重庆地区儿童尿碘重复测量数据混合线性模型研究

Mixed Linear Models Used for Repeated Measurement of Urine Iodine Level:Evidence from Children in Chongqing

为研究8～10岁儿童白天时段尿碘含量变化规律,给统一尿样采集时间提供理论依据,采集重庆市区一所住宿小学的60名8～10岁儿童1 d的晨尿、10:00 am、12:30、4:00 pm时段的尿样,采用砷铈催化分光光度法检测了尿碘含量,用混合线性模型(mixed linear models)分析了尿碘数据。结果表明,不同年龄、不同时间点的尿碘含量存在差异,10:00 am尿与晨尿尿碘值最为接近。提示应用10:00 am尿样通过乘以校正系数1.094,0.997和1.072的修正值代替晨尿可以使尿碘水平具有代表性和可行性,混合线性模型能够有效地处理重复测量数据。

To explore the variation of urine iodine level in daytime from children aged 8 - 10, so as to provide evidence for unifying the sampling time, urine samples from 60 pupils were collected in early morning, at 10：00 am, 12：30 and 4：00 pm respectively. Those samples were then detected by speetrophotometric eerie - arsenic assay to measure the urine iodine. Mixed linear models were used to deal with the urine iodine data. The results whows that there were significant differences among urine iodine levels from various age groups and time points. The urine iodine level from 10：00 am and early morning urine shared similarities. It is feasible to use the 10：00 am urine sample instead of morning urine sample by multiplying correction factors as 1. 094, 0. 997 and 1. 072. Mixed linear models can effectively deal with repeated measurement data.