Airway symptoms and atopy in young children prescribed asthma medications: A large-scale cohort study

Trends in childhood asthma in Denmark, Finland, Norway and Sweden

AIM

Estimate the incidence of asthma among children aged 0 to 15 years in Denmark, Finland, Norway and Sweden during 2000-2017.

METHODS

Cases of preschool asthma (up to 6 years) and school-age asthma (from 6 years) were identified through national registers using an algorithm including hospital diagnoses and prescription medicines. The respective cumulative incidence (CI) was estimated in 1-year age intervals for each country and birth year.

RESULTS

The CI of algorithm-based preschool asthma peaked for the birth cohorts 2008 or 2009 at 14.8% in Denmark, 11.0% in Finland, 15.1% in Norway and 13.7% in Sweden. For later birth cohorts, a slight decrease was observed. The CI of school-age asthma was 7.1% in Denmark, 10.5% in Finland, 9.7% in Norway and 10.2% in Sweden (children born in 2002). A slight decline over time was seen in Denmark and Norway, and a slight increase in Sweden and Finland.

CONCLUSION

Finland had a markedly lower CI of preschool asthma and Denmark lower CI of school-age asthma as estimated by prescriptions and hospital diagnoses. Preschool asthma may have plateaued in the Nordic countries. For school-age asthma trends over time varied by country. Differences in diagnostic and prescription practices may have influenced the results.

Small airway dysfunction is an independent dimension of wheezing disease in preschool children

BACKGROUND

Whether small airway dysfunction (SAD), which is prevalent in asthma, helps to characterize wheezing phenotypes is undetermined. The objective was to assess whether SAD parameters obtained from impedance measurement and asthma probability are linked.

METHODS

One hundred and thirty-nine preschool children (mean age 4.7 years, 68% boys) suffering from recurrent wheezing underwent impulse oscillometry that allowed calculating peripheral resistance and compliance of the respiratory system (markers of SAD) using the extended RIC model (central and peripheral resistance, inertance, and peripheral compliance). Children were classified using the probability-based approach of GINA guidelines (few, some, and most having asthma). A principal component analysis (PCA) that determined the dimensions of wheezing disease evaluated the links between SAD and asthma probability.

RESULTS

Forty-seven children belonged to the few, 28 to the some, and 64 to the most having asthma groups. Whereas their anthropometrics and measured parameters were similar, the most having asthma group exhibited the lowest mean value of airway inertance after bronchodilator probably due to airway inhomogeneities. PCA characterized four independent dimensions including a peripheral resistance (constituted by baseline peripheral compliance, Frs, R5Hz, R5-20Hz, X5Hz, and AX), a central resistance (baseline central resistance, R20Hz), anthropometrics (age and height), and asthma probability (wheezing patterns and therapeutic steps). Thus, PCA showed that the SAD markers were independent from clinical dimensions and were unable to differentiate wheezing phenotypes.

CONCLUSIONS

Lung function parameters obtained from impulse oscillometry and asthma probability were belonging to independent dimensions of the wheezing disease.

Preschool Wheezing: Trajectories and Long-Term Treatment

Wheezing is very common in infancy affecting one in three children during the first 3 years of life. Several wheeze phenotypes have been identified and most rely on temporal pattern of symptoms. Assessing the risk of asthma development is difficult. Factors predisposing to onset and persistence of wheezing such as breastfeeding, atopy, indoor allergen exposure, environmental tobacco smoke and viral infections are analyzed. Inhaled corticosteroids are recommended as first choice of controller treatment in all preschool children irrespective of phenotype, but they are particularly beneficial in terms of fewer exacerbations in atopic children. Other therapeutic options include the addition of montelukast or the intermittent use of inhaled corticosteroids. Overuse of inhaled steroids must be avoided. Therefore, adherence to treatment and correct administration of the medications need to be checked at every visit.