Cigarette fumes breathed in by children can damage their ears, a study has revealed.
Passive smoking was linked to “an almost two-fold increase in the risk of hearing loss” scientists found.
The degree of deafness was mild but potentially enough to affect how much they pick up in the classroom.
The US study looked at more than 1,500 children and teenagers aged 12 to 19.
Their hearing was tested and blood was analysed for traces of cotinine, a chemical the body produces from nicotine.
Cotinine in a non-smoker’s blood is evidence of passive smoking.
Those exposed to second-hand fumes were more likely to be suffering from senso-neural hearing loss caused by problems affecting the inner ear, said the study published in Archives of Otolaryngology – Head & Neck Surgery.
New York University’s Prof Michael Weitzman said: “It’s the type of hearing loss that usually occurs as one gets older or among children with congenital deafness.”