Smoking-induced microbial dysbiosis: a key driver of systemic diseases and emerging therapeutic opportunities.

Tobacco use, including both traditional and electronic cigarettes, profoundly alters host-microbiota interactions, contributing to the pathogenesis of various systemic diseases. Smoking-induced microbial dysbiosis impacts multiple anatomical sites, including the oral cavity, respiratory tract, and gastrointestinal system, driving disease progression through mechanisms such as immune modulation, chronic inflammation, and metabolic dysregulation. This review examines the disruption of microbial ecosystems by smoking, with a focus on the imbalance between beneficial and pathogenic microorganisms. In the oral cavity, smoking is strongly linked to diseases such as periodontitis and oral cancer, marked by shifts in microbial diversity and functional profiles. Similar dysbiotic changes are observed in the respiratory and gastrointestinal systems, where smoking impairs mucosal immunity, increases oxidative stress, and compromises barrier integrity, thereby enhancing susceptibility to chronic diseases. Additionally, the review addresses the challenges in establishing causality between microbial changes and disease outcomes, emphasizing the need for more comprehensive research utilizing multi-omics approaches and longitudinal studies. By exploring the potential for microbiota-based interventions, this review underscores the critical role of microbial dysbiosis in smoking-related health risks, providing valuable insights for the development of targeted therapeutic strategies to mitigate the global health burden of tobacco use.