Teens are losing their hearing, study shows

Adolescent hearing declined significantly over almost two decades, according to two US surveys, which indicated about a 30 percent increase in the prevalence of hearing loss.

Poor hearing among adolescents can be common due to infection, genetics, complications during pregnancy and premature birth, ototoxic medications or head trauma, researchers said.

Although many have suggested factors such as exposure to loud noises such as music — particularly important in adolescents — or firearms, the exact mechanism for acquired hearing loss is not well understood.

Poor hearing among adolescents and younger children can negatively affect speech, learning, social skills and self-image.

"Hearing loss is a real concern and has been brought up many times… for public education to protect our young against noise-induced hearing loss,” said Dr. Samuel Yeak, head and senior consultant of the Department of Otorhinolaryngology at Tan Tock Seng Hospital in Singapore. However, he added that large-scale epidemiological data is unavailable in Singapore.

However, Dr. Low Wong Kein, a senior consultant in the Department of Otolaryngology at Singapore General Hospital, did point to a local study on a single cohort of Singaporean military conscripts that showed hearing loss prevalence of almost 40 in 1,000, particularly in those who were exposed to loud noise. [Singapore Med J 2002;43:622-7]

“Given the similarities in lifestyle, I believe this trend also applies in Singapore,” Low said.

Researchers from Brigham and Women’s hospital in Boston, Massachusetts, US, examined data on 1,771 adolescents aged 12 to 19 from the US, who participated in the Third National Health and Nutrition Examination Survey (NHANES III) between 1988 and 1994, and the NHANES conducted between 2005 and 2006. [JAMA 2010;304(7):772-778]

The cross-sectional analysis showed that the prevalence of hearing loss increased 31 percent (P=0.02) to 19.5 percent in 2005-2006 from 14.9 percent in 1988-1994.

Participants were classified according to whether hearing loss was in one or both ears and whether hearing was worse for low or high tones.

Loss of high frequency hearing in one ear was most common in all participants but these rates were highest among participants in the 2005-2006 survey.

The survey noted whether participants had more than three ear infections, exposure to firearm use and exposure to loud noise such as music for more than 5 hours per week, but these were not significantly associated with hearing loss for NHANES 2005-2006 respondents.

Poverty was a significant risk factor for hearing loss, however, and the prevalence among poorer individuals was 23.6 percent compared to 18.4 percent among wealthier individuals.

Hearing loss was also more common in males than females.

The authors noted that they may have underestimated the prevalence of hearing loss since young people often don’t recognize symptoms of hearing loss. In addition, they were unable to test children who could not remove hearing aids, who could not wear headphones and who had cochlear implants.

Due to the cross-sectional study design, they were also unable to determine a causal relationship between risk factors and hearing loss. The researchers suggested further studies to identify modifiable risk factors for hearing loss.

Source: Medical Tribune