ABSTRACT
Objective To study the iodine nutritional status of population living in Tibetan pastoral areas,in order to provide a scientific basis for prevention and control of iodine deficiency disorders.Methods Drinking water samples were collected to test iodine content in agricultural town(Kajiaman) and pastoral area(Zuogaiduoma town) of Hezuo in Gannan Tibetan autonomous prefecture.Thirty of child-bearing age,pregnant and breastfeeding women were selected,respectively,and 90 male adults aged 20-50 from these families(1 from each family) and 90 children aged 8-10 (30 people in each age group) from local schools were randomly sampled at the same time,and urinary iodine (UI) was measured randomly.Edible salt and main food samples were collected to test iodine content from the 10 families of the three types of women,respectively,and they were asked to recall its family intake of food species in the past 24 h excluding spices.The water iodine was determined using arseniccerium redox method (GB/T 5750.1-2006) ; UI with ammonium persulfate digestion-arsenic cerium catalytic spectrophotometric method (WS/T 107-2006) ; salt iodine used direct determination method(GB/T 13025.7-1999); and food iodine with alkali the gray arsenic cerium contact colorimetry.All these work were done in May,2011.Results The average of water iodine was (1.63 ± 0.14)μg/L in agricultural areas and (2.08 ±1.90)μg/Lin pastoral areas of the 10 water samples tested,respectively.The median urinary iodine(MUI) among women of pregnant,lactating and child-bearing age,male adults and children was 141.99,126.65,253.33,258.07,191.0μg/L,respectively,in agricultural areas and 137.26,97.36,126.16,159.48,285.07 μg/L,respectively,in pastoral areas.The difference of MUI in lactating,male adults and children between pastoral and agricultural areas was statistically significant.The proportion of UI ＜ 50 μg/L was less than 20％,and ＜ 100 μg/L was less than 50％ among all population except lactating woman and pregnant women in pastoral areas.The iodized salt coverage rate was 100％(30/30) in agricultural areas and 90％(27/30) in pastoral areas,and the salt iodine was (32.1 ± 7.8)mg/kg in agricultural areas and (32.3 ± 6.0)mg/kg in pastoral areas,respectively.The food structure in agricultural areas was mainly potato,naked oat fruit,cabbage and so on,the average dietary iodine content was 285.7 μg/kg,and in pastoral areas was mainly chow mein,wheat flour,ghee,yogurt,barley and so on,the average dietary iodine content was 51.1 μg/kg.Conclusions There is no iodine deficiency in general in the population in Tibetan areas with low water iodine.However,iodine nutrition of pregnant women can not be guaranteed.It is recommended that classified guidance measures be taken to ensure the sustainable elimination of iodine deficiency disorders in the Tibetan minority areas.