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.

He said: “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.”

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.”