In only the last dozen years, many important studies have surfaced linking hearing loss to disabling conditions such as cognitive decline and Alzheimer’s disease, clinical depression, diabetes, falls among the elderly, heart disease and many more. These linkages are often referred to as “comorbidities,” which is defined as the simultaneous presence of two or more chronic conditions or diseases in a person. A “chronic condition” is defined as a health condition or disease that is persistent or otherwise long-lasting in its effects. The term chronic is applied when the course of the disease lasts for more than three months. Using this definition, hearing loss clearly qualifies as a chronic condition.
Seven Comorbidities Linked to Hearing Loss
- Social isolation and loneliness. Although social isolation and loneliness are usually looked at as different constructs, for the purpose of this general discussion the two are combined here. The researchers measured loneliness using the UCLA Loneliness Scale, and found that younger-age hearing loss was significantly correlated with greater loneliness. Other depressive symptoms and hearing-related quality of life, communication difficulties, emotional well-being, mental health on the 36-item Medical Outcomes Study Short-Form (SF-36) were also negatively correlated with loneliness.
- Depression. Recent research shows that there appears to be a direct relationship with the prevalence of moderate-to-severe depression being 4.9 percent for people reporting excellent hearing, 7.1 percent for those with good hearing, and 11.4 percent for those reporting a little trouble or greater hearing loss. This study also contains some interesting data that shows how, as the hearing loss increases, the incidence of depression also increases. The trend appears to be more obvious for women, and the exceptions to this were people who reported themselves to be “deaf.”
- Falls. Falls are the leading cause of fatal and non-fatal injuries among the elderly leading to significant health, social, economic and emotional consequences. Falls often lead to fatal outcomes within the first 12 months of a fall with injury in the senior population. Research has shown an increase in falls by 1.4 percent increasing to a much larger percentage the more hearing loss a person has.
- Cardiovascular disease. An interesting 2009 study by Friedland and colleagues published in Laryngoscope showed that the audiometric patterns – particularly low-frequency (sloping) and flat (strial) losses – were strongly correlated with cardiovascular disease. In fact, the researchers reported that patients with low-frequency hearing loss should be regarded as “at risk” for cardiovascular events, and appropriate medical referrals should be considered. One chart in the study suggests that about 85 percent of diagnosed strokes were associated with individuals who had flat or low-frequency sloping losses, causing the authors to suggest that the vascular pathology extended throughout the body, including the ears.
- Diabetes. A study looking at the association between hearing loss and diabetes was conducted by Kathleen Bainbridge and colleagues, published in the July 2008 edition of the Annals of Internal Medicine. They found that people with diabetes had significantly increased odds of hearing impairment in worse and better ears at all severity levels and frequencies. It appears that prevalence of hearing loss among those people with diabetes was more than twice that than those without diabetes. The association between hearing loss and diabetes was actually stronger among those people younger than age 60, and was independent of gender or chronic exposure to noise.
- Cognitive impairment and dementia. Perhaps the landmark study that elevated the interest of healthcare professionals and the public about this topic was the paper by Dr. Frank Lin and colleagues published in 2011. The results showed that, compared with normal hearing, the hazard ratio for incident all-cause dementia was 1.89 for mild hearing loss, 3.0 for moderate hearing loss, and 4.94 for severe hearing loss.
- Mortality. As if all these comorbidities are not enough, it turns out that there may even be a relationship between hearing loss and mortality. The Reykjavik study by Fisher, et al, examined the vision and hearing of 4,926 Icelandic individuals ages 67 years or older between 2002-2006 who were prospectively followed for mortality through 2009. In the study, individuals with hearing loss had a higher risk of death from all-cause cardiovascular disease than those without hearing loss. QCBN
By Karon Lynn, Au.D.