Hearing tests conducted in February at the American Diabetes Association's Expo in Portland, OR, showed that more than half of the 400 people tested had hearing loss. Approximately 4,000 people came to the expo, and hearing tests were available through Sonus, the hearing aid manufacturer, that's now partnering with the ADA to perform screenings at such events. “We knew there was a link, but there were so many [people with diabetes] who showed hearing loss,” said Danielle Yoder, coordinator of the ADA event.
Run by a local branch of the ADA, the free event is held annually in Portland's downtown convention center. Screenings at the expo have been going on for the past several years, thanks to the Oregon Lions Sight & Hearing Foundation. This means, however, that they've been relatively limited in scope. This year, with two locations, the capacity for testing has more than doubled, and the combined numbers were startling.
It's no surprise. Diabetes and hearing loss are two of the most common health problems in the United States, and diabetes is the seventh leading cause of death. Approximately 26 million people have diabetes, and an estimated 34.5 million have hearing loss, according to the ADA. (See FastLinks.) Diabetes is characterized by high blood glucose levels, resulting from the body's inability to produce or use insulin. Twenty-seven percent of those 65 and older have diabetes, and 43 percent have hearing loss. (See FastLinks.)
This coincides with the results from the expo. More than 50 percent of those screened had a 30 dB hearing loss, said Bob Tysoe, Sonus' Portland-based marketing manager. “Observationally, the majority of those tested were senior citizens, and proportionally, more women than men were tested,” he noted.
Nearly 100 percent were unaware that hearing loss was associated with diabetes, had never received a physician's recommendation for a hearing test, and were enthusiastic about knowing their results, Mr. Tysoe added.
NEW STUDY PROVIDES ANSWERS
A group of researchers at Henry Ford Hospital in Detroit recently released study results that seem to underscore a possible, if only partial, solution. Approximately 1,000 patient charts were reviewed, and the results showed substantial differences in hearing in those with diabetes when compared with their counterparts, according to pure-tone audiometry studies.
The data, however, also indicated that women with diabetes were likely to experience serious hearing loss over time, although men had worse hearing across the age spectrum. Some women showed signs of significantly worsening hearing well before age 60 compared with others who didn't have the disease. The impact looked even more dramatic in women with diabetes when blood glucose levels were not being well-controlled by medication and diet. Poor diabetes control may accelerate the loss, the investigators suggested.
Lead author of the retrospective study, Derek J. Handzo, DO, said the same processes responsible for changes to other organ systems in diabetes also undermine structures in the ear. Hearing loss in those with diabetes seems related to blood flow impairment in late-stage diabetes, said Kathleen Yaremchuk, MD, who led the effort and is the chair of otolaryngology, head and neck surgery at the Henry Ford Health System. “Just as smoking cigarettes leads to lost lung function,” the encroaching impact of diabetes on hearing may be imperceptible until it's irreversible, she added.
The researchers plan to conduct a prospective study to determine if differences in hearing acuity can be more directly tied to lifestyle factors, such as effective disease management and healthy personal habits, Dr. Yaremchuk said.
Those who assisted with the screenings at the Portland expo said they were surprised by the study results. “[Years ago,] we really didn't know how much of an impact diabetes had on the auditory system,” said Peter Charuhas, an audiologist for Sonus in Portland. “Yes, there were a few articles that offered a possible relationship,” he said, but “once the data started coming out from larger, well-designed studies, it began to grab our attention and [encourage] discussion.
“When it started coming out that there was a relationship between diabetes and hearing loss, I started looking for it in my patients,” Mr. Charuhas noted. “It turned out many were type 2 diabetics,” he said.
Researchers have also found that prediabetic adults with blood glucose levels higher than normal but not high enough to be diagnosed with diabetes have a much higher rate of hearing loss compared with those who have normal blood sugar levels. (Ann Intern Med 2008;148:855.) Data from a federal health survey nearly four years ago discovered a higher rate of hearing loss in those with diabetes after analyzing the audiology tests of a cross-section of several hundred U.S. adults. (Ann Intern Med 2008;148:855.) (See FastLinks.) The association between diabetes and hearing loss was found at all frequencies, but the strongest link was in the high frequency range. The screenings conducted at the expo were at 25 dB for 500, 1,000, 2,000, and 4,000 Hz.
This information offers a potential powerful route to change, said Mr. Tysoe, who said he was struck by how “treatable” these men and women seemed. They had failed in the high-frequency ranges and “what is lost is lost,” he said, but those tested were seeking answers. “I think that's the key,” Mr. Tysoe said. “This is something that we can do something about,” he said. The answer lies not only in technology to help people with diabetes hear better but in prevention, he stressed.
Lifestyle Factors that Affect Hearing Loss in People with Prediabetes or Diabetes
* A diet high in antioxidants may help preserve vascular health, in turn protecting against hearing loss. (Fundam Clin Pharmacol 2007;21:111.)
* Increasing serum creatinine levels may indicate a pending hearing loss. (Otol Neurotol 2003;24:382.)
* Risk factors for heart disease, including family history, may mean a higher risk for sudden sensorineural hearing loss. (Audiol Neurotol 2010;15:111.)
* Increased vulnerability to ototoxic medications may occur, necessitating close monitoring of drug therapy. (Audiol Neurootol 2006;11:1.)
* Read more about diabetes and hearing loss at http://bit.ly/ADAFacts.
* More information about senior citizens and hearing loss is at http://bit.ly/SeniorFacts.
* Results from a federal health data survey are at http://1.usa.gov/NIHstudy.
* Click and Connect! Access the links in The Hearing Journal by reading this issue on thehearingjournal.com.
* Comments about this article? Write to HJ at HJ@wolterskluwer.com.
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