Scientists think second-hand smoke affects the blood supply to the inner ear.
According to research, teenagers exposed to second-hand smoke are twice as likely to suffer hearing loss. The research findings add to the list of health problems already attributed to second-hand smoke, including increased risks of asthma, heart disease and lung cancer.
Teens exposed to second-hand smoke were more likely to have ‘sensorineural’ hearing loss, which is usually caused by problems with the cochlea, the snail-shaped hearing organ of the inner ear.
Scientists think passive smoking affects the blood supply to the area.
The damage caused makes it harder for the person to understand speech and has been linked to poor academic performance and disruptive behaviour in school.
Study author Dr Michael Weitzman, from New York University’s school of medicine, said: ‘It’s the type of hearing loss that usually tends to occur as one gets older, or among children born with congenital deafness.’
Dr Weitzman studied more than 1,500 teenagers aged 12 to 19. They were given extensive hearing tests along with 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 more likely to have sensorineural hearing loss than those who were not passive smokers.
Results of the study, published in journal Archives of Otolaryngology, which deals with head and neck surgery, also showed that more than four out of five affected were not aware of it.
Study co-author Dr Anil Lalwani, from the department of paediatrics at NYU’s school of medicine, 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.’
Via Daily Mail