Abstract
Objective:Lung microbiota is increasingly implicated in multiple types of respiratory diseases. However, no study has drawn a consistent conclusion regarding the relationship between changes in the microbial community and lung diseases. This study verifies the association between microbiota level and lung diseases by performing a meta-analysis.Methods:Literature databases, including PubMed, ISI Web of Science, Embase, Google Scholar, PMC, and CNKI, were used to collect related articles published before March 20, 2021. The standard mean deviation (SMD) and related 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup, sensitivity, and publication bias analyses were also conducted.Results:Six studies, comprising 695 patients with lung diseases and 176 healthy individuals, were included in this meta-analysis. The results indicated that the microbiota level was higher in patients with lung diseases than in healthy individuals (SMD = 0.39, 95% CI = 0.22–0.55, I2 = 91.5%, P < 0.01). Subgroup analysis based on country demonstrated that the microbiota level was significantly higher in Chinese (SMD = 1.90, 95% CI = 0.87–2.93, I2 = 62.3%, P < 0.01) and Korean (SMD = 0.24, 95% CI = 0.13–0.35, I2 = 78.7%, P < 0.01) patients with lung diseases. The microbiota level of patients with idiopathic pulmonary fibrosis (IPF) (SMD = 1.40, 95% CI = 0.42–2.38, I2 = 97.3%, P = 0.005), chronic obstructive pulmonary disease (COPD) (SMD = 0.30, 95% CI = 0.09–0.50, I2 = 83.9%, P = 0.004), and asthma (SMD = 0.19, 95% CI = 0.06–0.32, I2 = 69.4%, P = 0.004) were significantly higher than those of the healthy group, whereas a lower microbiota level was found in patients with chronic hypersensitivity pneumonitis (CHP). The microbiota level significantly increased when the disease sample size was >50. Subgroup analysis based on different microbiota genera, indicated that Acinetobacter baumannii and Pseudomonas aeruginosa were significantly increased in COPD and asthma diseases.Conclusion:We observed that patients with IPF, COPD, and asthma had a higher microbiota level, whereas patients with CHP had a lower microbiota level compared to the healthy individuals. The level of A. baumannii and P. aeruginosa were significantly higher in patients with COPD and asthma, and thus represented as potential microbiota markers in the diagnosis and treatment of lung diseases.
Highlights
An abundance of microbiota lives both inside and outside the human body
A total of 8,860 articles were retrieved from PubMed, ISI Web of Science, Embase, and other databases
The present meta-analysis was the first study to indicate that patients with COPD, IPF, and asthma had a higher level of lung microbiota compared to healthy individuals
Summary
An abundance of microbiota lives both inside and outside the human body. Investigation of the microbiota has contributed dramatically to our understanding of their critical role in multiple human diseases, such as cancers, infectious diseases, and lung diseases [1,2,3,4]. The human microbiota comprises bacteria, archaea, viruses, and eukaryotes. These microbiota communities affect human physiological functions, both in health and disease status, contributing to the enhancement or impairment of metabolic and immune functions [6]. Alterations in the microbiota level and composition may lead to an ecological imbalance by decreasing the number of symbionts and increasing potentially dangerous pathogens [7]
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