Earlier this year, a group of international experts
on dementia commissioned by The Lancet, a British medical journal, to study
“dementia prevention, intervention and care,” reported their findings.
Part of the report took a fresh look at risk
factors for dementia and found that more than a third of our risk is likely
modifiable. That is, we can do something about it, as opposed to risk
controlled by genetics. Most of the modifiable risk factors have been discussed
in previous columns (increasing formal education, controlling high blood
pressure and diabetes, exercising regularly, avoiding obesity and smoking,
treating depression adequately and being socially engaged). But the single
strongest potentially modifiable risk factor in their research was a surprise
to me and many others — hearing loss.
According to their calculations, 35 percent of
dementia can be blamed on the nine risk factors listed above. Among those
factors, more than one-fourth is linked to hearing loss.
Why does hearing loss make dementia more likely?
The mechanism for creating problems with thinking due to decreased hearing is
“not yet clear," according to the authors of the report, but is probably
related to adding to the “cognitive load” of a vulnerable brain. If you don’t
hear well, it makes the brain work harder to try to interpret what is going on
around it, increasing levels of background stress in many minute-by-minute
interactions. In addition, not hearing well may lead to increased risk of
social disengagement and even depression.
Certain subgroups seem more likely to develop poor
hearing. Men are twice as likely as women to have hearing impairment. Years in
school also seem to matter, less education is associated with hearing loss.
However, noise on the job (previously associated with lower education levels in
workers) didn’t seem to matter, even though very loud noise can damage hearing.
People are exposed to less noise at work than they
were 30-50 years ago due to changes in regulations regarding noise on the job
and an increase in white collar positions. Obesity also increases the risk for
hearing loss, as does smoking and poorly controlled diabetes (but the high
level of risk for dementia due to hearing loss is present even without these
“co-factors”).
What can we do to protect our hearing? First, avoid
very loud noises. Prolonged exposure to any noise over 85 decibels (dB), such
as heavy city traffic, a busy school cafeteria or a lawn mower, can cause
gradual hearing loss.
No more than 15 minutes of unprotected exposure to
noise above 100dB (wood shop, snowmobile, maximum volume level of a personal
listening device) is recommended.
Remember that few types of headphones shut out all
or even most ambient noise, so listening to music on your iPhone or other
device while mowing the lawn creates additive noise levels. Regular exposure to
more than a minute of 110dB noise risks permanent hearing loss (rock concerts,
ambulance sirens, jet take-offs, fireworks at close range , shotgun blasts,
etc.)
If your ears ring after a noise exposure, this
suggests that a least a tiny bit of permanent damage has been done to your
hearing.
What about dietary supplements? We have said before
that a wide variety of fruits and vegetables (filling half our plates when we
eat) is better than a load of supplements. Research suggests that folate,
beta-carotene and other carotenoids, and omega-3 fats are some of the likely
protective components, but there are likely many more in that half plate of
fruits and vegetables. The healthy fats in a couple of servings of fish per
week are also likely to help us hear better.
What about hearing aides? We don’t have research to
support their use to decrease risk of dementia yet.
But we do know that effective aides can improve
social interactions and make interpersonal relationships less stressful. If you
are over 50 and haven’t had your hearing tested, it is probably a good idea (at
your primary doctor’s office; ear, nose and throat specialist, or independent
audiologist). If you prefer, another low cost screening called the National
Hearing Test requires only a land line telephone and a quiet room in your home.
SOURCE: The Post and Courier, Lauren Sausser
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