Early-Life Gut Microbiota and the Pediatric Gut-Lung Axis: A Systematic Review of Clinical, Preclinical, and Mechanistic Evidence

Background/Objectives: The early-life gut microbiota plays a pivotal role in immune maturation and may influence respiratory health through the gut-lung axis. However, evidence linking microbial development, dysbiosis, microbial metabolites, and microbiota-targeted interventions to pediatric respiratory outcomes remains heterogeneous. This systematic review aimed to synthesize clinical and preclinical evidence on the pediatric gut-lung axis and its underlying mechanisms.