Section of Periodontology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.
School of Dentistry and Oral Health, Griffith University, Gold Coast Campus, Southport, QLD, Australia.
Community Dent Oral Epidemiol. 2020 Aug;48(4):264-270. doi: 10.1111/cdoe.12525. Epub 2020 Mar 3.
This cross-sectional study tested the presence of collider bias in the relationship between periodontitis and the carotid intima-media thickness (cIMT).
Data from 480 members of the 1982 Pelotas Birth Cohort, Brazil, were used. Periodontitis at the age of 24 years was determined as the main exposure. cIMT at the age of 30 years was set as the outcome. High-sensitivity C-reactive protein (hsCRP) was considered the mediator (collider). Confounding variables included sex, income, BMI and smoking. The association between cIMT and periodontitis was tested in conventional logistic regression stratified on hsCRP levels, marginal structural modelling and sensitivity analysis for collider stratification bias.
Conventional adjusted logistic regression analysis showed a positive association between periodontitis and cIMT (OR 1.5; 95% CI 1.1; 2.3). Stratified analysis according to the hsCRP levels revealed that the magnitude of the association was even higher among participants with hsCRP ≥ 3 mg/L (OR 2.2, 95% CI 1.1; 4.2) with 36% collider bias probability. No association between periodontitis and cIMT was found among participants with hsCRP < 3 mg/L (OR 1.3; 95% CI 0.8; 2.1). The association was not detected using marginal structural modelling (OR 1.3, 95% CI 0.8; 2.0).
The association between periodontitis and surrogate markers of cardiovascular disease might be induced by collider bias stratification using conventional regression analysis.
本横断面研究旨在检验牙周炎与颈动脉内膜中层厚度（cIMT）之间的关系中是否存在混杂偏倚。
本研究使用了巴西佩洛塔斯出生队列 1982 年队列中 480 名成员的数据。24 岁时的牙周炎被确定为主要暴露因素，30 岁时的 cIMT 被设定为结局。高敏 C 反应蛋白（hsCRP）被认为是中介变量（混杂变量）。混杂变量包括性别、收入、BMI 和吸烟。在 hsCRP 水平分层的常规逻辑回归、边际结构模型和混杂分层偏倚敏感性分析中，检验了 cIMT 与牙周炎之间的关联。
常规调整后的逻辑回归分析显示，牙周炎与 cIMT 呈正相关（OR 1.5；95%CI 1.1；2.3）。根据 hsCRP 水平进行分层分析显示，hsCRP≥3mg/L 的参与者中，这种关联的程度更高（OR 2.2，95%CI 1.1；4.2），混杂偏倚的概率为 36%。在 hsCRP<3mg/L 的参与者中，牙周炎与 cIMT 之间没有关联（OR 1.3；95%CI 0.8；2.1）。边际结构模型也未检测到这种关联（OR 1.3，95%CI 0.8；2.0）。
使用传统回归分析进行混杂分层可能导致牙周炎与心血管疾病替代标志物之间的关联。
