Smoke leads to teen hearing loss

Secondhand Smoke Associated with Hearing Loss in Teens
By Meredith Melnick

It's not news that second-hand smoke can be dangerous—even deadly. Now add one more price nonsmokers pay for living around people who light up: According to a new study from New York University's Langone Medical Center, teens who are regularly exposed to second hand smoke are nearly twice as likely to have hearing loss as teens who live in smoke-free environments.

The study involved 1,533 non-smoking adolescents between the ages of 12 and 19 who underwent hearing tests to determine auditory acuity at both high- and low-frequencies. Researchers also measured the subjects' blood concentrations of cotinine — a byproduct of the neurotoxin nicotine that is often used as a biomarker of smoke exposure.


Not only were teens who had the highest level of cotinine more likely to have high- and low-frequency hearing loss, the degree of that impairment was proportional to the level of blood toxicity. In other words, the greater the smoke exposure, the greater the damage — which suggests that the rate of hearing loss could be cumulative.


"Prior work has shown an association between secondhand smoke and ear infection in children which can be associated with conductive hearing loss that is reversible. In adults, smoking has been associated with early hearing loss," says lead author, Dr. Anil K Lalwani, a professor in the departments of Otolaryngology, Physiology and Neuroscience and Pediatrics at NYU Langone Medical Center. "I was concerned that secondhand smoke could similarly be injurious to children and cause injury to the inner ear leading to permanent sensorineural hearing loss."


But even with this suspicion and the evidence provided by the study, it's too early to say with certainty how secondhand smoke could relate to hearing loss. As Lalwani says, previous studies have established a link between smoke exposure and ear infections in children. When that exposure is chronic, the infections could be too, and hearing loss could result. For now, that mechanism is only theorized and more work will be needed to establish it conclusively.


Still, with up to 50% of American kids exposed to second-hand smoke either in the home or out in the world, it makes less sense than ever for smokers to keep lighting up. "In homes where there is active smoking, parents and caretakers should be made aware of risks to hearing in their children," wrote the researchers. Adults unwilling to safeguard their own health might at least take steps to look after that of their kids.


The study was published in the medical journal, Archives of Otolaryngology -- Head and Neck Surgery.