摘要目的 评价学龄儿童尿碘水平的稳定性以及儿童尿碘水平对其父母尿碘水平的代表性,为碘缺乏病的监测与控制提供科学依据.方法 在哈尔滨市区内和周边农村的小学校中,利用整群抽样方法,抽取8～ 10岁学龄儿童作为调查对象,于2011年9月份连续收集3d儿童的日间随意1次尿样,采用过硫酸铵消化-砷铈催化分光光度法检测尿碘.同时,进行富碘食品摄入情况问卷调查,内容主要涉及学龄儿童是否在采尿期间以及采尿前3d食用北方最常见的富碘食品,包括海带、紫菜、海苔等海产品,排除富碘食品摄入对尿碘稳定性的干扰,评价学龄儿童在外环境碘摄入相对稳定的前提下,尿碘浓度是否稳定.另外,进行入户调查,在农村同时采集37名儿童父母(25名父亲、33名母亲)日间1次随意尿样,检测尿碘浓度,探索在日常饮食相近的情况下,学龄儿童的尿碘水平能否代表其父母的尿碘水平;通过“三日称量法”分别调查30名城市儿童和37名农村儿童平均每日的盐摄入量,并且采集37名农村儿童家庭的食盐样品,采用砷铈催化分光光度法检测盐碘.结果 在城市和农村调查点各有440、342名儿童在调查期问未受富碘食品干扰.城市儿童3d尿碘中位数分别为198、188、187 μg/L,组间比较差异无统计学意义(x2=1.7,P＞0.05);农村儿童3d尿碘中位数分别为257、232、202 μg/L,组问比较差异有统计学意义(x2=39.3,P＜ 0.01),且两两比较差异有统计学意义(P均＜0.01).城市和农村学龄儿童连续3d尿碘均＜100μg/L的稳定率分别为12.7％(7/55)和0(0/24),而＞300μg/L的稳定率分别为11.0％(8/73)和22.2％(28/126).37名儿童和其父、母的尿碘水平的Pearson相关结果表明,学龄儿童的尿碘水平与其父母的尿碘水平未呈现相关性[相关系数(r)分别为0.10和0.25,P均＞0.05].城市和农村学龄儿童的平均每日摄盐量分别为(64±2.0)、(6.6±3.4)g;农村儿童家庭盐碘含量为(25.7±10.8)mg/kg.结论 在外环境碘摄入相对稳定的情况下,学龄儿童日间随意1次尿碘水平是波动的;另外,学龄儿童的日间随意1次尿碘水平不能很好地代表其父母尿碘水平.在评价人群碘营养方面需要进行多次监测,目标人群应覆盖多个群体,以便得到更全面、可靠的结果.

abstractsObjective To evaluate the stability of urinary iodine concentration(UIC) of school-age children and examine its representativeness for iodine nutritional status of their parents in order to provide a scientific basis for monitoring and control of iodine deficiency disorders.Methods A cluster sampling method was used,respectively,to recruit 748 and 640 children aged 8-10 in primary schools of Harbin city and surrounding rural areas.A random urine sample was collected once a day for three consecutive days in September 2011.Meanwhile,a parallel questionnaire survey was conducted about iodine-rich food (northern most common foods including kelp,seaweed and other seafood) intake status,during the urine sample collecting period and three days prior to the urine sample collection.UIC of those children,who consumed no iodine-rich food during the urine sample collecting period and three days prior to the urine sample collect ion,was measured by arsenic cerium catalytic spectrophotometry and analyzed in order to evaluate the stability of UIC of school-age children in three consecutive days under relatively constant dietary iodine intake.In addition,a household survey was carried out in rural areas; a random urine sample of 37 children's parents (25 fathers and 33 mothers) was collected once a day to measure UIC for exploring the representativeness of UIC of children for iodine nutritional status of their parents under daily similar diet.Average daily salt intake of 30 urban and 37 rural children was investigated by "three days weighing method",and 37 salt samples were collected from 37 families of children in rural areas to measure iodine concentration with the same method.Results There were 440 and 342 children who did not consume iodine-rich food in the urban and the rural survey sites,respectively.Under relatively constant dietary iodine intake,the medians urinary iodine of UIC of urban children in three consecutive days were 198,188 and 187 μg/L,and there was no statistically significant difference between groups (x2 =1.7,P ＞ 0.05) ; the medians urinary iodineof UIC of rural children were 257,232 and 202 μg/L,and there was a statistically significant difference between groups (x2 =39.3,P ＜ 0.01) ; after pairwise comparisons,the differences were statistically significant (all P ＜ 0.01).Furthermore,the ratios of urban and rural schoolchildren with UIC measurement ＜ 100 μg/L in three consecutive days were 12.7％(7/55) and 0(0/24),respectively; while ＞ 300 μg/L were 11.0％(8/73) and 22.2％(28/126),respectively.Moreover,Pearson test showed that the correlation between UIC of children and their parents was very low (r =0.10 and 0.25,respectively).Besides,average daily salt intake of urban and rural children were (6.4 ± 2.0)g and (6.6 ± 3.4)g.Average iodine concentration in household salt samples was (25.7 ± 10.8)mg/kg.Conclusions UIC in school-age children under relatively constant dietary iodine intake is fluctuating.Besides,a random UIC of children is not a good representative of their parents.When assessing the iodine nutritional status,repeated investigation should be conducted in order to make results more reliable and comprehensive.