Boys have been more likely than girls to show signs of a particular type of hearing loss, but girls are catching up - and the ubiquity of portable audio players may be to blame, new research suggests.
Hearing tests conducted on a national sample of teenage girls and boys showed that now roughly 17 percent - or 1 in 6 - of teens of both sexes have hearing losses that can make it harder for them to hear speech and some high-pitched sounds.
"The girls have kind of just caught up with boys," study author Elisabeth Henderson of Harvard Medical School in Boston told Reuters Health. The study, published today in Pediatrics, didn't determine the cause of the hearing loss in girls, but one possibility, Henderson suggested, is that they are getting exposed to more loud noises.
Traditionally, boys were more likely to be exposed to loud noises from leaf-blowers, firearms, or work machines, Henderson noted - but today, more and more teens have portable music players, and both sexes are listening to loud music from headphones.
Indeed, the authors found that the percentage of teens who said they had listened to loud music through headphones in the last 24 hours increased from 20 percent in the late 1980s and early 1990s to 35 percent in more recent years.
The kids who reported recent exposures were no more likely to show signs of hearing loss, but it's still possible that this increase in portable loud music is having an effect, perhaps explaining why girls have caught up to boys' levels of hearing loss, Henderson said in an interview.
"We're seeing a lot more kids being exposed to music recreationally," she noted. To investigate whether the recent popularity of portable music players is affecting teens' hearing, Henderson and her colleagues looked at hearing tests collected from 2,519 teenagers between 1988 and 1994, and 1,791 teenagers between 2005 and 2006.
They considered three types of hearing loss: low-frequency loss, in which people struggle to hear sounds in the low end of the sound spectrum (such as parts of human speech); high-frequency hearing loss, which affects how well they hear high pitches (such as chimes or a microwave beep, or even kids' speech); and noise-induced hearing-threshold shifts, or "NITSs," in which people have trouble hearing sounds in the middle of the sound spectrum (which can include some human speech and higher-pitched sounds from musical instruments).
The investigators found that all three types of hearing loss were generally as common in the recent group of teens as they had been during the previous survey.