Harrist Ronald B, Dai Shifan
School of Public Health, University of Texas Health Science Center at Houston, 313 E. 12th Street, Austin TX 78701, USA.
Am J Prev Med. 2009 Jul;37(1 Suppl):S17-24. doi: 10.1016/j.amepre.2009.04.004.
Project HeartBeat! (1991-1995) was an observational study of the development of cardiovascular disease (CVD) risk factors in childhood and adolescence using an accelerated longitudinal design. The purpose of this paper is to explain the analytic methods used in the study, particularly multilevel statistical models. Measurements of hemodynamic, lipid, anthropometric, and other variables were obtained in 678 children who were enrolled in three cohorts (baseline ages 8, 11, and 14 years) and followed for 4 years, resulting in data for children aged 8-18 years. Patterns of change of blood pressure, serum lipid concentration, and obesity with age, race, and gender were of particular interest. The design specified 12 measurements of each outcome variable per child. Multilevel models were used to account for correlations resulting from repeated measurements on individuals and to allow use of data from incomplete cases. Data quality-control measures are described, and an example of multilevel analysis in Project HeartBeat! is presented. Multilevel models were also used to show that there were no differences attributable to the cohorts, and combining data from the three age cohorts was judged to be reasonable. Anthropometric data were compared with national norms and shown to have similar patterns; thus, the patterns seen in the CVD risk factors may be generalized, with some caveats, to the U.S. population of children.
“心跳计划”（1991 - 1995年）是一项采用加速纵向设计对儿童和青少年心血管疾病（CVD）危险因素发展情况进行的观察性研究。本文旨在解释该研究中使用的分析方法，特别是多水平统计模型。对678名儿童进行了血流动力学、血脂、人体测量学及其他变量的测量，这些儿童被纳入三个队列（基线年龄分别为8岁、11岁和14岁），并随访4年，从而获得了8至18岁儿童的数据。血压、血清脂质浓度和肥胖程度随年龄、种族和性别的变化模式尤其令人关注。该设计规定每个儿童对每个结局变量进行12次测量。多水平模型用于解释个体重复测量产生的相关性，并允许使用来自不完整病例的数据。描述了数据质量控制措施，并给出了“心跳计划”中多水平分析的一个例子。多水平模型还用于表明各队列之间没有差异，并且将三个年龄队列的数据合并被认为是合理的。人体测量数据与全国标准进行了比较，显示出相似的模式；因此，在心血管疾病危险因素中观察到的模式在一定条件下可能适用于美国儿童人群。
