Association between diabetes mellitus and hearing impairment in the adult Canadian population: data from the Canadian longitudinal study on aging

Previous studies have found an association between diabetes mellitus (DM) and hearing impairment (HI). However, standardized definitions of HI, such as those proposed by the World Health Organization (WHO), have not been commonly used in studies examining the association between DM and HI. We utilized the standardized HI definitions proposed by the WHO to assess the relationship between pre-DM, DM and HI. A cross-sectional analysis was conducted using baseline data (2012) from the Canadian Longitudinal Study on Aging (CLSA; n = 30,097). HI was defined as four-frequency pure-tone average (4FPTA) ≥ 20 decibels hearing level (dB HL) in the better ear, while disabling HI was defined as 4FPTA ≥ 35 dB HL in the better ear. We obtained the prevalence of HI and disabling HI among individuals with pre-DM, DM, and individuals without pre-DM or DM (control group). Multivariate logistic regression models were used to estimate the odds ratios (OR) for each HI outcome, adjusting for covariates and testing for interaction effects. A total of 24,048 participants were included in the analysis. Increased prevalence of HI was observed in the pre-DM and DM groups compared to the control group (44.0%, 42.9%, and 27.3%, respectively), as well as increased prevalence of disabling HI (12.8%, 11.7%, and 5.5%). After adjusting for potential confounders, individuals in the pre-DM and DM groups had up to 27% higher odds of HI (OR = 1.27, 95% CI: 1.15–1.39, p < 0.001) and up to 56% higher odds of disabling HI (OR = 1.56, 95% CI: 1.27–1.92, p < 0.001) compared to those without DM. Significant interactions were observed between DM and both age and sex for each HI outcome. Individuals with pre-DM and DM in the youngest age group, and particularly women, are at greater risk of developing HI to a degree that may hinder speech comprehension in daily life. Early hearing screening is recommended for this population.