Passive smoking harms teenager hearing

Passive smoking nearly doubles the risk of hearing loss among teenagers, a study found.

Living with someone who smokes has already been shown to increase the risk of dying from heart disease and lung cancer.

Second-hand smoke also makes asthma attacks worse and is a cause of middle ear infections. However, the latest study is the first to link passive smoking with hearing loss.

Researchers at New York University School of Medicine conducted hearing tests on more than 1,500 teenagers aged between 12 and 19. Exposure to second-hand smoke was determined by measuring the amount of cotine - a metabolite of nicotine - present in blood samples.

Teenagers exposed to second-hand smoke were more likely to have sensorineural hearing loss, which is most often caused by problems with the cochlea, the snail-shaped hearing organ of the inner ear.

"It's the type of hearing loss that usually tends to occur as one gets older, or among children born with congenital deafness," said Professor Michael Weitzman, a professor in paediatrics at the university and one of the study authors.

Overall, the study found that "tobacco smoke is independently associated with an almost two-fold increase in the risk of hearing loss among adolescents."

Teenagers exposed to second-hand smoke performed worse across every sound frequency tested, but mid-to-high frequency sound, important for understanding speech, was particularly affected.

Children with this type of mild hearing loss may have difficulties understanding what is being said in the classroom, which could lead them to become distracted. This could lead them to being labelled as disruptive or even misdiagnosed with attention deficit hyperactivity disorder, particularly as 8 out of 10 teens affected were unaware they had a hearing problem.

Professor Anil Lalwani, who led the study, said: "We need to evaluate how we deal with smoking in public places and at home, as well as how often and when we screen children for hearing loss."

He added that all children exposed to second-hand smoke should be regularly screened.

The study is published in the journal Archives of Otolaryngology – Head & Neck Surgery.

This article was published on Tue 19 July 2011