LAUSR

OBJECTIVE To objectively investigate the effect of passive smoking on pneumonia and disease severity in children aged less than 5 years by using cotinine as an indicator of passive smoking. METHODS Between December 2015 and April 2016, children aged less than 5 years with pneumonia and age-matched healthy controls were included in this study, which was conducted at three tertiary pediatric pulmonology centers. A questionnaire was given to the parents regarding demographic data and smoking status at home. Urinary cotinine/creatinine ratio (CCR) was measured. The data from the pneumonia and control groups, as well as children with mild and severe pneumonia within the pneumonia group, were compared. RESULTS A total of 227 subjects were included in the study; there were 74 children in the pneumonia group and 153 in the control group. The mean age of all the children was 33.4 ± 1.28 months. Of all subjects, 140 were male and 102 were exposed to passive smoking by their parents at home. There were statistically significant differences in age, number of people in the home, and mother's and father's age between the control and pneumonia groups (p < 0.05). No difference was found in the CCR in the control and pneumonia group (p > 0.05). Age and urinary CCR were significantly different between children with mild and severe pneumonia (p < 0.05). CONCLUSION We showed that passive smoking exposure was associated with the development of severe pneumonia in children. Further studies are needed to examine the underlying cause in detail.