RNID research discovers genetic link to hearing loss caused by loud noise

Editor: It's become pretty common knowledge that loud noises seem to have different effects on different people - that a noise that damages the hearing of one person can leave the hearing of another totally unaffected. Scientists are starting to unravel those types of situations, as they discover a genetic relationship to noise induced hearing loss (NIHL)

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Scientists funded by RNID, the national charity for deaf and hard of hearing people, have discovered a genetic link between exposure to loud noise and hearing loss.

The breakthrough could revolutionise ways of treating and preventing noise-induced hearing loss. In the UK, over one million people are at risk from or have already experienced noise related hearing loss1.

The findings published today 2 identified three genes that influence the risk of developing noise-induced hearing loss, a condition which is irreversible. These genes play a role in recycling potassium in the inner ear - a process essential to normal hearing.

Exposure to loud noise has long been known to cause hearing loss and is a leading occupational hazard in many countries. However, it has been less clear why some people are much more susceptible to noise damage than others.

RNID funded this pioneering research at the University of Antwerp2. Professor Guy Van Camp, who led the research says: "The project tested the hearing of 1, 261 noise-exposed male workers from paper pulp mills and steel factories in Sweden. Genetic testing was then carried out on the 10% most susceptible and 10% most resistant workers. 79% of the people in this study had been exposed to noise for at least 20 years. Significant differences between susceptible and resistant workers were found in the sequence of 3 genes, KCNE1, KCNQ1 and KCNQ4.

He continues: "Further studies on KCNE1 show the version of the gene associated with increased risk to noise causes the encoded ion channel to open more rapidly than the normal version. This could affect the recycling of potassium making people with this version of the gene more sensitive to noise."

Dr Ralph Holme, RNID's Biomedical Research Manager says: "This is a very exciting breakthrough. One million people in the UK alone are at risk of developing noise-induced hearing loss. This discovery could revolutionise the way this common form of hearing loss is prevented and treated in the future."

Dr Mark Downs, Executive Director of Technology and Enterprise, says: "Any kind of hearing loss can have a significant effect on the quality of personal, social and professional lives. Most people don't realise how important their hearing is until they start to lose it. Everyday activities such as using a phone, talking to colleagues and joining in with a conversation with a group of friends can become difficult. RNID would advise people who are concerned about their hearing to take our five minute, confidential, telephone hearing check on 0845 600 55 55."

RNID successfully lobbied the Government for changes in legislation relating to noise at work which the charity believes is still one of the most underestimated workplace risks. Excessive noise in the workplace has caused an estimated half a million people living in Great Britain today to suffer hearing difficulties 3. Tighter Noise at Work regulations which came into force in April 2006 and 2008 for the leisure industry will provide improved protection for workers from hearing loss, one of Britain's most serious occupational diseases.

Britain's Biggest Sound Check is part of RNID's Breaking the Sound Barrier Campaign, a bold campaign which aims to change attitudes towards hearing loss and hearing aids. The campaign aims to reach out to the 4 million people in the UK4 who are losing their hearing but doing nothing about it.

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1 Health and Safety Executive

2 Professor Van Camp headed the research at the University of Antwerp and the findings were published today at 09.00 EDT / 14.00 BST in the journal 'Human Mutation' and on-line at www.wiley.com/humanmutation (external link)

3 Research carried out by the MRC in 97/98 showed that 509,000 people suffered from hearing difficulties as a result of exposure to noise at work, we estimate that current figures will remain consistent.