A new study has found an association between iron deficiency anemia and the development of a specific type of hearing loss, adding to the problems caused by lack of iron in the human body, according to livescience.com.

Researchers evaluated the results from over 300,000 adults in Hershey, Pennsylvania, ranging in age from 21 to 90, with an average age of 50, and found adults with iron deficiency anemia were more than two times likely to develop combined hearing loss as those who were not anemic.

Hearing loss was grouped into three categories for the study’s purposes.  The first, called sensorineural hearing loss, was defined as resulting from damage to the inner ear or the nerves that connect the ear to the brain.  The second, conductive hearing loss, happens when sound is unable to travel through the ear.  Combined hearing loss is a combination of the first two.

The results show that those with iron deficiency anemia were 2.4 times as likely to develop combined hearing loss as those without the deficiency, and 1.8 times more likely to have sensorineural hearing loss.  Coincidentally, the study failed to find a link between iron deficiency anemia and conductive hearing loss.

Previous research had suggested some reasons why hearing loss may be associated with iron deficiency anemia, according to Kathleen Schieffer, a doctoral student at Pennsylvania State University College of Medicine and one of the authors on the study.

The lack of iron has been linked with several disorders of the blood the can damage the tiny blood vessels in the ear that could lead to hearing loss.  Low iron has also been linked to a condition that affects myelin, a covering of nerve cells, including the nerve that connects the ear to the brain.

A previous study from Taiwan found a link between iron deficiency and a type of hearing loss that occurs in fewer than 72 hours, called sudden sensorineural hearing loss, according to the researchers.

The researchers cautioned the study did not prove iron deficiency anemia caused hearing loss, and called for more research to further investigate the relationship, including whether iron supplements could help prevent this type of hearing loss.

The findings were published in the journal JAMA Otolaryngology-Head and Neck Surgery.