Background: Secondhand tobacco smoke exposure impairs the control of pediatric asthma. Evidence of the efficacy of interventions to reduce children's exposure and improve disease outcomes has been inconclusive.
Methods: Caregivers of 519 children aged 3 to 12 years with asthma and reported smoke exposure attended two baseline assessment visits, which involved a parent interview, sampling of the children's urine (for cotinine assay), and spirometry (children≥5 years). The caregivers and children (n=352) with significant documented exposure (cotinine≥10 ng/mL) attended a basic asthma education session, provided a third urine sample, and were randomized to the Lowering Environmental Tobacco Smoke: LET'S Manage Asthma (LET'S) intervention (n=178) or usual care (n=174). LET'S included three in-person, stage-of-change-based counseling sessions plus three follow-up phone calls. Cotinine feedback was given at each in-person session. Follow-up visits at 6 and 12 months postrandomization repeated the baseline data collection. Multivariate regression analyses estimated the intervention effect on the natural logarithm of the cotinine to creatinine ratio (lnCCR), use of health-care services, and other outcomes.
Results: In the sample overall, the children in the LET'S intervention had lower follow-up lnCCR values compared with the children in usual care, but the group difference was not significant (β coefficient=-0.307, P=.064), and there was no group difference in the odds of having>one asthma-related medical visit (β coefficient=0.035, P=.78). However, children with high-risk asthma had statistically lower follow-up lnCCR values compared with children in usual care (β coefficient=-1.068, P=.006).
Conclusions: The LET'S intervention was not associated with a statistically significant reduction in tobacco smoke exposure or use of health-care services in the sample as a whole. However, it appeared effective in reducing exposure in children at high risk for subsequent exacerbations.
Trial registry: ClinicialTrials.gov; No.: NCT00217958; URL: clinicaltrials.gov.