Dietary iodine intake level of adult population in coastal and inland areas of Zhejiang province / 中国地方病学杂志

ABSTRACT

Objective To evaluate the dietary iodine intake level of population in coastal and inland areas of Zhejiang province.Methods The cluster sampling method was applied to select Zhoushan,Ningbo and Taizhou cities from Zhejiang province as coastal areas,to select Jinhua,Quzhou and Lishui cities from Zhejiang province as inland areas,and two counties(districts) were randomly selected in each chosen city,three sub-districts(towns) were randomly selected in each chosen counties (districts),then one community (village) was randomly selected in each chosen sub-districts(towns).Adult residents aged greater than 18 were selected as investigation subjects,their dietary iodine intake in the past 24 hours was investigated,and the Food composition table” was inquired to get the data of dietary iodine intake.One hundred copies of residential edible salt samples and drinking water samples in each of the selected community (village) were collected to detect salt iodine and water iodine by direct titrimetric and spectrophotometric method,respectively.Results The mean of adult residents' dietary iodine intake in Zhejiang coastal area was 267.76 μg/d,which was less than that in inland area (429.05 μg/d,t =- 6.90,P ＜0.05),and the means of adult residents' dietary iodine intake from drinking water,laver and fish(5.75,69.72,5.61 μg/d,respectively) in coastal area were higher than those in inland areas(3.25,35.27,3.43 μg/d,respectively,t =21.73,3.92,4.08,all P ＜ 0.05),however,the means of adult residents' dietary iodine intake from salt,kelp and other food (166.81,3.04,16.82 μg/d,respectively) in coastal areas were less than those in inland areas (355.15,6.14,25.81 μg/d,respectively,t =- 8.76,- 5.49,- 18.56,all P ＜ 0.05).In coastal areas,the proportion which was less than estimated average requirement of iodine(EAR,120 μg/d) was 46.48％ (1029/2214),the ratio which was higher than the maximum tolerable intake of iodine(UL,1000 μg/d) was 3.34％ (74/2214),and the average contribution rate of dietary intake of iodine in salt was 62.30％(166.81/267.76).While in inland areas,the corresponding proportions were 7.61％ (171/2246),2.80％ (63/2246) and 82.78％ (355.15/429.05),respectively.Conclusions The dietary iodine intake in Zhejiang inland areas has reached the recommended nutrient intake levels of the Chinese Nutrition Society,but there is a certain degree of insufficient iodine intake in population of the coastal areas.