Readers may recall a July 2017 Lancet study which estimated 35% of the risk factors associated with dementia was modifiable, and that the most prominent modifiable risk factor was hearing loss, which contributed 9% toward the acceleration or possible onset of dementia. A study, published in JAMA Otolaryngology last week, builds on this eye-opening data. Figure 1 shows the modifiable risks factors and roughly when they are like to occur during the life span.
Using a sample size of more than 7000 adults over the age of 50, British researchers investigated the link between age-related hearing loss, cognitive decline, specifically looking at untreated hearing loss and social isolation as potential contributors of the link between cognition and hearing.
Their results showed hearing loss had a negative association with cognitive ability for participants with a moderate to severe hearing loss, but this association was only seen in those participants who did not use hearing aids. Their results suggest a key driver of the association between hearing loss and cognitive decline is untreated hearing loss.
Further, the investigators found that those with hearing loss has higher odds of being socially isolated.
Link Between Hearing Loss and Cognitive Decline
Like others similar studies that have received considerable attention in the industry press (e.g., Baltimore Longitudinal Study of Aging), this study shows hearing loss is linked to cognitive decline, with the association being greater as the degree of hearing loss increases. This current study, however, contributes one new finding: the association between hearing loss and cognitive decline was seen only in individuals who did not use hearing aids, and for the participants who wore hearing aids there was no evidence of an association between hearing loss and cognitive decline.
Another finding of interest in this study is that social isolation significantly reduces cognitive ability. Those participants with hearing loss that did not use hearing aids tended to be more prone to the ill-effects of social isolation.
According to the investigators, their findings are an indication that adults over the age of 50 ought to be routinely screened for hearing loss and cognitive decline in primary care settings. Additionally, they recommend, based on the results of this study, that more prominent public health campaigns are needed to increase the awareness that cognitive decline associated with age-related hearing loss might be preventable with opportunistic hearing screening, along with early rehabilitation.
The full text can be found at this gated site: https://jamanetwork.com/journals/jamaotolaryngology/article-abstract/2698895?resultClick=1