Brain Health and Hearing
A recent commission from "The Lancet" focused on dementia. In this review, the authors outline nine potentially modifiable health and lifestyle factors from different phases of life that, if eliminated, might prevent or at least delay dementia. The authors stress that dementia, much like hearing loss, is not an inevitable consequence of aging, rather it is multifaceted and potentially 1/3 of cases preventable.
In this commission, the authors extended upon existing models of dementia risk to include hearing loss and social isolation. Next, they incorporated potentially reversible risk factors from different phases of the life span, to propose a novel life-course model of risk.
The results suggested that approximately 35% of dementia was attributable to a combination of the following nine risk factors:
- Education to a maximum of age 11-12 years (i.e., low education)
- Midlife hypertension
- Midlife obesity
- Midlife hearing loss
- Late-life depression
- Physical inactivity
- Social isolation
Prevention and management of hearing loss showed the greatest reduction in risk for dementia, approximately 9 percent of the 35 percent relative risk. However, the authors are quick to point out that the relationship between hearing loss and cognitive decline is not clear and that a common cause such as microvascular pathology may confound the association. Further, hearing loss can lead to social disengagement or increase cognitive load of a vulnerable brain leading to cognitive decline.
Also, an obvious missing factor from the list is diet, which is associated with many of the nine risk factors listed; the authors indicated that did not have data to include dietary factors, but believe it is likely an important independent risk factor.
Livingston, G et al. (2017) Dementia prevention, intervention, and care. The Lancet. July 19.