June 08, 2022

Early-Life Respiratory Tract Infections, School-Age Asthma, and Lung Function

Young children who develop upper respiratory tract infections may have an increased chance of developing asthma at school age. Young children who develop lower respiratory tract infections have a greater risk of school-age airway blockage, airflow restriction, and developing asthma, according to study results published recently in the European Respiratory Journal.

A few recent studies suggest that young children with respiratory infections are more inclined toward asthma and other chronic respiratory diseases later in life. Researchers sought to investigate the connection between upper and lower respiratory tract infections in young children and the risks for subsequent respiratory problems and asthma at school age.

To accomplish this, they conducted a retrospective meta-analysis of data from 150,090 children (6 months to 5 years of age, born between 1989 and 2013) mostly from the European Union Cohort Network. The investigators analyzed the relationships between early-life upper and lower respiratory tract infections, pulmonary function, and school-age asthma in study participants. School-age asthma and lung function were the primary outcomes. Lung function measures assessed included: expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), FEV₁/FVC, and forced expiratory flow at 75% of FVC (FEF₇₅).

Among the children studied, infections registered most frequently at 1 year of age (mean upper tract respiratory infections 63.0%; lower tract respiratory infections 23.0%) and decreased until 5 years of age (upper tract respiratory infections 42.6%; lower tract respiratory infections 15.0%). Asthma developed in 12.3% of these children.

Young children developing lower respiratory tract infections subsequently showed lower FEV₁, FEV₁/FVC, and FEF₇₅ at school age. These children with lower respiratory tract infections displayed a greater risk of school-age asthma than young children developing upper respiratory tract infections.

“These results suggest that predominantly lower respiratory tract infections could have a direct effect on lung development, and subsequent chronic respiratory diseases,” the investigators concluded. Study limitations included the fact that lung function data was available for less than 20% of participants and was completely lacking for participants in early life. Further, no asthma diagnosis was confirmed with bronchodilator reversibility.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.