Many seemingly unrelated aspects of aging correlate with one another in incidence and progression. All of the myriad manifestations of degeneration aging arise from the same small set of underlying processes of cell and tissue damage, so such correlations are perhaps unsurprising. There are cases in which a direct causal connection is found, as in the case of hearing loss contributing to dementia, but in the case of hearing loss and frailty we might expect correlation to arise from shared underlying mechanisms, such as the chronic inflammation that is characteristic of later life.
In a nationally representative sample of older adults in the U.S., worse hearing continuously was associated with greater odds of being frail and pre-frail versus robust after adjusting for sociodemographic and health characteristics. Across hearing categories, those with moderate or greater hearing loss had 84% and 46% greater odds of being frail and pre-frail versus robust, respectively, compared to those with no hearing loss. In age-stratified analyses, the association of worse hearing with being frail versus robust remained significant among older adults aged 71-80 only. Furthermore, lack of hearing aid use was associated with greater odds of being frail and pre-frail versus robust, and frail versus pre-frail.
How hearing loss may be linked to frailty in older adults is not clear. Hearing loss impairs encoding of sound resulting in difficulty with communication and hinders spatial awareness. This may eventually lead to cognitive and physical decline via constantly high cognitive load due to effortful listening, greater risk for social isolation, and depression, and a poorer physical function profile including slower gait speed, lower levels of physical activity, and more falls. Furthermore, these manifestations may negatively impact and reinforce one another in a vicious cycle. For example, hearing loss may cause social withdrawal which in turn may contribute to physical decline and more social withdrawal. Therefore, the underlying mechanisms potentially linking hearing loss to frailty may be related to cognitive and physical decline. Interestingly, we found that the studied associations were stronger among participants ages 71-80 years, suggesting that hearing loss at a relatively younger age may have a greater impact on frailty risk.