The long tail of childhood bronchitis

A landmark study examines the connection between early lung infections and respiratory issues in middle age.

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Children who have bronchitis at least once before the age of seven are at greater risk of lung problems later in life, new Australian research has revealed.

The most common lung diseases to affect people by their 50s were asthma and pneumonia, rather than chronic bronchitis or COPD.

Researchers from the Allergy and Lung Health Unit at the University of Melbourne have published their findings this week in the BMJ Open Respiratory Researchjournal.

Longitudinal cohort studies from early life to adulthood have provided important insights into lung disease development, including one published in 2009 in the Proceedings of the American Thoracis Society journal and the European Respiratory Journal in 2014.

“While several studies have supported the role of early life exposures in adult lung function deficits and chronic obstructive pulmonary disease (COPD), the early origins of adult chronic productive cough (or CB) remain poorly understood and sparsely studied,” the authors of the BMJ article wrote.

Lead author Dr Jennifer Perret said the findings came from one of the world’s oldest surveys, the Tasmanian Longitudinal Health Study, which followed 8583 people who were born in Tasmania in 1961.

“This is the first very long-term prospective study that has examined the relationship between childhood bronchitis severity with adult lung health outcomes,” she said.

“We have seen already that children with protracted bacterial bronchitis are at increased risk of serious chronic infective lung disease after two to five years, so studies like ours are documenting the potential for symptomatic children to develop lung conditions, such as asthma and lung function changes, up to mid-adult life.”

Researchers established the link between childhood bronchitis and adult lung problems by surveying the original participants when they joined the study.

Participants were then tracked for an average of 46 years, with 42% completing another questionnaire, including doctor-diagnosed lung conditions and a clinical examination, between 2012 and 2016.

They found that the more often a doctor had diagnosed a participant as having pneumonia and asthma, the more likely the participant was to have had bronchitis as a child.

Interestingly, among those most affected by childhood bronchitis, the researchers found associations with current asthma in middle age which were evident even for participants without a history of childhood asthma/wheezing at age seven.

“This suggests that a predisposition to multiple and protracted episodes of childhood bronchitis could lead to damaged airways, and that a degree of airway narrowing from remodelling could impair normal airway development to manifest as symptomatic asthma in later life,” they wrote.

Dr Perret said the numbers in the most severe subgroup were small (just 42 participants were in this category and of these just 14 had current asthma in middle age), but the trends across bronchitis severity categories were significant.

“Compared with the majority who never had from bronchitis, there was an incremental increase in risk for later asthma and pneumonia which strengthened the more often a person had suffered from bronchitis as a child, and especially if they had recurrent episodes which were prolonged for at least one month in duration,” she said.

“It is notable that the link with later adult active asthma was seen for participants who did not have co-existent asthma or wheezing in childhood, and a similar finding has been recently seen in a very large meta-analysis of school-aged children who had had a lower respiratory tract infection during early childhood.”

Researchers hope the study will help doctors identify children who could benefit from more careful monitoring and earlier interventions to keep them in better health into mid-adult life.

“This study’s findings support the need for increased vigilance in monitoring young children who have multiple episodes of protracted bronchitis for potential asthma, pneumonia and bronchiectasis up to mid-adult life, confirmed with objective testing,” they wrote.