母亲与儿童早期龋之间的交互作用: 基于结构方程模型的生命历程研究

Early Childhood Caries (ECC) is one of important childhood disease among preschool children and the prevalence of ECC reached 70%. From fetal stage through infant to young children, diverse time ordered exposures during this period are mutually interconnected to construct a chain of risk which may affect ECC in later life. That is, the effect of exposure may pass on to the next exposure according to the chain of risk, which may subsequently have impact on ECC in later life. However, traditional epidemiological method may not elucidate this dynamic process comprehensively and the interrelationships between diverse exposures may not be investigated. Life course epidemiology may not only investigate the relationships between exposures and ECC, but also explore their own natural history of exposures. The present study will follow up a cohort of infants from fetal stage through infant to young children aged 2 years. Life course approach will be adopted to collect the diverse maternal exposures (including maternal socio-demographic background, maternal oral health related behavior and oral health status, feeding habit and oral hygiene practice to children, vertical transmission of S mutans) during this period comprehensively so that the chain of risk model among diverse exposures and incidence or progression of ECC will be constructed and investigated. Structural Equation Modeling will be used to test this chain of risk model in order to evaluate the effect of previous exposure on the next exposure. The findings from this project will help to understand potential etiological pathways of ECC. Thus, some intervention strategies or programmes may be provided to break the pathways among diverse exposures in the chain of risk model to prevent the incidence of ECC.

儿童早期龋是学龄前儿童最常见的疾病之一，其患病率达70%。婴幼儿从胎儿期开始以时间为顺序的各种暴露因素是相互关联而形成一条完整的危险链影响儿童早期龋,传统的研究方法无法完全揭示这一点。而生命历程方法不仅研究暴露因素和儿童早期龋之间的关系，同时还阐述暴露因素本身自然的发展史。对于这些复杂及环环相扣的生命历程数据的统计分析，结构方程模型能实现每个自变量之间的交互关系和交互作用后对应变量的影响。本项目采用生命历程流行病学方法,追踪随访婴幼儿从胎儿期到婴幼儿2岁，从母亲的角度全面收集各种相关暴露因素，包括母亲的社会经济状况、妊娠的不良结局、母亲自身和对婴幼儿的口腔健康行为和口腔健康状况、变形链球菌的垂直传播等;并利用这些数据构建儿童早期龋发生发展的危险链模型;最后应用结构方程模式验证这一危险链，借此评估上一个暴露因素对下一个暴露因素的影响，以明确各种相关暴露因素对儿童早期龋发生发展的潜在影响机制。

儿童早期龋是学龄前儿童最常见的疾病之一。本项目采用生命历程流行病学方法,在婴幼儿12月龄时纳入20对母亲及婴幼儿，追踪随访婴幼儿从12月龄、18月龄到24月龄。通过问卷调查收集龋病相关的社会、口腔健康相关行为等方面的危险因素，同时采集婴幼儿12、18和24月龄时母亲及其婴幼儿的龈上菌斑样本，运用MiSeq 测序平台进行高通量测序。结果显示，共计有18对母亲及其婴幼儿完成了12、18和24月龄的三次随访。12月时所有婴幼儿均只有乳前牙萌出，无乳磨牙萌出，平均萌出牙数5.6个；18个月时一名幼儿出现两个牙齿的龋白斑，平均萌出牙数11.2个；至24月时，两名幼儿出现三个牙齿的龋白斑，平均萌出牙数15.6个。首先，在婴幼儿12月龄时，微生物多样性Shannon指数表明有龋组和无龋组的母亲之间或婴幼儿之间口腔微生物多样性无显著性差异；而Shannon指数又表明两组内的母亲和婴幼儿口腔微生物多样性均有显著性差异。主成分分析也表明一致的结果。Shannon指数同时表明母亲和婴幼儿之间的口腔微生物多样性呈显著性正相关。以上婴幼儿12月龄时的结果表明母亲的口腔微生物多样性对12月龄的婴幼儿口腔微生物多样性有整体影响，这一结果可能为早期儿童龋风险评估的微生物因素提供更科学的理论依据。其次，本研究项目描绘12-24月龄婴幼儿口腔内的菌群定植、发展及稳定的动态变化过程。婴幼儿12月龄时口内的优势菌属主要为Capnocytophaga、Kingella、Haemophilus、Streptococcus、Neisseria，至18月龄时口内菌群相对稳定，优势菌属主要为Selenomonas、Burkholderia、Erwinia、Cronobacteria、Lactococcus，成长至24月龄时，其优势菌属主要为Lactococcus、Enhydrobacter、Dechloromonas、Bacillus、Enterococcus。12、18和24月龄三个时间点的婴幼儿菌斑样本之间微生物多样性存在显著性差异，而18至24月龄的幼儿阶段样本间的差异相对较小。综上所述，婴幼儿口腔内的菌群呈动态发展趋势，三个时间点之间的微生物群落差异明显，而相比之下，幼儿阶段（18-24月龄）样本间的差异小一些，证明在婴幼儿的成长发育过程中，口腔内的微生物群落逐渐成熟并趋于稳定。