Loud Music

Have you thought about those teenagers who listen to loud music all the time might suffer milder hearing loss? On the car, they might turn up the stereo as loud as they can, I don't know why, maybe that is what everybody is doing, and they felt it so cool.
At home or going out with family, they always wearing those iPod headset, and they might turn the music loud again. Even you trying to talk to them, they might not hear you. With all of these, and a long duration of time, they might have a hearing loss symptom. That's one suggestion. Should we allow them to continue a lifestyle like this?