Use of urinary cotinine and cotinine/creatinine ratio as a biomarker of environmental tobacco exposure

Abstract

Purpose: Exposure to Environmental Tobacco Smoke (ETS) remains a worldwide public health problem. The purpose of this study was to investigate the relationship between parents' smoking habits at home and children's exposure to environmental tobacco smoke by measuring urinary cotinine levels and urine cotinine/creatinine ratios in children.
 Materials and Methods: This case-control typed analytical study was conducted with 357 children in the 0-18 age group. The case group consisted of 180 children exposed to environmental cigarette smoke. As the control group, it consisted of 177 healthy children and non-smoking in their family. The levels of cotinine and creatinine in spot urinary were analyzed in both groups.
 Results: The urinary cotinine level of the children was found to be statistically higher in those whose parents were smokers, female gender, fathers with a low educational level, and those with 3 or fewer rooms in the house. The urinary cotinine/creatinine ratio of the children was found to be statistically higher in those whose parents were smokers (15.91 pg/mg (1.54-147.54) vs 7.90 pg/mg (1.29-68.52)), female gender (13.19 pg/mg (1.79-115.07) vs 10.45 pg/mg (1.29-147.54)). Urinary cotinine levels in the ETS exposed group were affected 1042 times more than in the ETS unexposed group [OR:1042,462, 95% CI (139.821.839-7772.246)]. 
 Conclusion: In the present study, urinary cotinine levels were found to be higher in children exposed to tobacco smoke than in children not exposed to tobacco smoke. In the light of these results, urinary cotinine can be used as a biomarker to evaluate exposure to ETS in children. Educating parents is essential to raising their awareness of exposure to ETS and teaching the right behaviors to protect children's health, especially in the home environment.