Overall, 17 percent of the children were readmitted to the hospital for asthma or wheezing within one year of their first admission. Of the children with complete tobacco exposure information, 35 percent had been exposed to tobacco smoke according to their caregivers. However, 56 percent of them had been exposed based on cotinine levels in their blood, and 80 percent of them had high enough cotinine exposures in their saliva to show they had been exposed at least secondhand to tobacco.
In fact, 39 percent of the children whose caregivers said children didn’t have tobacco exposure had cotinine detected in their blood. In addition, 70 percent of the children whose caregivers reported no tobacco exposure had cotinine detected in their saliva. The researchers did not find that children were more or less likely to be readmitted to the hospital if their caregiver had reported tobacco exposure, but the results differed for those with cotinine in their blood or saliva.
Children whose blood samples contained cotinine had 1.6 times greater odds of being admitted to the hospital again within a year of their first hospital visit, compared to children without cotinine levels in their blood. Children whose saliva samples contained cotinine had 2.4 times greater odds of readmission to the hospital for asthma or wheezing, compared to children without cotinine in their saliva.”We found that secondhand smoke exposure was common among children admitted for wheezing or asthma,” the researchers concluded.
They found that being readmitted to the hospital for asthma or wheezing was specifically linked to tobacco exposure detected by cotinine levels in the blood or saliva. However, parent or other caregiver reports of exposure to tobacco smoke for the child did not predict whether a child could expect to be readmitted to the hospital or not. Having children’s blood or saliva tested for levels of cotinine may therefore offer insights into whether the child’s asthma or wheezing may require later hospitalization.
This study was published January 20 in the journal Pediatrics. The authors reported no potential conflicts of interest. The research was funded by the National Institutes of Health, a Flight Attendance Medical Research Foundation Young Clinical Scientist Award and the National Institute of Environmental Health Sciences.