Urinary cotinine levels show high concordance with tobacco exposure and lower oxygen saturation in infants with community acquired lower respiratory system infection

Childhood pneumonia is an important issue causing morbidity and mortality especially in developing countries. Secondhand smoking has been shown to increase the risk of lower respiratory tract diseases, especially in children under 2 years of age. In epidemiological studies, secondhand smoking is evaluated mostly by measuring cotinine level in urine. The aim of this study is to determine the environmental tobacco exposure status of otherwise healthy infants who were admitted to the hospital due to community-acquired lower respiratory tract infection and to investigate the effects of environmental tobacco exposure on clinical parameters, laboratory findings and hospitalization periods. When daily household tobacco consumption and the distribution of cotinine was compared, greater consumption was found to be statistically significantly associated with cotinine elevation (n =115, p=0.001). No significant relationship was found between the likelihood of high cotinine levels and the proximity of tobacco consumption to the child (n=86, p = 0.501). Among all participants urinary cotinine elevation was significantly correlated with lower oxygen saturation levels (p = 0.038) at admission. In this study, it is shown that exposure from surfaces previously exposed to tobacco smoke (environmental tobacco exposure) is also an important parameter that affects infants’ clinical status and must be considered a negative prognostic factor during evaluation of an infant with community acquired lower respiratory system infection. It is imperative to create a strict smoke-free, tobacco exposure-free environment for improved infant health in the community.