Hearing Aid Use Correlates with Reduced Mortality Risk
The manifestations of aging, such as age-related diseases and mortality, all arise from the same underlying root cause mechanisms of damage and dysfunction. If an individual exhibits evident consequences of aging in one part of the body, in the form of a specific age-related condition, it is likely that the burden of damage and dysfunction throughout the body is high enough to cause other specific age-related conditions to arise as well. It doesn't necessarily mean that the conditions are linked in any way other than being consequences of the same processes. That said, aging is complex, everything in the body and brain is connected to at least some degree, and dysfunction in one system often does add to the dysfunction of other systems in ways that are distinct from the core mechanisms of aging. One might not think that to be the case for hearing loss, except for the fact that use of hearing aids reduces risk of mortality via cardiovascular disease, as demonstrated here. Possible explanations are that (a) hearing aid users tend to take better care of their health and function in other ways as well, or (b) there is some functional path linking the accelerated neurodegeneration that is known to take place without functional hearing and cardiovascular mortality.
Hearing loss affects more than 1.5 billion people or nearly 20% of the global population. Prevalence is increased particularly among the ageing population, and is linked to various adverse outcomes, including poorer health, diminished quality of life, depression, and cognitive decline. Emerging evidence suggests that hearing loss could also be linked to higher mortality risk. Most existing studies have relied on smaller sample sizes based on cohorts of older adults (aged between 50 years and 80 years or more), overlooking younger (aged 20-49 years) populations. Most studies have been observational and have not assessed the long-term effect of hearing-aid use among those with hearing loss.
Results of previous studies of association between hearing-aid use and mortality have been mixed. To address these limitations, our study conducted an individual participant data (IPD) meta-analysis using large datasets from Australia, Iceland, and the USA, followed by a replication study using data from Norway, to examine the relationship between hearing-loss severity, hearing-aid use, and mortality. These studies provided extensive audiometric and mortality data, enabling a robust examination of the relationship between hearing loss and mortality across different populations and settings while adjusting for key confounding variables.
The IPD meta-analysis included 13,851 participants, with a mean age of 61.8. Mild (1.19), moderate (1.55), and moderately severe or worse (1.56) hearing loss were associated with increasing all-cause mortality risk. Mild (1.18), moderate (1.43), and moderately severe or worse (1.30) hearing loss were also associated with increased cardiovascular-related mortality risk. Current use of hearing aids was associated with reduced all-cause mortality risk [0.91] and reduced cardiovascular-related mortality [0.85]. The replication study of 50,277 adults corroborated these findings.