[Association between periodontitis and mild cognitive impairment: a clinical pilot study].

Objective: To evaluate the association between periodontitis and mild cognitive impairment (MCI), and explore the potential local oral risk factors for MCI. Methods: The study included 70 middle-aged and elderly subjects (44 females and 26 males) with periodontal disease who were first diagnosed by the Department of Periodontology or referred by the Department of Geriatrics in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from January 2021 to January 2022. In this study, the control group consisted of periodontal disease patients without cognitive impairment, and the case group (MCI group) consisted of those diagnosed with MCI referred by the geriatrics specialists. Full-mouth periodontal examinations of all subjects were performed and periodontal indicators were recorded by periodontists, while digital panoramic radiographs were taken. The severity of periodontitis was defined according to the 1999 classification, and the staging and grading of periodontitis were defined according to the 2018 American Academy of Periodontology and European Federation of Periodontology classification. The mini-mental state examination scale was chosen by geriatricians to evaluate the cognitive function of the included subjects. The cubital venous blood was drawn to detect the expression levels of inflammatory factors such as hypersensitive C-reactive protein (hs-CRP), interleukin (IL)-1β, IL-6 and tumor necrosis factor-α(TNF-α) in serum. Independent-samples t test and chi-square test were used to analyze the differences in population factors, periodontal-related indexes and serum inflammatory factors between the two groups (α=0.05). Odds ratios (OR) for MCI according to the severity of periodontitis and main periodontal clinical indexes were calculated by binary Logistic analysis. Results: Thirty-nine subjects were included in the control group and thirty-one in the MCI group. The age of the study population was (58.3±6.2) years (range: 45-70 years). The comparison between two groups showed that the control group was with higher educational background (χ²=9.45, P=0.024) and 2.6 years younger than the MCI group [(57.1±6.0) years vs. (59.7±6.3) years, t=-1.24, P=0.082]. The number and proportion of moderate to severe periodontitis in control group were significantly lower compared to those in MCI group (17 cases with 43.6% vs. 23 cases with 74.2%, χ²=6.61, P=0.010), and the OR of moderate to severe periodontitis adjusted by age and educational background was 3.00 (95%CI: 1.01-8.86, P=0.048). Compared with the grading (χ²=5.56, P=0.062) of periodontitis, staging had a greater impact on MCI (χ²=7.69, P=0.041), moreover the proportion of MCI in stage Ⅰ grade A periodontitis was significantly lower than any other type of periodontitis (χ²=13.86, P=0.036). In addition, less presence of deep periodontal pockets [probing depth (PD)≥6 mm] (17.9% vs. 41.9%, χ²=4.87, P=0.027), fewer number of PD≥4 mm (6.48±6.70 vs. 11.03±8.91, t=-2.44, P=0.017), lower plaque index (1.42±0.56 vs. 1.68±0.57, t=-1.91, P=0.059) and gingival index (1.68±0.29 vs. 1.96±0.30, t=-3.93, P<0.001) were in the control group than in the MCI group. However, there were no significant differences between the two groups in the levels of serum inflammatory factors, such as hs-CRP, IL-1β, IL-6 and TNF-α (P>0.05). Conclusions: It appears a strong correlation between moderate to severe periodontitis and the incidence of MCI in middle-aged and elderly people. Moreover, deep and increased number of periodontal pockets, poor oral hygiene, and severe gingival inflammation can be potentially associated risk factors for MCI.目的： 评估不同程度牙周炎对轻度认知障碍（mild cognitive impairment，MCI）的影响，寻找MCI的潜在口腔局部风险因素，探索牙周炎与MCI之间的关系。 方法： 研究纳入2021年1月至2022年1月于上海交通大学医学院附属第九人民医院牙周病科首诊或老年病科转诊的中老年牙周病患者共70例（女性44例，男性26例）。对照组为认知正常的牙周病患者，病例组（MCI组）为老年病科转诊的确诊MCI的牙周病患者。由牙周专科医师对所有研究对象进行全口牙周检查、记录相关牙周指标并拍摄曲面体层X线片，按1999年分类定义牙周炎的分度，按2018年分类定义牙周炎的分期和分级。由老年病专科医师使用简易精神状态评价量表评估研究对象的认知功能。抽取所有研究对象的肘静脉血以检测血清中超敏C反应蛋白（hypersensitive C-reactive protein，hs-CRP）、白细胞介素（interleukin，IL）-1β、IL-6和肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）等炎症因子水平。采用独立样本t检验和χ²检验分析人群因素、牙周相关指标和血清炎症指标在两组间的差异，二元Logistic分析计算研究对象牙周炎程度及主要牙周临床指标的MCI比值比（odds ratio，OR）。 结果： 对照组共纳入39例、MCI组纳入31例患者。70例研究对象年龄（58.3±6.2）岁（45~70岁），组间比较显示对照组中高学历人群占比显著高于MCI组（χ²=9.45，P=0.024），对照组年龄［（57.1±6.0）岁］与MCI组［（59.7±6.3）岁］相比差异无统计学意义（t=-1.24，P=0.082）。对照组中重度牙周炎患者例数及占比［43.6%（17/39）］显著低于MCI组［74.2%（23/31）］（χ²=6.61，P=0.010），中重度牙周炎在纳入年龄和学历校正后的OR值为3.00（95%CI：1.01~8.86，P=0.048）。牙周炎分级的组间分布差异无统计学意义（χ²=5.56，P=0.062），牙周炎分期（χ²=7.69，P=0.041）及分期分级（χ²=13.86，P=0.036）的组间分布差异均有统计学意义。此外，对照组相比MCI组，存在探诊深度≥6 mm深牙周袋者占比更低（17.9%对比41.9%，χ²=4.87，P=0.027），探诊深度≥4 mm位点数更少［（6.48±6.70）个对比（11.03±8.91）个，t=-2.44，P=0.017］，菌斑指数（1.42±0.56对比1.68±0.57，t=-1.91，P=0.059）和牙龈指数（1.68±0.29对比1.96±0.30，t=-3.93，P<0.001）也更低，组间差异均有统计学意义。但两组间血清炎症因子hs-CRP、IL-1β、IL-6及TNF-α水平差异均无统计学意义（P>0.05）。 结论： 本组中老年人群中重度牙周炎与MCI发病有较强的关联；存在较深牙周袋且牙周袋数量较多、口腔卫生不良和牙龈炎症较重也是MCI潜在的风险因素。.