A new scientific study conducted jointly by the University of Miami and Florida International University say that passive smokers are at a greater risk of hearing loss.

According to the researchers, tobacco smoke blocks the blood flow to the ear vessels disrupting the oxygen intake of the organ. Lack of oxygen causes toxic residue in the ear triggering hearing loss. However, doctors do not know the amount of cigarette smoke that causes hearing loss.

“We really do not know exactly how much smoke you need to be exposed to in order to be at increased risk. But we do know that the threshold for damage is very low. Really, the safe level of exposure is no exposure,” Dr David Fabry, who led the research said.

The researchers have studied hearing test results of 3,307 non-smokers to arrive at this result. The participants in the study were given a hearing test at three sound frequencies - high, medium and low. The study revealed that passive smokers are more prone to hearing loss compared to others. They could not decipher a conversation when there is another sound in the background.

Researchers around the world are aware of the effects of smoking. There was a study conducted by the University of Paris and University College London on the relation between smoking and hearing loss. However, this study finding published in the Journal Tobacco Control has taken the medical community by surprise.

"We already knew from our own research that regular active smoking is a significant risk factor leading to hearing loss and this new study is important as it highlights the increased risks posed by passive smoking too,” Dr Ralph Holme, head of biomedical research at the RNID (Royal National Institute for Deaf People), said.