Adequacy of Dietary Iodine in Two Local Government Areas of Cross River State in Nigeria

Abstract

The Cross River State of Nigeria was in the goiter-endemic or goiter belt of Nigeria before the introduction of Universal Salt Iodization (USI) in 1996. After several years of availability and consumption of iodized salt in Nigeria, it has become necessary to revisit some of these previously goiter endemic areas so as to measure the effect of USI on the iodine nutriture, especially since goiter has not completely disappeared. This study was therefore initiated to assess the current iodine status of the population in relation to the USI programme in The state. Primary school children aged 8-12 years were recruited from ten schools in two Local Government Areas (LGA) in the Cross River State, using a simple random sampling technique. Casual, on the spot urine samples were collected from the children and analyzed for urinary iodine using the ammonium persulphate method. Salt samples were also collected from the households of the children in the study and analyzed for iodine content using titrimetric method. Four hundred school children participated in this study, 200 (50%) were males and 200 (50%) were females. One hundred and eighty-eight (47%) were 12 years old, while 95 (23.8%), were 11 years old, 80 (20%) were 10 years old, 32 (18%) were 9 years old and 5 (1.2%), were 8 years old. Median urinary iodine in these school children was 65µg/l. Ninety-nine (24.75%), had a median urinary iodine of 100-299 µg/l consistent with adequate iodine intake, while 136 (34.0%) had a median urinary iodine of 50-99 µg/l suggesting mild iodine deficiency. Only 92 (23%) of the children had a mean urinary iodine level less than 20 µg/l, which is consistent with severe iodine deficiency, while 73 (18.25%) of them were moderately deficient (20-49 µg/). However, the analysis of the table salt from the households showed that 74% of the households consumed salts with adequate iodine content of greater than 15ppm. In conclusion, the apparent contradiction observed between adequacy of table salt iodization and urinary iodine levels suggests the possible existence of factors such as improper use of table salt, poor handling by the retailers, high goitrogen content in the diets and cooking methods. These are areas of future research.