Children born to younger, poorer mothers were more likely to be exposed to secondhand smoke.
"The major strength of the study is that it was done in Hong Kong where they can follow 80-plus percent of a birth cohort," said Dr. Norman Edelman, chief medical officer of the American Lung Association. "The respiratory findings are not new, the other infections are."
The study authors speculate that secondhand smoke may affect the immune system, making infants, toddlers and young children more susceptible to infections of all kinds.
"It suggests that [secondhand smoke] affects the infant's immune system in some way," said Dr. John Saito, an assistant professor of pediatrics at Texas A&M Health Science Center College of Medicine.
"The take-home message is that there is a distance factor here. If you are a certain distance away, it certainly reduces your child's risk," added Saito, who is chief of pediatric pulmonary, allergy and immunology and director of the Cystic Fibrosis Center at Scott & White Hospital, in Texas. "So while we have a very difficult time getting people to quit for a long period of time or at all, the message is that even if you can't manage to quit, just the fact that you can smoke outside or in the next room or just limiting the exposure significantly reduces the chance of your child getting an infection or being hospitalized, at least based on this study."
The American Lung Association has more on the effects of secondhand smoke on children.
SOURCES: Len Horovitz, M.D., pulmonary specialist, Lenox Hill Hospital, New York City; John Saito, M.D., assistant professor, pediatrics, Texas A&M Health Science Center College of Medicine, and
All rights reserved