Exposure to heavy metal, even the silent kind, is a threat to hearing

David Kirkwood
December 21, 2011

BOSTON–It’s no secret that listening too long and too loud to heavy metal bands like Judas Priest, Iron Maiden, and Black Sabbath will do bad things to your ears. However, a recent paper has implicated another sort of heavy metal in hearing loss among U.S. adolescents.

Writing in Archives of Otolaryngolology--Head & Neck Surgery, Josef Shargorodsky, MD, MPH, a researcher at the Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, and his four co-authors reported on their recent inquiry as to whether exposure to heavy metals such as lead and mercury is a risk factor for hearing loss.

Drawing upon data collected in the 2005-2008 National Health and Nutrition Examination Survey (NHAMES), the scientists focused on participants in that survey aged 12 to 19. In their analysis, they looked for possible correlations between survey subjects who had audiometrically determined hearing loss with elevated levels of lead or mercury in their blood or of cadmium or arsenic in their urine. The NHAMES data included blood analyses from 2535 individuals in that age group and urinary analyses from about 875 adolescents.

They authors concluded that lead in the blood, even at levels well below the current recommended action level, was associated with substantially increased odds of high-frequency hearing loss. They also found that Individuals whose urinary cadmium levels were in the highest quartile had significantly higher odds of having low-frequency hearing loss than those in the lowest quartile.

They found no association between either mercury in the blood or arsenic in the urine and hearing loss.

The other authors were Sharon G. Curhan, MD, ScM; Elisabeth Henderson, BA; Roland Eavey, MD, SM; and Gary C. Curhan, MD, ScD.

  1. This means that recreational shooters, with typically higher blood levels of lead, are at even greater risk for hearing loss — first from the noise exposure, then from higher lead levels. (That is, unless hearing loss due to noise exposure from shooting activities was a confounding factor in this study, which seems unlikely since the study participants were in their teens.)

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