High lead exposure linked to hearing loss in youth

Reuters, Monday 26 Dec 2011

Teens exposed to higher-than-normal levels of lead are more likely to have trouble hearing

"It looks like the levels in the blood of most kids are very low and people are avoiding (heavy metals)," said study author Dr. Josef Shargorodsky, from the Massachusetts Eye and Ear Infirmary and Brigham and Women's Hospital in Boston.

He said studies in animals had suggested that exposure to heavy metals, which also include arsenic, cadmium and mercury, could cause hearing loss.

So his team consulted a nationally representative survey of adolescents who underwent hearing assessments and blood and urine tests for those metals.

Hearing loss was defined as not being able to hear sounds 15 decibels or softer, about the level of a whisper.

The current report comes from data on more than 2,500 participants ages 12 to 19. About one in five of them showed evidence of hearing loss.

Youth with the most lead in their blood -- at least two micrograms per deciliter -- were also the most likely to have hearing loss. Thirty-one percent of them didn't pass the hearing exams, compared to 17 per cent of those with less than one microgram of lead per deciliter.

About one in 20 of the teens tested had the highest amount of lead in their blood.

Study participants with the most cadmium in their urine also appeared to have an increased risk of hearing loss compared to those with the lowest amount. But Shargorodsky said there wasn't a clear pattern and that "it's hard to say if that's real or not."

Mercury in the blood and arsenic in the urine weren't linked to teens' risk of hearing problems. 

Sung Kyun Park, from the University of Michigan School of Public Health in Ann Arbor, said that although the amount of lead in the environment has dropped over the past few decades, the metal still shows up in the paint on some old houses, in soil and occasionally in tap water. 

Researchers said that while hearing loss is common in older adults, it can be especially hard on kids and teens because it's likely to interfere with their development and relationships with peers. 

Search Keywords:
Short link: