According to researchers, patients with diabetes have a significantly higher prevalence of hearing impairment than patients without the disease.
They note that the finding is likely to be independent of the effect of ageing or a noisy environment. The number of those with impaired hearing more than doubled in the period from 1995 to 2004, researchers said.
Epidemiologically, several health problems in relation to hearing impairment have been reported such as depression and dementia.
Recently several studies have investigated the relationship between diabetes and hearing impairment but their findings were inconsistent.
"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 stria vascularis and nerves diminishing the ability to hear," said Chika Horikawa, from Niigata University in Japan and lead author of the study.
"In our study we found that persons with diabetes had more than two times higher prevalence of hearing impairment than those without diabetes," Horikawa said.
This study was a meta-analysis of thirteen previous cross-sectional studies (20,194 participants). Hearing impairment was assessed by pure-tone audiometry that included at least 2 kHz of frequency range.
The strength of the association between diabetes and prevalence of hearing impairment was not significantly influenced by whether participants were matched for age and gender or whether participants chronically exposed to noisy environments were excluded.
"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," said Horikawa.
The study was published in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
