(RxWiki News) Secondhand smoke can cause asthma to flare up, especially in children. Knowing a child's history of tobacco exposure may help pediatricians spot who is at risk for future asthma attacks.
A recent study found that tobacco exposure from secondhand smoke was common among children in the hospital who were admitted for asthma or wheezing.
The researchers discovered that blood and saliva samples confirming tobacco exposure were associated with readmission to the hospital within one year.
"Keep your child away from tobacco smoke."
The lead author of this study was Robert S. Kahn, MD, MPH, from the Division of General and Community Pediatrics in the Department of Pediatrics of the Cincinnati Children's Hospital in Cincinnati, Ohio.
The study included 619 children from a previous study called the Greater Cincinnati Asthma Risk Study who were admitted to the Cincinnati Children's Hospital Medical Center between August 2010 and October 2011 for asthma or wheezing.
All the participants of the current study were between the ages of 1 and 16 years old, with the average age being 6 years old. A total of 57 percent of participants were African-American, and 65 percent were male.
The researchers assessed the children's tobacco exposure by asking the participants' primary caregivers if anyone smoked regularly in the car or in their primary and/or secondary residence.
Blood and saliva samples were collected from the participants within an average of 23 hours after hospital admittance. The researchers measured the amount of cotinine — what nicotine becomes when broken down inside the body — in each of these samples.
Information on the primary caregivers, such as education level and annual household income, was also recorded.
The findings showed that 17 percent of the participants were readmitted to the hospital after one year.
A total of 35 percent of the participants had a primary caregiver report tobacco exposure, with 24 percent reporting exposure in the primary residence and 12 percent reporting exposure in a secondary residence.
A total of 56 percent of the participants had detectable cotinine (confirmed tobacco exposure) in their blood samples, and 80 percent showed tobacco exposure in their saliva samples.
The children with detectable cotinine in their blood were 59 percent more likely to be readmitted to the hospital within a year compared to those with no detectable cotinine in their blood.
Compared to the children with no detectable cotinine in their saliva, those with detectable cotinine in their saliva were 2.35 times more likely to be readmitted to the hospital within a year.
The findings revealed that among the children whose primary caregivers reported no tobacco exposure, 39 percent had detectable cotinine in their blood, and 70 percent had detectable cotinine in their saliva.
A total of 99 percent of the children with caregivers who reported tobacco exposure had detectable cotinine in their blood, and 98 percent had detectable cotinine in their saliva.
African-American children accounted for 61 percent of the participants who had detectable cotinine in their blood and 87 percent of the participants who had detectable cotinine in their saliva.
Lastly, the researchers discovered that 72 percent of the children in households where the annual income was less than $15,000 per year had detectable cotinine in their blood, compared to 11 percent of the children in households where the annual income was more than $90,000 per year.
The authors mentioned a few limitations of their study. First, hospital admission data was only available for the Cincinnati Children's Hospital Medical Center and the participants may have been admitted at another hospital. Second, the data did not include visits to the emergency room or immediate care centers. Third, the study population was mostly made up of white and African-American participants, so the findings may not be applicable to the general population. Fourth, tobacco exposure may have been associated with variables not considered in the study. Lastly, the researchers did not have information on the participants' asthma medication.
This study was published on January 20 in Pediatrics.
The National Institutes of Health, the Flight Attendant Medical Research Foundation and the National Institute of Environmental Health Sciences provided funding.