Doctors have long known that diabetes raises the risk of vision loss, but new research out of Japan has found it may also lead to hearing impairment.
The conclusion, published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism, is based on a new scientific analysis of 13 prior studies and determined diabetic patients have a markedly higher rate of hearing impairment, compared to people without the blood sugar disease, regardless of their age or exposure to a noisy environment.
"The association of hearing impairment with diabetes is controversial, but it is believed that over time, high blood glucose levels can damage vessels in the [inner ear] and nerves diminishing the ability to hear," said lead researcher Chika Horikawa, of Niigata University in Japan. "In our study we found that persons with diabetes had more than two times higher prevalence of hearing impairment than those without diabetes."
The researchers noted the number of people with impaired hearing more than doubled between 1995 and 2004. Past studies of the relationship between diabetes and hearing loss were inconclusive. But Horikawa and colleagues said their analysis of 13 studies — involving 20,194 participants — that measured hearing loss in people with diabetes conclusively indicates the two are linked.
Horikawa said the findings suggest doctors should test diabetics for hearing loss, just as they now check for vision impairment
"Our results propose that diabetic patients be screened for hearing impairment from earlier age compared with non-diabetics, from the viewpoint of prevention of several health problems such as depression and dementia caused by hearing impairment," Horikawa said.