Alert! More than a billion young people are hearing or impaired. Do you have these habits?

Around 1 billion young people worldwide could be at risk of hearing loss from listening to headphones or attending loud music venues, a large review of the available research estimated on Nov 15.

The study, led by the World Health Organization (WHO), called on young people to be more careful about their listening habits, and urged governments and manufacturers to do more to protect future hearing.

The analysis published in the journal BMJ Global Health looked at data from 33 studies published in English, Spanish, French and Russian over the last two decades covering more than 19,000 participants aged between 12-34.

Two Bad Habits That Affect Your Hearing

It found that 24 percent of the young people had unsafe listening practices while using headphones with devices such as smartphones. And 48 percent were found to have been exposed to unsafe noise levels at entertainment venues such as concerts or nightclubs.

Combining these findings, the study estimated that between 670,000 to 1.35 billion young people could be at risk of hearing loss.

Some young people are probably at risk from both factors, said Lauren Dillard, an audiologist at the Medical University of South Carolina and the study's first author.

Exposure to sound at too high a volume can fatigue the sensory cells and structures in the ear, Dillard said. If that goes on for too long, they can become permanently damaged, resulting in hearing loss, tinnitus or both.

Plugged into a smartphone downloaded with MP3 audio files, listeners often choose volumes as high as 105 decibels, and venues often range from 104 to 112 decibels, the study said. But the maximum safe volume recommended by experts is 80 decibels for adults and 75 decibels for children.

How to protect hearing?

Dillard said the best way for people to lessen their risk of hearing loss from headphones is to turn down the volume and listen for shorter periods. And headphone users should use settings or apps on smartphones to monitor sound levels, Dillard advised.

Experts cannot conclusively say which headphones are the safest for listening, Dillard said, but she did recommend using ones that reduce background noise. In loud environments, noise-canceling headphones can help avoid "cranking up your music to try to drown out all that background noise," she said.

Earplugs should be worn at loud events like concerts or nightclubs, she said, adding, "Maybe it's fun to be in the front by the speakers, but it's not a good idea for your long-term health. All of these behaviors, these exposures can compound over the course of your entire life, and then when you're 67 years old, it can have a pretty big impact," she said.

Dillard called on governments to comply with WHO guidelines on safe listening, including making sure venues monitor and limit music levels. She also urged companies that make devices like phones to warn listeners when the volume is too loud, and to include parental locks to restrict children's exposure.

“Hearing is the sense that connects us to the people we love,” Swanepoel said in an email. “Taking care of our hearing is key to maintaining healthy relationship(s) and general health and well-being. Primary prevention in early adults is critical to avoid earlier onset and accelerated age-related hearing loss.”