June 10, 2008
Smoking, Obesity Linked to Permanent Hearing Loss
A new study has found that obesity and smoking could be linked to permanent hearing loss.
Although scientists involved in the Antwerp University study noted that high levels of work-related noise remains the biggest risk, they added that both smoking and obesity could cause hearing loss by decreasing blood flow and oxygen to the ears.
The study was conducted jointly between the University of Paris and University College London.
This causes a build up of free radicals in cochlear tissue, causing damage, hair cell death and ultimately loss of hearing, scientists said.
Others have suggested such a link, but the most recent report, involving more than 4,000 men and women between the ages of 53 and 67, made the most solid conclusion to date.
Researchers found that people who smoke regularly for more than one year had worse hearing than those who had never smoked.
Additionally, they write, the more a person smoked, the greater their risk of hearing loss grew.
Scientists were able to gauge participants' level of damage by administering a hearing test. Each participant was also given a survey about his or her lifestyle.
Dr Erik Fransen, of the University of Antwerp in Belgium, one of the lead researchers, said that the ability to pick out high frequency sounds was damaged in smokers and the obese, although to not as great an extent as those exposed to very loud noise in the workplace.
"The hearing loss is proportional to how much you smoke and your body mass index (BMI)."
"It starts getting worse once you have smoked regularly for more than one year," Fransen said.
He said that, unlike some parts of the body, once damage had occurred, there was no prospect of recovery.
"Once the damage is done, it's done. It does not repair."
Dr Fransen said that both smoking and being obese decreases the flow of blood to organs in the body. The resulting lack of oxygen added with the failure to remove toxic waste from the ear can be damaging.
Amanda Sandford, from the pressure group Action on Smoking and Health (ASH), said that the results, published in the Journal of the Association for Research into Otolaryngology, should serve as a warning particularly to younger smokers.
"There are so many young people who think that they can give up in middle age and escape some of the other diseases associated with smoking."
"In this case, some of the damage may already have been done," Sandford said.
The study was part-funded by the Royal National Institute for the Deaf (RNID).
"This exciting new research shows that you're not just harming your heart and lungs when you have a cigarette "“ you could be putting your hearing at risk too," said Dr. Mark Downs, Executive Director of Technology and Enterprise at RNID.
"With an ageing population age-related hearing loss is something that we need to take seriously. Losing your hearing in later life can make it harder to maintain contact with friends and families and lead to isolation and/or depression "“ so making small concessions now could have an enormous effect in the long term."
"Making sure you keep your weight down and generally leading a healthy lifestyle is not only good for your heart but also good for your ears."
On the Net:
Association for Research into Otolaryngology