Wheezing an Independent Risk Factor of Asthma in Young Adults

A controlled questionnaire study confirmed that early-childhood hospitalizations for lower respiratory infection with wheezing was an independently significant risk factor of asthma in young adults.

With their study, investigators led by Matti Korppi, Department of Pediatrics, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland, aimed to evaluate doctor-diagnosed and self-reported asthma in young adults in early-childhood hospitalization for wheezing.

Previous data revealed an increased risk of asthma in children with wheezing during lower respiratory infections in early childhood was increase, with complications occurring beyond puberty.

Hospitalization for wheezing in young childhood had often been associated with respiratory virus infection caused by respiratory syncytial virus (RSV) or rhinovirus, with rhinoviruses playing a role in the later development of asthma.

Korppi and investigators detailed the occurrence of doctor-diagnosed and self-reported asthma in young adults after hospitalization for their first episode of wheezing under 24 months of age compared to population-based controls

In addition, they evaluated potential risk factors for asthma with a focus on weight, allergy and smoking, and RSV and rhinovirus identification during early-childhood hospitalization.

The Study

Of the 100 children who were hospitalized for the first infection-associated episode of wheezing at age younger than 24 months between 1992-1993 in Kuopio University Hospital, Finland, 92 of them participated in the prospectively scheduled follow-ups during 12 months after hospitalization.

A control group of 100 people had also participated in the study.

Overall, 6 respiratory viruses including RSV were studied by antigen detection during hospitalization at younger than 24 months of age.

Investigators issued a questionnaire with questions regarding the presence of wheezing symptoms, prolonged cough apart from infection, repeated night cough, nasal symptoms suggestive for allergic rhinitis and skin symptoms suggestive for atopic dermatitis.

Additionally, the presence of doctor-diagnosed asthma, the use of maintenance medication for asthma, and the need of on-demand bronchodilator medication for wheezing or asthma were asked.

Respiratory and skin symptoms and the use of asthma for the preceding 12 months were recorded, and attendents were asked of their daily consumption of cigarettes during the preceding 12 months. Weight and height were also recorded.

The Findings

Overall, Korppi and colleagues recorded 36 cases (62.0%) of previous asthma in childhood, compared to 12.0% of 100 controls (OR 12.0, 95%CI 5.38-26.8).

Early-childhood wheezing was associated with RSV infection in 14 (24.1%) and by rhinovirus infection in 10 (17.2%) of cases, with 5 RSV positive cases being were dual viral infections.

Investigators recorded 20 cases (34.5%) of wheezing symptoms compared to 14.0% of controls), and 28 cases (48.3%) versus 35.0% of controls reported symptoms of allergic rhinitis (OR 2.13).

There were no significant differences between cases and controls in reporting of prolonged cough, night cough or atopic dermatitis.

Weekly use of bronchodilators was more common (25.9%) in cases than in controls (7.0%, OR 4.6), as was inhaled corticosteroids during last 12 months.

Of the total number of participants in the cases group, 6 (10.3%) had doctor-diagnosed asthma compared to 5.0% of the controls (p=0.22), and the risk of self-reported asthma was 1.25-fold when early-childhood wheezing was associated.

Altogether, 31 subjects from both the case and control groups presented with self- reported asthma, all of whom differed from those 127 without self-reported asthma in the presence of previous asthma, current overweight (BMI >25) and symptomatic allergic rhinitis during the last 12 months.

“Against these worries, the detection rates of asthma were not higher than in other similar cohort studies in either cases or controls, and in addition, a participant of a questionnaire study does not receive any health care services,” the investigators wrote. “Since the main outcomes, doctor-diagnosed and self-reported adulthood asthma, were rather rare, the power of the study was not enough to reveal all available differences between the groups.”

The study, “An increased asthma risk continued until young adulthood after early- childhood hospitalisation for wheezing,” was published online in Acta Paediatrica.