Analysis of the monitoring results on iodine deficiency disorders in Liaoning Province in 2011

Abstract

Objective To understand the condition of iodine deficiency disorders,and the iodine nutritional status of population before adjustment of iodine level in edible salt in Liaoning Province.Methods Thirty countries （cites,districts） which were divided into coastal,inland,city,rural areas according to location and population characteristics were sampled by population probability sampling method in the whole province; one township （town,street office） was sampled from each country （city,district）; one village （neighborhood） and one school were chosen from each township（town,street office）.Forty children aged 8-10 were selected from each school to measure their thyroid volumes and household salt samples were collected to detect their iodine content; fourteen of those 40 children were selected to detect their urinary iodine content.In each village （neighborhood）,five drinking water samples were collected in the east,the west,the south,the north and the center positions.Two tap water samples were collected to detect their iodine content if the water supply was centralized.Around each school; three townships were selected,in each township,random urine samples were collected from 5 pregnant women and 5 lactating women to detect their iodine content.Thyroid volume was examined by ultrasound method; the salt iodine was tested by the method of direct titration; iodine content of urine and drinking water was tested by arsenic cerium catalytic spectrophotometry.Results Totally one thousand two hundred and nineteen children aged 8-10 were examined; twenty-nine children were diagnosed goiter,and the goiter rate was 2.4%（national standards：〈 5%）.One thousand two hundred and nineteen edible salt samples were tested,and the median salt iodine level was 30.1 mg/kg.The iodized salt coverage rate was 99.3%（1 211/1 219）,and the consumption rate of qualified iodized salt was 97.9%（1 194/1 219）.Four hundred and eighty urine samples were tested,and the median urinary iodine level was 189.0 μg/L（suitable content of salt iodine was 100-199 μg/L） ; urinary iodine 〈 20 μg/L accounted for 0.6%（3/480）.Ninety-nine drinking water samples were selected,and the average iodine content of the drinking water was （5.9 ± 5.7）μg/L.Four hundred and fifty-one urine samples of pregnant women and four hundred and fifty urine samples of lactating women were selected,and the median urinary iodine level of pregnant women and lactating women was 163.2,151.0 μg/L（suitable contents of urinary iodine in pregnant women and lactating women were 150-249 μg/L,〉 100 μg/L）.The median urinary iodine of pregnant women was 135.4 μg/L in coastal city,138.0 μg/L in coastal rural,168.0 μg/L in inland city,171.1 μg/L in inland rural.The difference of urinary iodine between coastal region and inland region was significant（H =14.287 6,P 〈 0.05）.Conclusions The iodine nutrition conditions of pregnant women,lactating women and children are adequate in Liaoning Province,but the iodine nutritional status is insufficient in pregnant women from the coastal areas. Key words: Thyroid; Urine; Salts; Iodine; Monitoring