Iodine nutrition survey of children aged 8 to 10 in coastal and non-coastal areas of Rizhao city Shandong province / 中国地方病学杂志

ABSTRACT

Objective To investigate the iodine nutritional status of children aged 8 to 10 in both costal and non-costal areas of Rizhao city Shandong province,and provide a basis for scientific supplementation of iodine.Methods In 2009 and 2010,townships of Lanshan and Donggang were chosen as survey points which situated close to the coast,the counties of Wulian and Juxian that were more than 50 kilometers away from the coast were selected as controls.The iodine concentration of drinking water in every village and water supply point was determined.At the county level,5 to 9 towns were selected according to their sub-area positions of east,west,south,north and center,4 villages were selected in each chosen township,8 - 15 households were selected in each chosen village,edible salt from the households was collected; 5 primary schools were selected in each chosen township,60 students aged 8 - 10 were selected to take thyroid examination in each chosen school.Twenty copies of urine samples were collected from the 60 students to detect the iodine concentration.Iodine in drinking water was tested by cerous sulfate catalytic spectrophotometry,in iodized salt by direct titration,in urine by arsenic-cerium contact method,and thyroids were examined by palpation.Results Totally 3483 copies of drinking water samples,1164 copies of edible salt samples,and 476 copies of urine samples were tested,and a total of 1200 children aged 8 to 10 were investigated; and the ratio of water iodine frequency distribution ≤ 10 μg/L (in costal and non-costal area) accounted for 90.03％ ( 1011/1123 ) and 91.10％ (2150/2360),respectively,the medians of water iodine were 5.6 and 4.2 μg/L,respectively; the iodine medians of edible salt were 29.03 and 29.99 mg/kg,respectively; the consumption rates of qualified iodized salt were 96.77％ (569/588) and 97.05％ (559/576),respectively; total goiter rates were 1.17％(7/600) and 1.33％(8/600),respectively; the medians of urinary iodine were 144.05 and 159.15 μg/L,respectively; the percentages of urinary iodine that bellow 100 μg/L were 26.58％ (63/237) and 22.59％ (54/239),respectively; between 100 - 300 μg/L were 66.75％ (158/237) and 64.02％ (153/239),respectively;above 300μg/L were 6.75％ (16/237)and13.39％ (32/239),respectively.ConclusionsThe costal of Rizhao is an iodine deficient area.The current popularity of household's consumption of qualified iodized salt is suitable.The levels of iodine nutrition of children aged 8 to 10 is appropriate,which met the national standard of elimination of iodine deficiency disorders (IDD).There is no iodine excess.There are no significant differences in levels of iodine nutrition between costal and non-costal areas on the premise that the same iodized salt is supplied in both the areas,and there is no need to make differentiated supply of iodized salt.