Pediatrics, Department of Medical and Surgical Sciences, University of Foggia Medical School, Foggia, Italy.
Pediatrics, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (Foggia), Italy.
Am J Clin Nutr. 2019 Apr 1;109(4):1080-1087. doi: 10.1093/ajcn/nqy393.
Iodine is an essential micronutrient for intellectual development in children. Information on iodine intakes based on 24-h urinary iodine excretion (UIE) is scant, because iodine status is only assessed by the measurement of urinary iodine concentration (UIC) in spot urine samples.
The aim of our study was to evaluate the iodine intake of school-age children and adolescents, using UIE measurement in 24-h urine collections.
The study population included 1270 healthy subjects (677 boys, 593 girls) aged 6-18 y (mean age ± SD: 10.3 ± 2.9) from 10 Italian regions. Daily iodine intake was estimated as UIE/0.92, based on the notion that $\sim$92% of the dietary iodine intake is absorbed. The adequacy of intakes was assessed according to the Dietary Reference Values for iodine of the European Food Safety Authority (EFSA). Body mass index (BMI) and UIC were also measured for each subject.
Based on the scientific opinion of EFSA, 600 of 1270 subjects (47.2%) had a lower than adequate iodine intake, with a higher prevalence among girls (54.6%) compared with boys (40.2%) (P < 0.001). Although UIE and 24-h urinary volumes increased with age (P < 0.001), a progressive decrease in the percentage of subjects with iodine excretion <100 µg/24 h (P < 0.001) was observed, without any significant difference in the percentage of subjects with UIC <100 µg/L. No significant association was detected between BMI z-score and UIE (P = 0.603) or UIC (P = 0.869).
A sizable proportion of our population, especially girls, appeared to be at risk of iodine inadequacy. The simple measurement of UIC could lead to underestimation of the occurrence of iodine deficiency in younger children, because of the age-related smaller urine volumes producing spuriously higher iodine concentrations.
碘是儿童智力发育所必需的微量元素。基于 24 小时尿碘排泄量（UIE）的碘摄入量信息很少，因为只有通过测量单次尿样中的尿碘浓度（UIC）来评估碘的状态。
本研究旨在通过 24 小时尿液收集来评估学龄儿童和青少年的碘摄入量。
研究人群包括来自意大利 10 个地区的 1270 名健康受试者（677 名男孩，593 名女孩），年龄 6-18 岁（平均年龄±标准差：10.3±2.9）。根据饮食碘摄入量约 92%被吸收的观点，每日碘摄入量估计为 UIE/0.92。根据欧洲食品安全局（EFSA）碘的膳食参考值评估摄入量的充足性。还为每位受试者测量了体重指数（BMI）和 UIC。
根据 EFSA 的科学意见，1270 名受试者中有 600 名（47.2%）碘摄入量不足，其中女孩（54.6%）的患病率高于男孩（40.2%）（P<0.001）。尽管 UIE 和 24 小时尿排量随年龄增长而增加（P<0.001），但观察到碘排泄量<100μg/24 h 的受试者比例逐渐下降（P<0.001），UIC<100μg/L 的受试者比例没有差异。未检测到 BMI z 评分与 UIE（P=0.603）或 UIC（P=0.869）之间存在显著相关性。
我们的人群中相当一部分，尤其是女孩，似乎有碘不足的风险。由于与年龄相关的尿液量较小导致碘浓度假性升高，因此简单测量 UIC 可能会低估年龄较小儿童的碘缺乏发生率。
