Asymmetric hearing loss and the risk of stroke: evidence from a longitudinal cohort study.

BACKGROUND

Growing evidence suggests an association between hearing loss and cerebrovascular outcomes. However, the contribution of hearing asymmetry, which may reflect unilateral auditory vulnerability or localized cochlear and neural injury, has received limited attention. This study examined the association between asymmetric hearing loss and incident stroke in a national sample of older adults and evaluated whether this association varied by sex.

METHODS

We conducted a prospective cohort study using data from Waves 13 to 15 of the US Health and Retirement Study. The analytic sample included 11,696 adults aged fifty years or older who completed bilateral pure tone audiometry. Hearing status was categorized into normal hearing, symmetrical hearing loss, and asymmetric hearing loss. Incident stroke within two years was identified from self or proxy reported physician diagnoses. Multivariable logistic regression models were used to estimate associations, adjusting for demographic characteristics, socioeconomic factors, lifestyle variables, sensory impairments, and health conditions. Sex stratified analyses and two sensitivity analyses were performed to assess robustness.

RESULTS

Over the two-year follow up period, 182 stroke events were reported. Asymmetric hearing loss was associated with a higher risk of incident stroke compared with normal hearing in fully adjusted models (adjusted OR = 1.69, 95%CI = 1.03 ~ 2.78). Symmetrical hearing loss was not significantly associated with stroke risk after adjustment. In sex stratified models, the association between asymmetric hearing loss and stroke persisted in men, although the confidence interval was wide due to smaller subgroup sample size. No significant associations were observed among women. Sensitivity analyses that further adjusted for self-rated hearing or applied inverse probability weighting produced estimates that were consistent with the primary findings.

CONCLUSIONS

Asymmetric hearing loss was associated with incident stroke after adjustment for demographic and health related factors. These findings suggest that hearing asymmetry may reflect vascular vulnerability in older adults and may be a useful indicator in risk assessment strategies.