Pneumonia in infancy tied to childhood asthma

Asthma appears to be prevalent among children who developed pneumonia in infancy, as reported in a study.

The study used data from a nationwide register-based cohort involving 948,045 Swedish children. Researchers examined the potential relationship between pneumonia in infancy and prevalent asthma at 4 years of age, as well as the effect of nationwide pneumococcal conjugate vaccine (PCV) immunization on the association.

In the cohort, 23,086 (2.4 percent) children were diagnosed with pneumonia prior to 2 years of age. These children were more likely to be male, born prematurely, delivered via caesarean section, small for gestational age, born to mothers who smoked during pregnancy, and have comorbidities, among others, compared with those who did not have pneumonia.

A total of 60,565 (6.4 percent) children had prevalent asthma at 4 years, with the cumulative incidence being 11.6 percent during the study period. More children with vs without pneumonia in infancy had prevalent asthma at 4 years (18.9 percent vs 6.1 percent).

Pneumonia diagnosis in infancy was strongly associated with prevalent asthma at 4 years in the multivariable logistic regression analysis (adjusted odds ratio [OR], 3.38, 95 percent confidence interval [CI], 3.26–3.51), as well as in the full sibling analysis (adjusted OR, 2.81, 95 percent CI, 2.58–3.06).

The risk of asthma following pneumonia diagnosis in infancy was slightly higher among children born in the PCV period vs the pre-PCV period (adjusted OR, 3.80, 95 percent CI, 3.41–4.24 vs 3.28, 95 percent CI, 3.15–3.42).

Moreover, in the PCV vs the pre-PCV period, the proportion of viral pneumonia aetiology was also higher (14.5 percent vs 10.7 percent, respectively) while the overall asthma prevalence was lower (5.3 percent vs 6.6 percent).

The findings may inform future asthma preventive measures and should be considered when assessing the morbidity that can be attributed to pneumonia.