Healthnotes Newswire (February 1, 2001)—Children of parents who smoke are more likely to get recurrent ear infections than are children of nonsmoking parents, according to a study¹ published in the current issue of The Laryngoscope, a journal specializing in disorders of the ear, nose, and throat.

Researchers at the Otorhinolaryngology (ear, nose, and throat) Clinic of the Istanbul School of Medicine evaluated 114 children, aged 3 to 8 years, with middle ear infections and tympanostomy tubes (tubes surgically implanted in the eardrum under general anesthesia to drain the middle ear). They also observed 40 age-matched children who had no ear infections. Levels of cotinine were measured in the urine samples of all participating children. Cotinine is a byproduct of nicotine and is a well-accepted objective measurement of exposure to cigarette smoke.

In this study, 74% of the children with ear infections had urine levels of cotinine indicating exposure to secondhand smoke; by comparison, only 55% of the children without ear infections had cotinine levels this high. This difference was statistically significant.

These data demonstrate that exposure to secondhand smoke increases the risk of middle ear infections. The results of this study are consistent with most,^{2 3 4 5 6 7} though not all,^{8 9} previous studies examining this relationship. The authors of the current study noted that previous studies finding no association between secondhand smoke exposure and ear infections failed to use objective methods of analyzing exposure to cigarette smoke.

The new study also identified which family member had the most responsibility for the exposure. They found that maternal smoking appeared to have more of an effect on ear infections than did paternal smoking or smoking by other residents in the household, although this effect was not statistically significant. Moreover, these differences may be less relevant in the United States, where both parents in a household are often at work, than in Turkey, where the study was conducted.

It is not known precisely how cigarette smoke could cause ear infections. Secondhand smoke may damage the mucus membranes of the nose and throat that are responsible for clearing mucus from these passages. Decreased clearance of mucus from the nose and throat can block the eustachian tubes (tubes that drain the middle ear into the back of the throat). Cigarette smoke exposure can also cause the adenoids (lymph tissue at the back of the nose and throat) to become enlarged, further obstructing drainage of the eustachian tubes. Blockage of the eustachian tubes provides an environment in which infection-causing bacteria can thrive.¹⁰

Middle ear infections (otitis media) are among the most frequent illnesses of childhood. Ear infections can be mild annoyances, but if they are recurrent, they may also have damaging long-term effects, such as impaired language development, hearing, and communication skills;¹¹ permanent perforation of the eardrum; hearing loss; and cholesteatoma (a benign, though potentially damaging, tumor of the middle ear).¹²