‘Passive smoking may cause hearing loss in teenagers’

According to the scientists,passive smoking affects the blood supply to the area which makes it harder for the person to understand speech and has been linked to poor academic performance and disruptive behaviour in school.

“It’s the type of hearing loss that usually tends to occur as one gets older or among children born with congenital deafness,” said Dr Michael Weitzman,who led the study.

The findings add to the catalogue of health problems already attributed to second-hand smoke,including increased risks of asthma,heart disease and lung cancer,the Daily Mail reported.

For the study,the researchers carried out extensive hearing tests of the teenagers. They were also given blood tests for the chemical cotinine,a substance produced when the body breaks down nicotine.

Those teens exposed to second-hand smoke,as measured by cotinine in their blood,were found to have sensorineural hearing loss than those who were not passive smokers.

Results of the study,published in journal Archives of Otolaryngology,also showed that about 80 per cent of those affected were not aware of it.

Study co-author Dr Anil Lalwani said: “More than half of all children in the U.S. are exposed to second-hand smoke,so our finding has huge public health implications.”

He added: “Milder hearing loss is not necessarily noticeable. Thus,simply asking someone whether they think they have hearing loss is insufficient.”

Dr Weitzman added: “The consequences of mild hearing loss are subtle yet serious.

“Affected children can have difficulty understanding what is being said in the classroom and become distracted. As a result,they may be labelled as troublemakers or misdiagnosed with ADHD.”