Unintentional Tobacco Smoke Exposure in Children.

Secondhand smoke (SHS) exposure increases the prevalence and severity of sinopulmonary diseases in children. The primary source of SHS exposure in children is through adults who live in the same house; however, the level of exposure may vary based on the adult smoking habits at home. This prospective cross-sectional study in Alberta, Canada, investigated the relationship between self-reported caregiver smoking, location, outdoor temperature and children’s’ urine cotinine: creatinine ratio (CCR), a marker of nicotine metabolism. Participants aged 0−9 were recruited from the Child Health Clinics at the Misericordia Community Hospital in Edmonton, Alberta, from 8 January to 24 February 2016 and 30 June to 18 August 2016. Participant CCR levels were compared to caregiver-reported smoking location and environmental factors such as temperature and season. Of the 233 participants who reported smoking status, 21% reported smoking, in keeping with local smoking rates. More participants smoked indoors during the winter than the summer; however, some families limited indoor smoking to a garage. Of the 133 parent−child dyads who provided smoking information and a child urine sample, 18 had an elevated cotinine:creatinine ratio, suggestive of significant tobacco smoke exposure, 15 of whom were from homes that reported smoking. Age < 1 year and number of cigarettes smoked in the home weekly were risks for significant exposure while season, outdoor temperature and smoking location in the home did not reach significance. Smokers should be counseled to protect children, particularly infants, from exposure by limiting the number of cigarettes smoked and isolating smoking to outside the home. Segregated areas such as a garage may provide a useful harm mitigation strategy for indoor smokers, provided the garage does not share ventilation or is not in close proximity to high-traffic areas of the home.