In the Journals

Secondhand smoke exposure increased hospital readmission rates in children with asthma

Secondhand smoke at home or in the car increased children’s risk of being readmitted to the hospital within a year of being admitted for asthma, according to recent study findings published in Pediatrics.

“Smoke exposure is common among children admitted for asthma and is linked to an increased risk of readmission,” Robert S. Kahn, MD, MPH, of the division of general and community pediatrics at Cincinnati Children’s Hospital told Infectious Diseases in Children. “Use the window of opportunity around an asthma admission to engage parents around potential sources of smoke exposure and, with empathy not finger wagging; explore strategies to eliminate that exposure.”

Robert S. Kahn

Kahnand colleagues evaluated 619 children aged 1 to 16 years admitted for asthma or bronchodilator-responsive wheezing to determine the effect of secondhand smoke on hospital readmission.

Serum and salivary cotinine levels were taken during the patients’ hospital stay and primary caregivers were questioned about tobacco exposure. Follow-up was conducted for 12 months to see whether patients were readmitted.

Thirty-five percent of caregivers reported that the patient was exposed to tobacco. Of those, 23.7% reported exposure in the primary residence, 12% in the secondary residence and 12.3% in the car. More than half of children had serum (56.1%) and salivary cotinine (79.6%) levels above the limit of detection.

Most children had detectable serum (87.6%) and salivary cotinine (97.7%) levels when they had reported exposure to secondhand smoke. Of children with no reported exposure, 39.1% had detectable serum and 69.9% had detectable salivary cotinine levels.

There was no significant difference of readmission rates between those with reported secondhand smoke and those with no reported secondhand smoke (P=.21). Patients with detectable serum cotinine levels had higher readmission rates compared with those without detectable rates (P=.03), and the same was true for detectable salivary cotinine levels compared with no detectable levels (P=.007).

Hospital readmission was not significantly predicted by caregiver reports of secondhand smoke (adjusted OR=1.23; 95% CI, 0.79-1.89). However, detectable serum (adjusted OR=1.59; 95% CI, 1.02-2.48) and salivary (adjusted OR=2.35; 95% CI, 1.22-4.55) cotinine levels were significantly associated with hospital readmission.

“The ability to measure serum and salivary cotinine levels presents the possibility of an objective measure that can be obtained when a child is seen in the emergency department or in the hospital and may be used to predict future hospitalizations,” Kahn said in a press release. “Such a measure for exposure to tobacco smoke could be used to target specific interventions at caregivers of those children before discharge from the hospital. Several interventions, including parental counseling and contact with the primary care physician, could be adopted in the clinical practice.”

Robert S. Kahn, MD, MPH, can be reached at

Disclosure: The study was funded in part by a Flight Attendant Medical Research Foundation Young Clinical Scientist Award and the NIH.