Loud music isn't the only cause of hearing loss among teenagers. A U.S. study found that adolescents exposed to second-hand tobacco smoke also face an elevated risk of impaired hearing.
"Second-hand smoke is incredibly toxic," said lead researcher Anil Lalwani, a professor in the departments of otolaryngology and pediatrics at New York University's school of medicine.
Indeed, this new study adds one more reason to avoid other people's fumes. Living with a smoker increases the odds of dying from cancer and heart disease. And, in children, smoke exposure is also associated with developmental and behavioural problems.
The latest findings, published in the journal Archives of Otolaryngology – Head & Neck Surgery, are based on 1,533 people, aged 12 to 19, who participated in the U.S. National Health and Nutrition Examination Survey. The survey gathered information on children, teens and adults across the United States.
As part of the survey, the participants underwent extensive hearing tests and were given blood tests for cotinine, a byproduct of nicotine exposure.
The results revealed that those with the highest levels of smoke exposure were the ones most likely to show signs of hearing loss, both in low and high frequencies. Based on earlier studies, the new results seem to make sense. Research has already shown that smokers suffer from premature hearing loss.
Dr. Lalwani speculated that second-hand smoke could lead to hearing loss by reducing the amount of oxygen-rich blood reaching the delicate structures of the inner ear. "Tobacco smoke is known to have a bad effect on blood vessels … and the inner ear is incredibly sensitive to blood flow," he said.
Hearing impairment could lead to other problems and may partly explain why second-hand smoke is also linked to behavioural issues, Dr, Lalwani said. For instance, if students can't hear properly, they may have a hard time learning their lessons and become easily distracted. As a consequence, they may be labelled as "troublemakers" or misdiagnosed with attention deficit disorder.
To complicate matters, more than 80 per cent of the affected teens didn't even know they had a hearing problem, according to the study. Dr. Lalwani noted that various health organizations recommend infants and young children be screened for hearing deficits. But there are currently no standardized procedures to check for problems later in childhood or adolescence. He thinks screening for hearing loss should be routinely done for older kids and teens.