ABSTRACT
Objective To investigate the iodine nutritional level of 5 special groups (newly married women,pregnant women, lactating women, babies and infants, and students) in Ningxia, and to provide the basis for formulating prevention and control strategies. Methods Clustering and random sampling method were used. In 2008 and 2009, in the 22 counties investigated, in every county with 9 townships or more, nine townships were randomly selected according to their sub-area positions of east, west, south, north and center; four villages were randomly selected in each chosen township, four people with special needs and 2 infants were randomly selected for urine samples collection in each chosen village. In every county with 9 or less townships, one township was randomly selected respectively in east, west, south, north and center sub-areas; four villages were randomly sampled in each chosen township, eight people with special needs and 3 infants' urine samples were randomly collected in each chosen village. In the 22 counties, one township was randomly selected respectively in east, west,south, north and center sub-areas, one village elementary school was randomly sampled in each chosen township,twenty students aged 8 - 10 were randomly selected to collect their urine samples in each school. The iodine concentration was determined by arsenic-cerium contact method. Results A total of 6894 copied of urine samples from newly married women, pregnant women, lactating women, babies and infants, and students were examined, the urinary iodine medians were 209.3, 187.4, 184.0, 216.5, 216.3 μg/L, respectively. From low to high in the order was lactating women, pregnant women, newly married women, students, babies and infants. The level of urinary iodine of babies and infants, pregnant women and lactating women were appropriate, the one of newly married women and students were higher than appropriate. The proportion of less than 100 μg/L of urinary iodine of the 5 kinds special groups were 11.1% (53/475), 35.4% (308/871), 35.4% (659/1863), 19.1% (283/1483), 8.4%(185/2202), respectively, while the urinary iodine of the pregnant women and lactating women were relatively high. The urinary iodine medians of the 5 special groups were also very different among counties. Conclusions The urinary iodine of the 5 special groups in Ningxia presents obvious differences between populations and regions.Current iodized salt is sufficient to ensure iodine nutrition needs for the 5 special groups. But married women and students have higher levels of iodine nutrition, indicating that the salt iodine concentration of Ningxia residents have cut space, full consideration of the 5 special groups and regional differences should be taken.