Association of Hearing Loss With Dementia.

IMPORTANCE

Hearing loss (HL) may be a modifiable risk factor for dementia, and longitudinal studies are needed to examine the association of HL and dementia.

OBJECTIVE

To investigate the association of HL with incident dementia in Taiwanese adults in the general population.

DESIGN, SETTING, AND PARTICIPANTS: This population-based cohort study collected data from the National Health Insurance Research Database of Taiwan. Patients newly diagnosed with HL from January 1, 2000, through December 31, 2011 (n = 8135), constituted the exposed (HL) group. The HL group patients were matched by sex, age, residence, and insurance premium to individuals without HL (non-HL group) (n = 8135). Data were analyzed from January 1, 2000, to December 31, 2013.

EXPOSURE

Hearing loss defined according to International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes.

MAIN OUTCOMES AND MEASURES

Dementia classified according to ICD-9-CM codes.

RESULTS

Of a total of 16 270 participants (9286 [57.1%] men; mean [SD] age, 65.2 [11.1] years), 1868 developed dementia. The dementia incidence rate in the HL group was higher than that in the non-HL group (19.38 [95% CI, 18.25-20.57] per 1000 person-years vs 13.98 [95% CI, 13.01-15.00] per 1000 person-years) during the follow-up period. In the fully adjusted multivariate Cox proportional hazards regression model applied for risk analysis, patients with HL had a significant risk of dementia (hazard ratio [HR], 1.17; 95% CI, 1.07-1.29; false discovery rate [FDR] P = .003). Subgroup analysis revealed that, among 3 age groups (45-64, 65-74, and ≥75 years), the group aged 45 to 64 years was associated with a risk of dementia (HR, 2.21 [95% CI, 1.57-3.12]; FDR P < .001). In sensitivity analysis, the presence of HL among those aged 45 to 64 years (HR, 1.40; 95% CI, 1.12-1.75; FDR P = .01) was associated with a risk of dementia.

CONCLUSIONS AND RELEVANCE

In this study, hearing loss was positively associated with a risk of dementia, especially in patients aged 45 to 64 years. Hearing protection, screening, and treatment may be used as strategies for mitigating this potential risk factor.