The No. 1 cause of mild to moderate hearing loss?

Getting older.

The National Institute on Aging calculates a quarter of Americans between 55 and 64 experience age-related hearing loss, technically called presbycusis. The percentage soars to half the population by age 75.

Hubert Lim, professor in the otolaryngology department at the University of Minnesota Medical School, and audiologist Chelsi Dodd, who supervises the Audiology and Aural Rehabilitation Center with M Health Fairview, answer questions about the physical and social consequences of not addressing hearing loss.

What do we know about causes of age-related hearing loss?

Dodd: We can diagnose hearing loss, but our testing doesn't tell us the why of the loss. It can be related to many factors; sometimes we can deduce it — prolonged noise in the workplace or with hobbies, a genetic link, medical conditions like diabetes and high blood pressure. As people come into older age, there's a higher incidence of hearing loss as factors over the life span compile.

Lim: It's clear loud sound exposure over extended periods of time leads to permanent hearing loss. The gray zone is whether the same is true with exposure to moderate sounds; do they also drive permanent hearing loss? Based on data and animal studies, I would say yes. In industrialized countries, moderate sounds include traffic, motors, appliances like blenders, lawn mowers, vacuum cleaners.

So many younger people are tied to their earbuds and noise-canceling headphones. Does that put their hearing at risk?

Lim: The trend of degraded hearing is going in this direction, with people needing help at younger ages than their parents and grandparents.

Dodd: We are starting to see earlier detectable hearing loss. As people have devices at their fingertips 24 hours a day and expose themselves to more loud sound and music, numbers will rise.

Are there advantages to getting hearing aids as soon as hearing loss is detected?

Dodd: Even if it's a mild loss, getting hearing aids will slow down the decline by keeping the hearing nerves active and stimulated by environmental sounds. If you don't use it, you lose it at a faster rate.

Lim: Hearing loss is progressive and gradual. People don't feel it happening. There's a decent amount of data that shows that the sooner you get hearing aids the better. Getting more sound in can improve your hearing health. Plus, keeping the ears activated reduces stress when you're trying to listen and you'll communicate better.

Are there lesser-known contributors to adult-onset hearing loss?

Dodd: There are ototoxic medications, which means damaging to hearing. The most prevalent are chemotherapy drugs. We make it a goal to monitor chemo patients. Their hearing may not be the top health priority when they're in treatment for cancer but sometimes if we identify notable hearing changes, oncologists can modify the dose or switch the medication.

Lim: A paper just published reported a list of symptoms related to long COVID. It found a higher incidence of both hearing loss and tinnitus (persistent ringing in the ears). We need more research to substantiate this, to find out if it's a factor or based on reports from people who were isolated and had more time to notice symptoms.

According to the National Institute on Health, only one of every three adults who could benefit from hearing aids uses them. Yet studies show older adults with hearing loss are at higher risk of developing dementia.

Lim: There's a lot of research looking at whether and how hearing loss is linked to brain degeneration as hearing nerves send fewer signals to your brain. There's also data that people with hearing loss fall more; hearing loss and balance issues are intertwined.

Dodd: We know it can be isolating when you don't hear well and it takes a huge toll on quality of life. People stop going to social gatherings because it's too hard to filter out background noise in a conversation. They pretend and laugh along and hope they are laughing at the right things. It's a loss. Communicating with others is how we learn and stay connected.

Why do people avoid hearing aids?

Dodd: There's still stigma with hearing aids. The number one thing we hear is, I don't want to look old. They think it will take a lot of time and effort to take care of something that won't help them that much.

Lim: We live in an age when people walk around with something in their ears and a lot of times no one can tell if it's a device to help them hear or something for listening. There are people who won't wear hearing aids fitted in the ear and nearly invisible but will walk around with wireless headsets or earbuds, which are way more conspicuous.

Everything about hearing aids has gotten smaller except the price. The cost can be prohibitive. Is there help on the horizon?

Lim: The Food and Drug Administration announced a new category, "personal sound amplification devices," coming in the future for those with milder hearing loss; some are already available. They can't be called hearing aids because they don't require a prescription. These consumer products will be sold over-the-counter and will be more accessible to people who can't afford traditional hearing aids.

Are there other options to make hearing health more affordable?

Dodd: Every week we help people who got used hearing aids from someone who passed away, got new ones or donated them or that they bought secondhand. They're deep cleaned and customized for a new owner. It's wonderful, but the caveat would be the new owner needs to see a hearing professional to make sure the device is properly programmed for them. Not all hearing aids can be reused; some are custom fit.

What's involved in baseline hearing tests?

Dodd: We start by looking in the ears. It's shocking how many people don't hear well because their ears are plugged with wax.

We recommend testing every two years for adults. Get a baseline during your physical so we have something to compare it to if there are changes.

In one portion of the hearing test, the subject listens for beeps at different frequencies. We're looking for the threshold for the softest sound they detect. The other portion looks at clarity. We have a list of words they repeat back; we have word lists in languages besides English.

How can people of any age be proactive to preserve hearing?

Lim: Even though using ear protection is more mainstream, I'm surprised there's not more awareness of hearing health. People want to know what's in their food or what pesticides they're exposed to. I predict they'll want to know what sound could be dangerous and avoid it. It's like how knowledge that secondhand smoke is harmful changed behavior. Some pretty accurate phone apps already track how loud a room is, in public at a concert or restaurant or at home. They can tell you if the sound is too much.

When it comes to ear protection, do you practice what you preach?

Lim: Yeah, most of the time. I have three kids under the age of 8 and they have ear protectors that we use pretty diligently. I'm not in a place to clinically recommend things, but we've made it a habit in noisy environments.