Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.
Allergy. 2015 Aug;70(8):973-84. doi: 10.1111/all.12640. Epub 2015 May 20.
Asthma, rhinitis and eczema often co-occur in children, but their interrelationships at the population level have been poorly addressed. We assessed co-occurrence of childhood asthma, rhinitis and eczema using unsupervised statistical techniques.
We included 17 209 children at 4 years and 14 585 at 8 years from seven European population-based birth cohorts (MeDALL project). At each age period, children were grouped, using partitioning cluster analysis, according to the distribution of 23 variables covering symptoms 'ever' and 'in the last 12 months', doctor diagnosis, age of onset and treatments of asthma, rhinitis and eczema; immunoglobulin E sensitization; weight; and height. We tested the sensitivity of our estimates to subject and variable selections, and to different statistical approaches, including latent class analysis and self-organizing maps.
Two groups were identified as the optimal way to cluster the data at both age periods and in all sensitivity analyses. The first (reference) group at 4 and 8 years (including 70% and 79% of children, respectively) was characterized by a low prevalence of symptoms and sensitization, whereas the second (symptomatic) group exhibited more frequent symptoms and sensitization. Ninety-nine percentage of children with comorbidities (co-occurrence of asthma, rhinitis and/or eczema) were included in the symptomatic group at both ages. The children's characteristics in both groups were consistent in all sensitivity analyses.
At 4 and 8 years, at the population level, asthma, rhinitis and eczema can be classified together as an allergic comorbidity cluster. Future research including time-repeated assessments and biological data will help understanding the interrelationships between these diseases.
哮喘、鼻炎和湿疹在儿童中常同时发生，但人群水平上它们之间的相互关系尚未得到充分研究。我们使用无监督统计技术评估了儿童哮喘、鼻炎和湿疹的同时发生情况。
我们纳入了来自七个欧洲基于人群的出生队列的 17209 名 4 岁儿童和 14585 名 8 岁儿童（MeDALL 项目）。在每个年龄阶段，我们使用分区聚类分析根据 23 个变量的分布将儿童分组，这些变量包括症状“曾有”和“过去 12 个月内”、医生诊断、哮喘、鼻炎和湿疹的发病年龄和治疗、免疫球蛋白 E 致敏、体重和身高。我们测试了我们的估计值对受试者和变量选择以及不同统计方法（包括潜在类别分析和自组织映射）的敏感性。
在两个年龄阶段和所有敏感性分析中，我们发现将数据聚类为两组是最佳方法。第一个（参考）组在 4 岁和 8 岁时（分别包括 70%和 79%的儿童）的特点是症状和致敏的患病率较低，而第二个（症状性）组则表现出更频繁的症状和致敏。在两个年龄阶段，99%的共病（哮喘、鼻炎和/或湿疹共存）儿童都被归入症状性组。在所有敏感性分析中，两组儿童的特征都是一致的。
在人群水平上，4 岁和 8 岁时，哮喘、鼻炎和湿疹可以被归类为过敏共病集群。未来包括时间重复评估和生物学数据的研究将有助于理解这些疾病之间的相互关系。
