title: Diabetes and risk of hearing impairment in adults: a meta-analysis.
abstract: BACKGROUND
  Recently, several studies have investigated the relationship between diabetes and hearing impairment, but results were inconsistent.
  
  
  OBJECTIVE
  Our objective was to compare the prevalence of hearing impairment between diabetic and nondiabetic adults.
  
  
  METHODS
  We performed a systematic literature search using MEDLINE (1950 to May 30, 2011) and EMBASE (1974 to May 30, 2011).
  
  
  METHODS
  Cross-sectional studies were included if data on numbers of hearing-impaired and non-hearing-impaired cases with diabetes were presented. Hearing impairment was limited to that assessed by pure-tone audiometry that included at least 2 kHz of frequency range and was defined as progressive, chronic, sensorineural, or without specified cause.
  
  
  METHODS
  Two authors independently extracted relevant data. Odd ratios (ORs) of hearing impairment related to diabetes calculated in each study were pooled with the random-effects model.
  
  
  RESULTS
  Data were obtained from 13 eligible studies (20,194 participants and 7,377 cases). Overall pooled OR (95% confidence interval) of hearing impairment for diabetic participants compared with nondiabetic participants was 2.15 (1.72-2.68). OR was higher in younger participants (mean age, ≤60 yr) than in those over 60 yr among which the OR remained significant (2.61 and 1.58, P = 0.008). 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 (P = 0.68) or whether participants chronically exposed to noisy environments were excluded (P = 0.19).
  
  
  CONCLUSIONS
  Current meta-analysis suggests that the higher prevalence of hearing impairment in diabetic patients compared with nondiabetic patients was consistent regardless of age.
authors.affiliation: Department of Hematology, Endocrinology, and Metabolism, Niigata University Faculty of Medicine, 1-757 Asahimachi-dori, Chuoh-ku, Niigata, Japan 951-8510.
authors.forename: Chika
authors.initials: C
authors.lastname: Horikawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Kodama
authors.forename: Shiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Kazuya
authors.initials: K
authors.lastname: Fujihara
authors.forename: Reiko
authors.initials: R
authors.lastname: Hirasawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yachi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shimano
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yamada
authors.forename: Kazumi
authors.initials: K
authors.lastname: Saito
authors.forename: Hirohito
authors.initials: H
authors.lastname: Sone
mesh_terms: D000328:Adult; D017668:Age of Onset; D000465:Algorithms; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000453:epidemiology*; D003920:Diabetes Mellitus / Q000453:epidemiology*; D034381:Hearing Loss / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015995:Prevalence; D012307:Risk Factors