Is some deafness avoidable? Hearing loss is usually accepted as an unavoidable side effect of ageing, but new research suggests that lifestyle has a greater influence than previously thought.

According to the largest study on age-related hearing impairment done so far, the recipe for keen ears well into the senior years may be simple: stop smoking, stay slim, and have an alcoholic drink at least once a week.

“Our take-home message is that hearing loss up to a certain degree is preventable. Environmental factors are responsible for about 50% [of age-related deafness] and we now know which ones to avoid,” says Erik Fransen at the University of Antwerp in Belgium.

Fransen and collaborators in nine European countries analysed lifestyle questionnaires and hearing tests from 4000 people aged 53 to 67.


Dose-dependent link

Perhaps unsurprisingly, noise exposure, known to destroy the sound-transducing hair cells in the inner ear, was the biggest risk. More surprising is the apparent effect of smoking and overeating.

These factors have been suspected as potential causes of deafness, but it has been hard to separate them from the effects of cardiovascular diseases that are also frequently suffered by people who smoke and overeat. This study has been able to do just that.

“Since the current study is so large, we found enough otherwise healthy smokers to show a direct and dose-dependent link between smoking and bad hearing,” says Fransen. “For example, a 60-year-old man who has smoked a pack a day for at least 10 years loses about five decibels on top of the 25 dB loss experienced by a third of the people his age.”

Smoking and excess weight both decrease blood circulation, a cause of cardiovascular disease. But the inner ear itself is very sensitive to circulation problems, explains Fransen: “Hair cells die when they do not get enough oxygen and when toxic free radicals do not get transported away fast enough. Smoking also directly increases radical production, making matters worse.”

Incentive to quit

In contrast, the questionnaires suggested that moderate alcohol intake may protect hearing – at least one drink a week. This may occur through improved blood circulation, suggests Fransen.

Karen Cruickshanks at the School of Medicine and Public Health at the University of Wisconsin in Madison, US, says the study is exciting.

“For some people, finding out about the added risk of hearing loss might provide them with that extra incentive to quit smoking,” she says.

Journal Reference: Journal of the Association for Research in Otolaryngology (DOI: 10.1007/s10162-008-0123-1)