20% of US teens suffer from some type of hearing impairment

"Are ear buds bad for your hearing? Researchers aren't prepared to say a definitive "yes," but evidence is mounting.
A new national study has found that 1 in 5 adolescents now suffers some sort of hearing impairment. A likely culprit: a combination of ear buds and loud music.
In the Aug. 18 issue of the Journal of the American Medical Association, researchers from the Brigham and Women's Hospital in Boston analyzed federal data collected from national yearly surveys of the health of American citizens.
They looked at the prevalence of hearing loss among U.S. adolescents between 1988 and 1994 and compared that with the prevalence of hearing loss between 2005 and 2006. They found a 31 percent increase in hearing loss among those between 12 and 19 years old. Researchers say this means 1 in 5 adolescents now suffers some sort of hearing impairment.
While the hearing loss is described as only slight or mild, earlier studies have found that even mild hearing loss can negatively affect academic achievement and social interaction."
Source:  Data from the Journal of the American Medical Association, reported by NPR, 17th August 2010