[A panel study on the effect of atmospheric PM2.5 exposure on the gut microbiome in healthy elderly people aged 60-69 years old].

Objective: To analyze the short-term effect of individual atmospheric PM2.5 exposure on the diversity, enterotype, and community structure of gut microbiome in healthy elderly people in Jinan, Shandong province. Methods: The present panel study recruited 76 healthy elderly people aged 60-69 years old in Dianliu Street, Lixia District, Jinan, Shandong Province, and followed them up five times from September 2018 to January 2019. The relevant information was collected by questionnaire, physical examination, precise monitoring of individual PM2.5 exposure, fecal sample collection and gut microbiome 16S rDNA sequencing. The Dirichlet multinomial mixtures (DMM) model was used to analyze the enterotype. Linear mixed effect model and generalized linear mixed effect model were used to analyze the effect of PM2.5 exposure on gut microbiome α diversity indices (Shannon, Simpson, Chao1, and ACE indices), enterotype and abundance of core species. Results: Each of the 76 subjects participated in at least two follow-up visits, resulting in a total of 352 person-visits. The age of 76 subjects was (65.0±2.8) years old with BMI (25.0±2.4) kg/m2. There were 38 males accounting for 50% of the subjects. People with an educational level of primary school or below accounted for 10.5% of the 76 subjects, and those with secondary school and junior college or above accounting for 71.1% and 18.4%. The individual PM2.5 exposure concentration of 76 subjects during the study period was (58.7±53.7) μg/m3. DMM model showed that the subjects could be divided into four enterotypes, which were mainly driven by Bacteroides, Faecalibacterium, Lachnospiraceae, Prevotellaceae, and Ruminococcaceae. Linear mixed effects model showed that different lag periods of PM2.5 exposure were significantly associated with a lower gut α diversity index (FDR<0.05 after correction). Further analysis showed that PM2.5 exposure was significantly associated with changes in the abundances of Firmicutes (Megamonas, Blautia, Streptococcus, etc.) and Bacteroidetes (Alistipes) (FDR<0.05 after correction). Conclusion: Short-term PM2.5 exposure is significantly associated with a decrease in gut microbiome diversity and changes in the abundance of several species of Firmicutes and Bacteroidetes in the elderly. It is necessary to further explore the underlying mechanisms between PM2.5 exposure and the gut microbiome, so as to provide a scientific basis for promoting the intestinal health of the elderly.目的： 分析短期大气PM2.5个体暴露对山东济南健康老年人肠道菌群的多样性、肠型及群落结构的影响。 方法： 采用定群研究设计，在山东省济南市历下区甸柳街道招募76名60~69岁的健康老年人，于2018年9月至2019年1月开展五次随访调查。采用问卷调查、体格检查、个体PM2.5暴露精准监测、粪便样本采集及肠道菌群16S rDNA测序等方法收集相关信息，基于狄利克雷多项混合（DMM）模型进行肠型分析，使用线性混合效应模型和广义线性混合效应模型分析PM2.5暴露对四种肠道菌群α多样性指标（Shannon、Simpson、Chao1和ACE指数）、肠型和核心菌群物种丰度的影响。 结果： 76名研究对象中每人均至少参与了两次随访，最终共纳入352人次。76名研究对象年龄为（65.0±2.8）岁；BMI为（25.0±2.4）kg/m2；男性38名（50%）；小学及以下、中学、大专及以上分别占10.5%、71.1%和18.4%。研究期间76名对象的PM2.5个体暴露浓度为（58.7±53.7）μg/m3。DMM模型显示，研究对象可分为四种肠型，主要由拟杆菌、粪杆菌、毛螺菌、普雷沃菌和瘤胃球菌等菌群驱动。线性混合效应模型显示：不同滞后期PM2.5个体暴露水平与肠道α多样性指数下降有关联［校正后的错误发现率（FDR）均<0.05］；进一步分析发现PM2.5暴露主要与厚壁菌门（如巨单胞菌属、经黏液真杆菌属和链球菌属等）和拟杆菌门（另枝菌属）的丰度改变有关联（校正后FDR<0.05）。 结论： 短期PM2.5个体暴露与健康老年人肠道菌群多样性指数下降有关联，并与厚壁菌门和拟杆菌门多个物种的丰度变化存在关联。.