25 February 2011
Older adults with hearing loss may be up to 5 times more likely to develop dementia than people with normal hearing, researchers have found (Arch Neurol 2011; 68: 214-20).
In a prospective study of 639 people aged 36–90 years, researchers found an independent association between hearing loss and development of dementia over 12 years. The risk became evident with hearing loss greater than 25 decibels and increased as hearing impairment worsened, after taking into account age, race, diabetes, smoking, hypertension (high blood pressure) and other dementia risk factors, they said.
Compared with people with no hearing loss, people with mild hearing loss had 1.9 times the risk of developing dementia; those with moderate hearing loss had 3 times the risk and those with severe hearing loss had 4.9 times the risk.
Among people older than 60 years, hearing loss could account for almost one-third of the observed risk of dementia, the researchers estimated.
"Whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study", they said.
Other studies have found similar associations, leading to speculation that hearing loss may contribute to progressive loss of brain function by reducing stimulation and hampering social interaction, the researchers said.
Another possibility is hearing loss and dementia are caused by a common neuropathological process, they said.
Last Reviewed: 28 February 2011