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Objective To analyze the examination results of external quality assessment (EQA),at all levels of iodine deficiency disorders (IDD) network laboratories in Ningxia Province and to further standardize and improve the laboratory,and to provide a reliable laboratory quality assurance for surveillance and control of IDD.Methods The examination results of EQA at all levels of IDD laboratories in Ningxia Province were statistically analyzed in accordance with the National Reference Laboratory (NRL) of IDD (2002-2011).Results Laboratory hardware equipment and technology at all levels met the testing requirements,and qualified rate of quality control increased year by year.Both of the response rate and qualification rate of urine iodine laboratories at provincial level were 100％ in the past decade.From 2005 on,the response rate of city laboratories had been 100％,and the qualification rate had been 100％ since 2007.The response rate and qualification rate of salt iodine laboratories at both the provincial level and the city level were 100％ in the past decade.The response rate of salt iodine laboratories at county level had been 100％ since 2004,and the qualification rate had been 100％ since 2009.Salt iodine and urinary iodine levels were fully qualified for the past three years at provincial,municipal and county levels.Conclusions All levels of IDD network laboratory in Ningxia Province runs good,EQA is fully qualified,and is able to provide a reliable laboratory quality assurance for surveillance and control of IDD.
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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.
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Objective To determine urinary iodine level among babies and infants aged 0-30 months in Ningxia, and to provide scientific evidence for strengthening iodine supplement or decreasing salt iodine level in special population. Methods One thousand four hundred and eighty-three babies and infants were selected randomly from 664 administrative villages of 22 counties (city or district) by two-stage sampling method. Urinary iodine was tested with the arsenic cerium catalysis spectrophotometric method and related influencing factors were analyzed. Results Urinary iodine median was 216.5 μg/L of the whole autonomous region, and the value that was lower than 100 μg/L, accounted for 19.1%(283/1483), 100 - 300 μg/L accounted for 49.3%(731/1483), higher than 300 μg/L, accounted for 31.6% (469/1483). Urinary iodine median was in 130.6 - 328.4 μg/L of all counties, which was higher than 100 μg/L. The urinary iodine median of men(223.2 μg/L) was slightly higher than that(210.2 μg/L) of female, no significant difference was observed(Z = - 1.76, P > 0.05). Urinary iodine level changed little when child was younger than one year old(Z = - 0.624, P > 0.05). Then the value dropped gradually after one year old(χ2 = 13.59, P < 0.05), decreased with age by month, and the proportion of the value smaller than 100 μg/L was increased gradually. Urinary iodine level(257.5 μg/L) of child whose mother had taken iodine oil pills was higher than that (221.2 μg/L) of child whose mother had significant difference was observed(Z = - 2.54, P < 0.05). The urinary iodine level (239.1 μg/L) of child who received breast feeding was higher than that (204.2 μg/L) of child without breast feeding among one year old and younger infants and babies, significant difference was observed (Z = - 2.74, P < 0.05). Conclusions Current iodine level in iodized salt is probably higher than suitable in Ningxia, and the value could be decreased. It is unnecessary to strengthen iodine supplement procedure in special population other than people in Xiji county.