately iodized salt in spite of the salt iodization programme. Further, they are exposed to a thiocyanate load. This study suggests that monitoring of salt iodization programme is essential to ensure the recommended level of iodine (15 ppm) in at least 90 per cent salt samples. The goitrogenic/antithyroid potential of cyanogenic foods used in the region need to be ascertained to understand the nature of action on thyroid function.