Secondhand Smoke Leaves Kids Prone to Severe Infections

And those infections force many children to be hospitalized, study finds

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By Amanda Gardner
HealthDay Reporter

WEDNESDAY, May 28 (HealthDay News) -- Here's another reason why adults shouldn't smoke around kids:

In addition to developing asthma and respiratory infections, children in households where someone smokes are more likely to catch a whole range of severe infections, including meningococcal disease. Many even have to be hospitalized, a new study found.

Being around smoke during the first few months of life was most dangerous, especially if the newborn was born underweight or premature.

"This is just adding to the list of why people should not be smoking," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City. "It's probably that smoking is not just a respiratory irritant, but many things in smoke affect the immune system."

The ill effects of secondhand smoke on people of all ages is well known. As more bans are put in place, children -- and others -- are exposed less and less to secondhand smoke in public places. But secondhand smoke in the home is another matter, according to the study authors, from the University of Hong Kong, whose findings are published online May 28 in the journal Tobacco Control.

The researchers followed 7,402 children born in Hong Kong in April and May of 1997 (representing almost 80 percent of all children born in Hong Kong during that time period) until they turned 8 in 2005.

Exposure to secondhand smoke within a distance of three meters (9.8 feet) in early life was associated with a 14 percent increased risk of being hospitalized for infectious diseases up until the age of 8.

And exposure to secondhand smoke during a baby's first six months of life increased the likelihood of a hospitalization by 45 percent by the time the child was 8. Babies born prematurely were twice as likely to be hospitalized, while those born with a low birth weight were 75 percent more likely to be hospitalized during the first eight years of life, the study found.

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."

More information

The American Lung Association has more on the effects of secondhand smoke on children.