Three-quarters of COPD cases start from poor lung function in childhood, associated with exposure to parental smoking or conditions such as asthma, hayfever and eczema, according to a study 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 passive smoking are also linked to the disease.1
A second study in the journal also suggests that there could be a window of opportunity during childhood to reduce the risk of poor lung function in later life.2
Both studies identified pathways of how lung function changes over life, which are associated with different risk factors and disease risk in later life. The authors say that these insights are important for lung disease prediction, prevention, and treatment.
‘These findings highlight the importance of preventing both early life adverse exposures that could lead to poorer lung growth, and adult risk factors contributing to accelerated lung decline. COPD is expected to be the third largest cause of death globally by 2030, and it is important that we identify its key causes so that this burden can be reduced,’ says study author Professor Shyamali Dharmage, School of Population and Global Health, The University of Melbourne, Australia.
The first study, the largest and longest-running study of its kind, identified six distinct pathways describing how lung function changes with age. Three of these pathways were associated with COPD, and account for 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 routes.
The authors suggest that the childhood risk factors are aggravated by smoking and having asthma in adulthood.
The second study found that around three-quarters of infants aged 1-6 months with poor lung function improved throughout their childhood, indicating a window of opportunity to increase lung function and potentially reduce risk of COPD in later life. They suggest that interventions to maximise lung growth in early childhood might modify the risk of COPD in older age.
1. Bui DS, et al. Lancet Respir Med 2018. Published online 5 April. https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(18)30100-0/fulltext
2. Belgrave DCM, et al. Lancet Respir Med 2018. Published online 5 April https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(18)30099-7/fulltext
