Several risk factors have been associated with the prevalence of recurrent wheezing (RW) and its severity, especially viral respiratory infections and second-hand smoke (SHS) exposure.

A new study published in Allegologia et Immunopathologia analyzed the relationship between SHS exposure at home and wheezing in infants during their first year of life.

In this study, parents of infants from the city of Cordoba, Argentina, were invited to complete a standardized questionnaire, voluntarily and anonymously. Wheezing was classified as occasional wheezing (OW) when having one or two episodes during the first 12 months of life; recurrent wheezing (RW) if having three or more episodes during the first 12 months; and more frequent wheezing (MFW) if there were ≥6 episodesduring the first 12 months.

The results showed that 409 infants had one or more episodes of wheezing in the first 12 months. Of these, 52.3%presented with occasional wheezing (OW), 33% had recurrent wheezing (RW)and14.7% more frequent wheezing (MFW). Meanwhile, SHS was significantly related to MFW, especially if the mother smoked or if she had smoked during pregnancy. This group of MFW was also associated with SHS, as well as having been to the emergency room for wheezing.

Therefore, it was concluded that second-hand tobacco smoke is a significant risk factor for the presence of wheezing in infants and for its severity.