Children exposed to secondhand smoke at home are more likely to carry the streptococcus pneumonia bacteria in their nose and throat, according to Israeli researchers.

A study involving more than 200 children and their mothers found that 76 percent of children exposed to secondhand smoke carried the bacteria in their noses and throats, compared to 60 percent of those not exposed to smoking. The bacteria can cause minor illnesses like ear infections or more dangerous conditions like sinusitis, pneumonia, and meningitis.

Among the mothers, 32 percent of smokers carried the bacteria, compared to 15 percent of nonsmokers exposed to tobacco smoke and 12 percent of nonsmokers not exposed to secondhand smoke.

"Since carriage in the nose is the first step in causing disease, the increased rate of carriage suggests more frequent occurrence of the disease. Indeed, active and passive smoking are associated with increased rate of respiratory infectious diseases," said lead study author David Greenberg, M.D. "This should definitely encourage the parents not to smoke in the presence of their child, especially if this child has predisposing factors such as asthma."

The study was published in the April 1, 2006 issue of the journal Clinical Infectious Diseases.