Chronic Bronchitis in Children and Adults: Definitions, Pathophysiology, Prevalence, Risk Factors, and Consequences

Area of Science:

• Respiratory Medicine
• Pediatric Pulmonology
• Epidemiology

Background:

• Chronic bronchitis (CB) definitions have evolved, complicating understanding of its causes and impact.
• Childhood CB, termed protracted bacterial bronchitis (PBB), involves persistent airway inflammation often due to bacterial infections.
• Childhood CB may persist into adulthood and is linked to asthma, bronchiectasis, and COPD.

Purpose of the Study:

• To review the current evidence on the evolution of definitions, pathophysiology, risk factors, and consequences of chronic bronchitis in both children and adults.
• To highlight the intricate interplay between risk factors, childhood CB, adult CB, and other chronic respiratory conditions.
• To underscore the need for longitudinal studies to clarify the natural history of CB across the lifespan.

Main Methods:

• Systematic review of existing literature on chronic bronchitis.
• Analysis of studies focusing on definitions, etiology, and clinical outcomes.
• Synthesis of evidence regarding the transition from childhood PBB to adult CB and associated respiratory diseases.

Main Results:

• CB presents differently in children (PBB) and adults, with distinct etiological factors.
• A subset of childhood CB progresses to adult CB, increasing the risk for other chronic respiratory diseases.
• Longitudinal data on CB progression and its long-term consequences are limited.

Conclusions:

• Understanding the lifelong trajectory of chronic bronchitis requires further comprehensive longitudinal research.
• Early identification and management of PBB may be crucial for preventing long-term respiratory morbidity.
• The review synthesizes current knowledge, identifying gaps in understanding the natural history of CB.