The high rates of exposure "have significant public health implications," since secondhand smoke has been linked to growth, behavioral and mental deficits in children, along with a greater risk of sudden infant death syndrome, asthma and ear infections, according to Marie D. Cornelius, Ph.D., of the University of Pittsburgh and colleagues.
The mothers reported the number of cigarettes they smoked each day, the number of smokers in the house and the usual number of hours the children were exposed to secondhand smoke each day. The latter was most likely to correspond to levels of cotinine, a nicotine byproduct, in the children's urine, say the researchers.
Most of the children identified by their mothers as having secondhand smoke exposure also had detectable cotinine levels. But 10 percent of the group had very low cotinine levels, suggesting that their exposure could not have been confirmed by a urine test alone.
The researchers suggest that cotinine may not always be a reliable indicator of secondhand smoke exposure, since it can only be detected in the body a short time after exposure.
"For general screening purposes, the parent's report of the child's environmental tobacco exposure may identify more at-risk children," Cornelius says.
The study included 6-year-old children in 196 low-income families in Pittsburgh. More than 70 percent of the children lived in households with smokers, and mothers smoked in 59 percent of the families.
According to the mothers' reports, 85 percent of the children in the study had daily exposure to secondhand smoke. On average, the children experienced two and a half of hours of daily smoke exposure.
The study was supported by the National Institute on Drug Abuse.
BY BECKY HAM, STAFF WRITER
HEALTH BEHAVIOR NEWS SERVICE
FOR MORE INFORMATION
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Interviews: Contact Marie Cornelius at (412) 681-3482 or mdc1@pitt.edu.
Nicotine & Tobacco Research: Contact Gary E. Swan, Ph.D., at (650) 859-5322.
Journal
Nicotine & Tobacco Research