Investigation of iodine nutrition among different populations after adjusting the salt iodine concentration in Dali City of Yunnan Province / 中华地方病学杂志

ABSTRACT

Objective After implementation of new standard iodized salt,to comprehensively assess the iodine nutrition levels of different populations in Dali City of Yunnan Province.Methods From 2012 to 2015,in Dali City,there were 5 districts divided into east,west,south,north and middle,each district selected 1 township (town),and each township (town) selected 4 administrative villages,15 households for edible salt in each administrative village were sampled,and the salt iodine content was measured by "General Test Method in Salt Industry Determination of Iodine" (GB/T 13025.7-2012).In 2014,in the five districts of east,west,south,north and middle of Dali City,one township (town) was selected,and 20 pregnant women in the early,middle and late stages,respectively,20 lactating women,20 ordinary healthy adults and 20 children aged 0 to 4 were selected from each township (town);one primary school in each township (town) was selected in each district,and 40 students aged 8-10 years old were selected from each primary school as the survey objects.The urine samples of the survey objects were collected,and the urinary iodine content was measured by "Method for Determination of Iodine in Urine by As3+-Ce4+ Catalytic Spectrophotometry" (WS/T 107-2006).In 2015,in each administrative village of Dali,a water source with the largest number of drinking people was investigated,and water iodine was detected by the "Method of Water Iodine Detection Suitable for Iodine Deficiency and High Iodine Areas".Through questionnaires,the sources of iodine supplementation for pregnant and lactating women were investigated.Results The qualified iodized salt consumption rate of residents was higher than 90％ per year from 2012 to 2015,and median of salt iodine decreased from 29.38 mg/kg (2012) to 24.96 mg/kg (2015).The medians of urinary iodine in different populations were 136.85 μg/L for pregnant women (n =356),102.63 μg/L for lactating women (n =111),164.03 μg/L for adults (n =163),209.61 μg/L for 8-10 years old children (n =200),157.27 μg/L for children aged 0-＜ 2 years old (n =57),and 134.08 μg/L for 2-4 years old children (n =50).The median of iodine content of drinking water (n =142) in Dali was 0.62 μg/L,the range of iodine content was 0.00-9.92 μg/L.The average intake frequencies of iodine-rich seaweed for pregment women and lacting women were 0.99,1.07 time/month,respectively,only 1.99％ (9/453) of the population supplemented iodine through multivitamin and minerals tablets.Conclusions After reduction of salt iodine content,the iodine nutrition of populations in Dali City (a low water iodine region) is generally at an appropriate level.Maintaining a higher level of qualified iodized salt consumption rate,strengthening the monitoring of different populations and promotion of healthy behaviors are key steps in prevention and control of the disease in the future.