More than one billion teenagers and young adults around the world are at risk of damaging their hearing as a result of listening to music that is too loud, the World Health Organization (WHO) has warned.

According to the WHO, 1.1 billion young people are at risk of hearing loss as a result of listening to music that is too loud on personal audio devices, such as iPods and smartphones, and attending noisy entertainment venues such as nightclubs and sporting events.

Data analysed by the WHO found that in middle-income and high-income countries, almost half of young people aged between 12 and 35 are exposed to unsafe sound levels from personal audio devices, while four in 10 are exposed to unsafe levels in entertainment venues.

Safe listening depends on the loudness of sound and the frequency of listening. For example, unsafe sound levels include exposure to 85 decibels (dB) for eight hours or 100dB for 15 minutes.

People who are exposed to loud sounds can develop temporary hearing loss or tinnitus - a ringing/noise sensation in the ears. If these sounds are particularly loud, regular or prolonged, hearing damage can become permanent.

"As they go about their daily lives doing what they enjoy, more and more young people are placing themselves at risk of hearing loss. They should be aware that once you lose your hearing, it won't come back. Taking simple preventive actions will allow people to continue to enjoy themselves without putting their hearing at risk," commented Dr Etienne Krug of the WHO.

The WHO recommends that in workplaces such as bars and nightclubs, people should not be exposed to more than 85dB up to a maximum of eight hours per day. However, it pointed out that patrons and staff in some of these venues are often exposed to even higher levels of noise. In many venues, noise levels reach 100dB and this is safe for no more than 15 minutes.

The WHO is urging teenagers and young people to lower the volume on their personal audio devices and wear earplugs when visiting noisy venues.

"They can also limit the time spent engaged in noisy activities by taking short listening breaks and restricting the daily use of personal audio devices to less than one hour. With the help of smartphone apps, they can monitor safe listening levels. In addition they should heed the warning signs of hearing loss and get regular hearing check-ups," it said.

The WHO is also calling on governments to develop and enforce strict legislation on recreational noise, and to raise awareness of this issue via public health campaigns.

It noted that some 360 million people worldwide have a moderate to profound hearing loss due to a range of causes, including genetic conditions, birth complications, ageing and noise. However, an estimated 50% of all of these cases are considered avoidable.