Three-quarters of COPD cases have their origins in poor lung function pathways beginning in childhood, and are amplified by factors in adulthood, according to a study published in The Lancet Respiratory Medicine.

While smoking remains the biggest risk factor for COPD, the study demonstrates that childhood illnesses (such as asthma, bronchitis, pneumonia, allergic rhinitis, eczema) and exposures to parental smoking are also linked to the disease.

In the first study, 2,438 participants from the Tasmanian Longitudinal Health Study (Australia) were tracked from childhood to the age of 53 – making it the largest and longest-running study of its kind. Lung function was measured at the ages of 7, 13, 18, 45, 50 and 53 years old, and participants’ exposure to various risk factors was also recorded.

The authors identified six distinct pathways describing how lung function changes with age. Three of these pathways were associated with COPD – the group with below average lung function in early life and a quick decline in lung function in later life, those with persistently low lung function, and those with below average lung function. Combined, these three pathways were linked to an estimated three-quarters of all cases of COPD occurring at the age of 53 (75.2% overall). For moderate-to-severe COPD, all cases only arose from these three trajectories.