Researchers Find Iron Deficiency Associated with Hearing Loss

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About 20% of Americans, or 48 million people, report some degree of difficulty hearing. Although many cases of hearing loss have no known cause, scientists, doctors, and researchers around the world are learning more every day about how hearing works and the factors that may contribute to--or help prevent--this extremely common condition. The latest discovery? Iron-deficiency anemia may be linked to hearing loss.

As iron deficiency anemia (IDA) is prevalent and fairly easily treated, further understanding of the link between IDA and hearing loss may create new possibilities for early identification and appropriate treatment for those with hearing problems.


What is iron-deficiency anemia?

A condition in which the blood lacks enough healthy red blood cells, anemia is a common and treatable health issue. Red blood cells are responsible for carrying oxygen to the body's tissues. Iron-deficiency anemia is anemia that is caused by insufficient iron, the lack of which hinders the ability of your red blood cells to carry oxygen (hemoglobin). IDA may cause fatigue and shortness-of-breath, but it is easily diagnosed with a blood test, and correctable with iron supplementation.


IDA and hearing loss: how the study was carried out

A research team at the Pennsylvania State University College of Medicine, led by Kathleen M. Schieffer, B.S., examined data from 305,339 men and women between the ages of 21 and 90 years who visited Penn State Hershey Medical Center during 2011-2015 and had information available concerning serum ferritin and hemoglobin levels (low levels of these substances indicate IDA). Of the people in the study, 4,807 had hearing loss and 2,274 had iron deficiency anemia. The researchers sought to determine whether there was an association between the two.

By the end of the study, Schieffer and her team had established a tangible link between hearing loss and IDA; they published their findings in the online journal JAMA Otolaryngology-Head & Neck Surgery on December 29, 2016.  

Key findings:

  • The risk for hearing loss was nearly two and a half times as high in those with anemia.
  • The risk for sensorineural hearing loss, the type associated with nerve pathways from the inner ear to the brain, was 82 percent higher in those deficient in iron.
  • There was also an increase in risk for conductive hearing loss, caused by a problem in the ear canal, eardrum or bones of the middle ear--though this risk was insignificant.
  • The odds of having combined hearing loss (conductive and/or sensorineural loss, deafness or loss due to unknown causes) were increased by more than two times in adults with IDA.


How does iron-deficiency anemia contribute to hearing loss?

The exact reason for the link between the two remains unknown, but animal studies have provided some clues. In these studies, it was found that low levels of iron may reduce blood flow to the inner ear, affecting the cochlea ganglion--a collection of nerve cells that transmit sound to the brain. The authors of the study note that blood is supplied to the cochlea of the ear by only one artery, and that low hemoglobin levels may result in “ischemia” or an inadequate blood supply to this area.


What does this mean for people with anemia?

For the time being, the authors of the study say that it is too soon to tell definitively if anemia causes hearing loss. More research is needed, and they aren’t yet recommending that those with hearing loss get blood tests for anemia. The findings only show a possible connection between the two.

Still, Schieffer and the other researchers want to undertake more research to understand if treating the blood condition might help to improve or prevent hearing loss, especially since IDA is so common and treatable. "An association exists between IDA in adults and hearing loss. The next steps are to better understand this correlation and whether promptly diagnosing and treating IDA may positively affect the overall health status of adults with hearing loss," the authors said.

The results look the most promising for those with sensorineural hearing loss -- usually considered a permanent condition. If iron deficiency anemia is strongly associated with sensorineural loss, there is hope that further investigating the link between the two might lead to improvements in hearing in the not-too-distant future.  


Are you concerned about your hearing? Have you noticed a change in your hearing abilities? The first step toward better hearing health is scheduling a hearing test. Contact us at Sound Hearing Group today.