How many times have you seen articles in the news about one medical condition being connected to another? Hearing loss is no different. Based on recent studies, here is a list of the most significant medical implications of hearing loss.
New research presented at the American Thoracic Society’s 2014 International Conference found that people with sleep apnea may have a greater risk of hearing loss.[i] Potential reasons for this link may include adverse effects of sleep apnea on vascular supply to the cochlea via inflammation and vascular remodeling or noise trauma from snoring.
A recent study published in the Journal of the Association for Research in Otolaryngology, found that smokers were 15.1% more likely to develop hearing loss, while passive smokers were 28% more likely to develop hearing loss than non-smokers.[ii] The researchers are unable to determine the exact reasons for why smoking and passive smoking increase the risk of hearing loss, but speculate that it could be due to toxins in tobacco smoke or smoking-related cardiovascular disease causing microvascular changes.
A recent study found that hearing loss is twice as common in people with diabetes as it is in those who don’t have the disease. Also, of the 86 million adults in the U.S. who have prediabetes, the rate of hearing loss is 30% higher than in those with normal blood glucose.[iii] The reasons for how diabetes is related to hearing loss are unknown. It’s possible that the high blood glucose levels associated with diabetes cause damage to the small blood vessels in the inner ear, similar to the way in which diabetes can damage the eyes and the kidneys.
Dementia & Alzheimer’s
Hearing loss may increase the risk of cognitive problems and dementia, according to a 2013 John Hopkins University Study.[iv] They also conducted a 2011 study focusing only on dementia, whereby they monitored the cognitive health of 639 people who were mentally sharp when the study began. The researchers tested the volunteers’ mental abilities regularly, following most for about 12 years, and some for as long as 18 years. The results were striking: The worse the initial hearing loss, the more likely the person was to develop dementia. Researchers say that there are plausible reasons for why hearing loss might lead to dementia — the brain’s hearing centers are very close to the regions where Alzheimer’s first starts.
Although the brain becomes smaller with age, the shrinkage seems to be fast-tracked in older adults with hearing loss, according to the results of a study by researchers from Johns Hopkins and the National Institute on Aging.[v] The report revealed that those with impaired hearing lost more than an additional cubic centimeter of brain tissue each year compared with those with normal hearing. Those with impaired hearing also had significantly more shrinkage in particular regions, including the superior, middle and inferior temporal gyri, brain structures responsible for processing sound and speech. The study also gives some urgency to treating hearing loss rather than ignoring it, saying it should be treated before these brain structural changes take place.
In a study published in The Laryngoscope, researchers found that audiogram patterns correlate strongly with cerebrovascular and peripheral arterial disease and may represent a screening test for those at risk. The authors of a study published in the American Journal of Audiology concluded that impaired cardiovascular health negatively affects both the peripheral and central auditory system.[vi]
Researchers at Brigham and Women’s Hospital (BWH) recently published study results demonstrating that a higher body mass index (BMI) and larger waist circumference are each associated with higher risk of hearing loss in women. The researchers found that when compared with women with BMI of less than 25, the risk for hearing loss was 17% higher for women with a BMI of 30 to 34, 22% higher for women with a BMI of 35 to 39, and 25% higher for women with a BMI of 40+.[vii]
Hearing-impaired adults are more likely to be depressed than those with excellent hearing – and than those who are fully deaf -according to a large U.S. survey.[viii] Higher rates of depression were most common in middle-aged women. More than 11% of people with some hearing problems scored as having moderate to severe depression, compared to 6% of people with good or excellent hearing.