Collaboration with Apple and World Health Organization studies sound exposure impacts on hearing
University of Michigan researchers target invisible health threat affecting millions
By Matt Markey
Public health advisories typically emphasize diet, exercise, preventive medicine, and environmental safety—encouraging us to eat well, stay active, get checkups, and avoid hazards like tobacco and pollution. Visual reminders of these priorities surround us daily, from grocery store produce displays to "No Smoking" signs. However, one critical health concern remains largely overlooked: protecting our hearing from the constant noise we face throughout each day.
A groundbreaking endeavor in hearing health research is being conducted by the University of Michigan School of Public Health in partnership with Apple and the World Health Organization (WHO) is focused on advancing our understanding of how hearing could be impacted over time by exposure to sound at certain levels.
According to Rick Neitzel, professor of Environmental Health Sciences and Global Public Health at Michigan Public Health and the lead researcher on the Apple Hearing Study, this unique collaboration is helping to expand our understanding of how the sounds around us impact our hearing health, overall health, and quality of life.
"For various reasons, as a country we have really leaned into protecting ourselves from sun exposure, air pollution, and contaminated water—because the impacts of those exposures are noticeable," said Neitzel, also the director of the University of Michigan's Center for Occupational Health and Safety Engineering.
"Often if someone gets injured in the workplace, the damage is immediately evident. With hearing loss, though, you don't get sunburned or cough or bleed, and the damage doesn't always cause pain, so hearing loss is often not considered a priority.”
Neitzel added that prior to this ongoing study, there was very little data available on the impact listening behaviors might have on an individual's hearing and overall health.
He believes that combining the research capabilities of the University of Michigan and the reach of Apple users across the United States has enabled the team to gather sound exposure data from an extensive group of study participants and advance the understanding of how sound exposure over time can impact our hearing and our health in a way that otherwise would simply not have been possible.
The Apple Hearing Study, which began in 2019 and involves more than 160,000 consenting participants, seeks to understand typical headphone listening patterns and sound exposures, and their link to current and future hearing health. The research also looks at how study participants interact with data about those listening patterns and environmental sound exposures.
The study utilizes the innovative technology of iPhone and Apple Watch through the Research app to evaluate data including environmental sound levels and headphone audio levels. The study participants also have their hearing ability—as well as any tinnitus (ringing or noise in the ears) that they experience—monitored using a variety of surveys and tests.
“One objective goal of this study is really—for the first time—to learn how much sound exposure people get through their earbuds and headphones," Neitzel said, "as well as how much noise they get from their general environment, and to look at the relationship between those exposures and hearing.”
Apple Watch users taking part in the study can also consent to share data such that the research team can look at the relationship between environmental sound exposure and cardiovascular health. The team intends to develop a better understanding of typical environmental sound exposures and the relationship of these to current and future cardiovascular health.
Neitzel said that previous studies have suggested there also is a connection between noise exposure and some of the more common health problems we see in society. He said exposure to unsafe levels of noise has been associated with cardiovascular disease, depression, high blood pressure and stroke.
"These serious health issues are increasingly being linked to noise exposure," he said, "so enhancing our understanding of this connection is very important.”
"Studies done in Europe have connected noise to some of the top threats to our health, but in the US we have yet to recognize, much less to act on, this link," Neitzel said, adding that learning more about the possible connection between hearing loss and cardiovascular complications will have major benefits. "For too long there has been this acceptance of noise as an unavoidable consequence of living in modern society.”
Previous research has shown that hearing loss also can lead to a significant reduction in the quality of life, including but not limited to isolation, diminished communication with loved ones, loss of employment, relationship problems, depression, and reduced cognitive function. In older adults, studies show that hearing loss is associated with the increased occurrence of falls, dementia and other adverse health outcomes.
"We have this tendency to view hearing loss as a normal part of aging, thinking 'I am going to lose my hearing as I get older,'" Neitzel said. "We just haven't recognized how debilitating hearing loss can be, and that hearing loss from noise is completely preventable. Once you have a hearing loss, it has the potential to cut you off from people and can lead to many other serious issues.”
The research team's work has been aided by the advanced technology of Apple devices including iPhone and Apple Watch, since by using these devices, researchers are able to gather critical data in a less intrusive manner than what was available in the past. Neitzel said that in prior studies he has collected many thousands of hours of noise exposure data using special devices that study participants had to wear.
"Using the Research app on iPhone to share data is a game-changer, as is the ability to measure sound levels using Apple Watch," he said. "People use these devices every day, and now for the first time, we can use them to get a comprehensive view of people's sound exposures. This is really a quantum leap.”
Looking more broadly at the problem, Neitzel said that hundreds of millions of people across the globe likely suffer from noise-induced hearing loss. While hearing loss has historically been linked to certain working environments where exposure to occupational noise is very high, recreational exposures appear to be on the rise in the US and around the world and may be increasingly responsible for hearing damage in society.
The sources of these recreational sounds include attendance at sporting events and concerts, using public transportation, listening to music and other media, riding motorcycles, using noisy power tools, and more. Data from other studies indicates that about 90% of US residents living in urban settings are exposed to noise levels above the level considered safe by the WHO.
Data from this study is shared with the WHO through its "Make Listening Safe" initiative. The WHO estimates that by 2050, there will be more than 700 million people worldwide suffering from significant hearing loss.
Neitzel added that the national scale of the Apple Hearing Study provides the research team at the University of Michigan and Apple with the opportunity to share the study's groundbreaking findings in an effort to improve and promote hearing health.
"The information gained from this study," he said, "can improve our understanding of potentially harmful exposures and help identify ways that people can proactively protect their hearing and overall health."
Media Contact
Destiny Cook
PR and Communications ManagerUniversity of Michigan School of Public Health734-647-8650