According to a Childhood Asthma Management Program (CAMP) study, persistent childhood asthma may be linked to earlier development of COPD. The current analysis was part of a randomized placebo-controlled CAMP study that enrolled children ages 5 to 12 years with mild to moderate asthma and followed them into the third decade of life. Researchers identified 684 CAMP participants who had mild to moderate persistent asthma despite medication use. The children were separated into four groups based on their trajectories of lung growth and decline in lung function as measured by FEV1.
The results showed that 75% of children showed abnormal patterns of lung growth before their early 20s; specifically, 26% showed reduced lung growth along with early decline, 23% had reduced lung growth alone, and 26% had normal lung growth and early decline. Additionally, children with a decreased pattern of lung growth or decreased lung function at entry of the study as well as males were at an increased risk. Other factors linked to decreased lung growth included less bronchodilator response young age at study entry, airway hyper responsiveness, vitamin D insufficiency, and number of courses of prednisone.
Overall, the analysis also showed that although COPD rarely develops before the fourth decade of life and often affects current or former smokers, 11% of the children in this study met the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD by age 30. A total of 36% of participants with a reduced lung growth pattern and 8% of those with a normal growth pattern met GOLD criteria for COPD. The authors note that additional studies are needed to identify interventions that could improve outcomes in children with mild to moderate persistent asthma.
According to Medscape, the study could not conclusively assess smoking exposure, a known risk factor for COPD, and could not look at genetic risk factors, prematurity, childhood respiratory infections, and other environmental exposures. Michael J. McGeachie, PhD, and colleagues write, “Our data support the hypothesis that both reduced growth and an early decline are trajectories leading to an asthma–COPD overlap syndrome and complement the recent observation that in older patients, a rapid decline in lung function can lead to COPD.”