Study of intelligence and psychomotor function in children aged 6 - 15 years and born pre and post universal salt iodization in Henan province in 2009

Objective Investigation and analysis of intelligence and psychomotor function in children born after implementingt universal salt iodization(USI). Methods Historical serious illness areas of water iodine below 10μg/L were selected as study sites, water iodine in 50 - 100 μg/L in the historical non-endemic areas were as control points in Henan, 2008. Cluster sampling was used to select children aged 6 - 15 years as observing subjects,IQ were measured with CRT- Man Test(CRT-C2). A "Tianjin Medical psychomotor test battery" (JPB) was carry out to test psychomotor function. Results In IDD regions 230 children were surveyed post-USI and 1284 children preUSI. The IQs post and pre USI were 99.3 and 99.9, respectively, and the proportion of IQ ≤69 were 2.17%(6/230) and 2.80%(36/1284), respectively. In non-IDD regions 650 children were surveyed post-USI and 2079children pre-USI. The IQs post and pre USI were 95.3 and 93.8, respectively, and the proportion of IQ ≤ 69 were 2.31%(15/650) and 3.37%(70/2079), respectively. In IDD regions, the abnormal rate of T scores and damage index post USI were 3.6%(2/56), 5.3%(3/56), respectively, significantly lower than pre USI [18.1%(29/160),18.1%(29/160), x2 = 7.54, 6.86, all P ＜ 0.01]. Conclusions USI could increase the IQs of children and decrease the positive rate of JPB, and significantly improve the quality of whole nation and persistently eliminating IDD. Key words: Iodides; Salts; Intelligence; Psychomotor function