An investigation of iodine nutritional status in vulnerable populations and iodine content in edible salt in Xiamen City of Fujian Province in 2011

Objective To assess the iodine nutritional status of some vulnerable populations and iodine content in edible salt in Xiamen City for providing basic evidence for policy-making against iodine deficiency disorders(IDD).Methods This study had been initialized from April to November in 2011 and random sampling was applied in accordance with the national program.In each district 9 townships(streets) were randomly selected according to their sub-area positions in north,south,east,west and center of the district; 4 villages(neighborhood) were randomly sampled in each chosen township(street) ; 8 households were randomly selected in each chosen village (neighborhood).In every district with 9 or less township(If there were less than five towns in the district,all towns had been selected),1 township (street) was randomly selected,respectively,in north,south,east,west and center sub-areas of the district; 4 villages(neighborhood) were randomly sampled in each chosen township(street) ; 15 households were randomly selected in each chosen village(neighborhood).Edible salt samples from these households were collected.According to north,south,east,west and center position in each district,a primary school was selected in each town(if there were less than five towns in the district,all towns had been selected).Forty subjects aged from 8 to 10 in each school were randomly selected to perform thyroid examination and 20 of them were selected to collect urine samples for determination of urinary iodine.Urine samples were collected from at least 60 pregnant women and 60 lactating women at least in Siming,Haicang and Xiangan districts to determine urinary iodine.The goiter situation was examined by palpation.As for laboratory assay,salt-iodine and urine-iodine were determined by applying direct titration and arsenic cerium catalytic spectrophotometry,respectively.Results The coverage rate of iodized salt was 98.1％(1624/1656),the rate of edible qualified iodinated salt was 97.1％(1608/1656),and the rate of noniodized salt was 1.9％ (32/1656).The adjusted goiter rate of children aged 8-10 was 1.13％ (14/1239),the median of urinary iodine was 203.99 μg/L,and the proportion of urine-iodine level ＜ 50 μg/L was 5.4％ (35/647).The median of urinary iodine of the pregnant women was 152.4 μg/L,and the proportion of urine-iodine level ＜ 150 μg/L was 45.2％(28/62).The median of urinary iodine of the lactating women was 139.4 μg/L,and the proportion of urine-iodine level ＜ 100 μg/L was 30.0％ (18/60).Conclusions All the indicators in Xiamen City have been identified as appropriate in accordance with the national standard to eliminate IDD in 2011.The levels of iodine nutrition in some pregnant women and lactating women are still lower than normal range,and we must paid more attention to them.Routine monitoring of iodine nutritional status should be carried out among pregnant women and lactating women,and knowledge on iodine nutrition should be well propagandized to prevent and control the occurrence of IDD. Key words: Iodine ; Deficiency diseases; Urine; Salts ; Vulnerable population