Robust Clustering With Subpopulation-Specific Deviations

The National Birth Defects Prevention Study (NBDPS) is a case-control study of birth defects conducted across 10 U.S. states. Researchers are interested in characterizing the etiologic role of maternal diet, collected using a food frequency questionnaire. Because diet is multidimensional, dimension reduction methods such as cluster analysis are often used to summarize dietary patterns. In a large, heterogeneous population, traditional clustering methods, such as latent class analysis, used to estimate dietary patterns can produce a large number of clusters due to a variety of factors, including study size and regional diversity. These factors result in a loss of interpretability of patterns that may differ due to minor consumption changes. Based on adaptation of the local partition process, we propose a new method, robust profile clustering, to handle these data complexities. Here, participants may be clustered at two levels: (1) globally, where women are assigned to an overall population-level cluster via an overfitted finite mixture model, and (2) locally, where regional variations in diet are accommodated via a beta-Bernoulli process dependent on subpopulation differences. We use our method to analyze the NBDPS data, deriving prepregnancy dietary patterns for women in the NBDPS while accounting for regional variability. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.国家出生缺陷预防研究（National Birth Defects Prevention Study, NBDPS）是一项在美国10个州开展的出生缺陷病例对照研究。研究人员旨在通过食物频率问卷（food frequency questionnaire）收集的母亲膳食数据，阐明其病因学作用。由于膳食具有多维度特征，聚类分析（cluster analysis）等降维方法常被用于总结膳食模式。在大型异质性人群中，用于估计膳食模式的传统聚类方法（如潜在类别分析（latent class analysis)）可能会因研究规模、区域多样性等多种因素生成大量聚类簇，进而导致由细微消费差异形成的膳食模式丧失可解释性。基于局部划分过程（local partition process）的改进思路，我们提出一种名为稳健轮廓聚类（robust profile clustering）的新方法，以应对此类数据复杂性问题。该方法可在两个层级对参与者进行聚类：（1）全局层级：通过过拟合有限混合模型（finite mixture model）将女性归至总体人群水平的聚类簇；（2）局部层级：通过依赖亚群差异的β-伯努利过程（beta-Bernoulli process）适配膳食的区域变异特征。我们将所提方法应用于NBDPS数据分析，在考量区域变异的前提下，推导得到该研究中女性的孕前膳食模式。本文的补充材料（包括可用于复现研究的标准化材料说明）可通过在线补充资料获取。