[A cohort study on the association between dynamics of thyroid volume and the changes of physical growth as well as the comparison of different thyroid volume indexes in school-aged children].

Objectives: To investigate the association between the dynamics of thyroid volume and the changes of physical growth in school-aged children as well as to compare the applicability of different thyroid volume indexes, so as to explore more reliable methods for the assessment of thyroid volume. Methods: In October 2012, a multi-stage cluster sampling method was used to select a primary school in Minhang district of Shanghai, Haimen city of Jiangsu province and Yuhuan city of Zhejiang province, respectively. In these areas, a total number of 784 students aged 8-10 years were enrolled in the cohort. Demographic data was collected, while height and weight were measured, with BMI and body surface area (BSA) were calculated. Thyroid volume was examined by B-ultrasonography. Height volume index (HVI), weight and height volume index (WHVI), BMI volume index (BMIV) and BSA volume index (BSAV) were all applied to correct the thyroid volume. All students were followed up, one year later. Results: A total of 769 students with complete data on thyroid volume and physical growth were enrolled, including 378 boys (49.16%) and 391 girls (50.84%). Thyroid volume showed an increase with age, while growth of thyroid volume reduced with the increase of age (P<0.001). The thyroid volume showed a correlation with the changes of physical growth. The growth of height appeared as the dominant influencing factor for thyroid volume growth in those aged 8 and 10 years (P<0.05), while the growth of weight, BMI and BSA were all influencing factors for thyroid volume on students aged 9 years (P<0.05). Conclusions: Thyroid volume in school-aged children was a factor not only associated with age but also with physical growth which had not been considered in the currently used criteria. The inclusion of items as iodine intake, age, physical growth into the thyroid volume indexes seemed to be more reliable, in practice. For the assessment of goiter, HVI for students aged 8 and 10 years and BMIV for students aged 9 years might serve as better indicators.目的： 分析学龄儿童甲状腺容积变化与体格发育变化的关联，比较不同甲状腺容积指数对于学龄儿童的适用性，从而探索稳定有效的甲状腺容积校正方法。 方法： 2012年10月，采用分阶段整群抽样的方法，分别在上海市闵行区、江苏省海门市、浙江省玉环市各选定1所小学，将3所小学中所有8~10岁学龄儿童共784名纳入研究队列中。获取研究对象的基本人口学信息，测量其身高、体重，并计算BMI、体表面积（BSA）等体格发育指标。采用B超检查测定研究对象甲状腺容积大小，使用身高容积指数（HVI）、体重身高容积指数（WHVI）、体质容积指数（BMIV）及BSA容积指数（BSAV）对甲状腺容积进行校正。于1年后对研究对象进行随访。 结果： 共获得769名学龄儿童甲状腺容积及体格发育的有效数据，其中男生378名（49.16%），女生391名（50.84%）。甲状腺容积随年龄增大而增大，甲状腺容积差值随年龄增大而减小（P<0.001）。各年龄组甲状腺容积变化在一定程度上与体格发育变化有关，但表现均不一致。8岁组及10岁组中，身高差值为主要影响因素（P<0.05）；而9岁组中，体重、BMI、BSA差值为影响因素（P<0.05）。 结论： 学龄儿童甲状腺容积受年龄、身高、体重等影响，现行仅以年龄划定的甲状腺肿大判定标准需进一步改进，应根据研究对象碘摄入量、年龄、体格发育等多因素，选择最优的甲状腺容积校正指数。在判定甲状腺肿大与否时，HVI对于8岁组及10岁组、BMIV对于9岁组具有很好的评价适用性。.