Secondhand tobacco smoke in children with asthma: sources of and parental perceptions about exposure in children and parental readiness to change

Abstract

Background: Secondhand smoke triggers childhood asthma. Understanding sources of exposure, parental beliefs about exposure, and readiness to change that exposure are important for designing smoke exposure reduction interventions.

Methods: As part of screening for a clinical trial of a smoke exposure reduction intervention, 519 smoke-exposed children 3 to 12 years old with asthma provided urine specimens for cotinine testing, and their primary caregivers completed questionnaires.

Results: The urine cotinine to creatinine ratio (CCR) was lowest if neither the primary caregiver nor day-care provider smoked (mean CCR, 14.0; SD, 14.4), greater if either smoked (mean CCR, 22.2; SD, 21.3; and mean, CCR, 26.3; SD, 22.2, respectively), and greatest if both smoked (mean CCR, 39.6; SD, 27.5; p < 0.01). Parental perception of their child's exposure was weakly associated with the child's CCR (r(2) = 0.11, p < 0.001). Most parents (58.3%) reported that tobacco smoke exposure had small/no negative effect on their child's asthma. Substantial proportions of those for whom a specific exposure reduction action was relevant were classified as contemplating, preparing, or had recently taken action to reduce their child's exposure, including smoking cessation (61.3%), keeping the child out of smoke-exposed places (72.7%), and making the child's home (49.2%) and areas out of the home smoke free (66.9%).

Conclusions: Smoking by the primary caregiver and day-care provider are important sources of exposure for children with asthma. Parental assessment of their child's exposure is associated with biologically confirmed exposure but cannot be relied on to assess that exposure. Although the harm of smoke exposure was frequently underestimated, many parents appeared receptive to considering action to reduce their child's exposure.

Trial registration: (Clinicaltrials.gov). Identifier: NCT00217958.

Figures

Figure 1

Recruitment process results. *From administrative data: age 3 to 12 years, Kaiser Permamente member for ≥ 1 year, one or more asthma care visits in prior year, and met one of the following three criteria suggesting persistent asthma: physician diagnosis code of persistent asthma (based on 1997 National Asthma Education and Prevention Program guidelines4), or pharmacy records documenting four or more β-agonist dispensing events in prior year or four or more antiinflammatory asthma controller medication dispensing events in prior year, and physician-approved recruitment of the family. †The analysis sample (N = 519) represents 45.7% of the known eligible children.

Figure 2

Mean sCCR associated with parent's perception of their child's exposure to tobacco smoke. *Assessed by the question, “On a typical day, how much tobacco smoke do you think (child's name) is actually exposed to considering all locations?” Data are missing for four subjects. †Overall difference in means is significant at p