Passive cigarette smoke exposure in primary school children in Liverpool

OBJECTIVE: To assess environmental tobacco smoke (ETS) exposure amongst primary school children. METHODS: A descriptive, community-based, cross-sectional study of self-reported parental smoking patterns and children's salivary cotinine concentrations in 245 children aged 5-11 years attending 10 primary schools in Liverpool. RESULTS: The mean age was 7.4 years. The percentage of children living in smoking households was higher than the average reported for England (61.4% vs 53.0%). The average daily number of cigarettes smoked was similar for fathers (15.8) and mothers (16.4). The mean salivary cotinine concentration (+/-SD) was 1.6+/-0.4 ng/ml, and was higher in boys than girls (1.9+/-0.4 vs 1.2+/-0.2 ng/ml, P=0.006). The mean cotinine concentration was higher amongst children less than 7 years of age compared with older children (1.9+/-0.9 vs 1.4+/-0.6 ng/ml, P=0.01). Children from disadvantaged socio-economic households (Townsend score > + 6) had a mean cotinine level of 1.9+/-0.4 ng/ml, and a higher risk of a positive cotinine-validated level (>or=1 ng/ml) [crude odds ratio (OR) 3.5, 95% confidence interval (CI) 1.6-5.2). Maternal, but not paternal, cigarette smoke exposure was significantly associated with the salivary cotinine-validated level in children (adjusted OR 2.5, 95%CI 1.8-3.4). CONCLUSIONS: Maternal smoking, age less than 7 years, child's gender (male) and low socio-economic status were significant risk factors associated with ETS exposure in young school children in Liverpool. The level of childhood ETS exposure in this area demonstrates a major public health concern that creates a challenge for innovative interactive strategies