Disparities in environmental factors
ETS – Previous studies have associated ETS with severe asthma and a decrease in the lung function of children with asthma42,43, however no studies evaluating the effect on outcome of these admitted children were conducted. Samir et al. did perform a retrospective study and showed a significant negative effect on LOS at the PICU of children admitted with a status asthmaticus who were ETS exposed and thus found an adverse outcome38. However, information on ETS exposure in this study was retrieved by parental information, which could implicate information bias.
Diet – Breastmilk has been associated with a positive effect on outcomes in pediatric health. Multiple studies have been performed that show a positive effect of breastmilk in the health of children with some respiratory diseases, that could be explained by the immunobiological components in breastmilk that can increase protection from respiratory diseases44,45. Additionally, Swathi et al, found a lesser mortality rate in infants with acute respiratory infection (ARI) admitted at the PICU that were exclusively breastfed in the first six months, but did not specify the causes of the ARI29. However, Leimanis Laurens et al. is the first study to find a contrary result and did not find any association between the diet and outcomes in infants admitted with a bronchiolitis at the PICU39, but had their data retrieved from a single study site; there was limited information about the quantities of the milk given and there was a difference of age between both groups.