Lung function measurements in children - copsac

who do not develop RSV bronchiolitis. The risk factors for neonatal lung function was studied in
the COPSAC cohort in a recent publication (29) and showed that high body mass index in newborns
and mothers smoking were associated with reduced lung function, also that parental atopic
disease (mother’s or father’s eczema, urticaria or allergic rhinitis or father’s asthma) did not affect
the neonatal lung function and bronchial responsiveness.
In our study group of infants less than 2 years of age the mean age of the infants diagnosed with
RSV bronchiolitis was 8 months (30), which is higher than reported by other study groups. Other
studies have limited the group of interest to children less than 12 months of age and accordingly
reported even lower age of RSV infection (35, 62-65).
The incidence of bronchiolits (5%) was higher reported in most studies (1-3%) (5-7, 48, 66, 67).
This suggests a genetic component in RSV bronchiolitis as all mothers had asthma. Predisposition
to asthma and atopy has been associated with increased risk of lower respiratory tract infection and
hospitalization for RSV infection (64, 68, 69). Young et al (1995) found 7% of a cohort (253 infants)
with the diagnosis of bronchiolitis before 2 years of age (only 2 infants were hospitalized and
confirmed for RSV infection); 71% had a family history of atopy (18). A twin cohort study showed
that the severity of RSV infection was determined partly by genetic factors (16%); family environment
accounted for 73% and nonshared environment for 11% of the individual susceptibility to develop
severe respiratory syncytial virus infection (70, 71). A Danish case-control study has also
supported that asthmatic disposition and wheezing were strong determinants of subsequent respiratory
syncytial virus hospitalization in children