Diabetes Linked to Ear Damage

NEW YORK (Reuters Health) - Type 1 diabetes can damage the vasculature and inner structure of the ear, according to a new report.

Previous research suggests that diabetes can cause hearing loss, the authors explain in the journal Otolaryngology-Head and Neck Surgery, but no previous study has measured and documented changes in the anatomy of the cochlea -- the deep-seated spiral structure where sound is turned into nerve impulses -- in patients with type 1 diabetes.

Dr. Hisaki Fukushima from the International Hearing Foundation in Minneapolis, Minnesota, and colleagues examined skull bones obtained at autopsy from patients with juvenile onset diabetes and compared them with similar bones obtained from normal "controls."

Diabetics had significant thickening of the walls of blood vessels supplying the cochlear region, the team reports, as well as a significantly greater loss of outer "hair cells," which pick up sound waves. Other structures were more shrunken.

"The findings in our study suggest that the (microvessel damage) associated with diabetes affects the inner ear vasculature and causes degeneration of inner ear structures," Fukushima and colleagues write.

Type 1 diabetes "results in changes of the cochlea...that are likely to result in hearing loss," they conclude.

SOURCE: Otolaryngology-Head and Neck Surgery, July 2005.