Alzheimer’s prevention may be less about new drugs, more about income, zip code and education
That your risk of Alzheimer’s disease depends on your salary, what you ate as a child, or the block where you live may seem implausible. But researchers are discovering that social determinants of health (SDOH) play an outsized role in Alzheimer’s disease and related dementias, possibly more than age, and new strategies are emerging for how to address these factors.
At the 2022 Alzheimer’s Association International Conference, a series of presentations offered evidence that a string of socioeconomic factors—such as employment status, social support networks, education and home ownership—significantly affected dementia risk, even when adjusting data for genetic risk. What’s more, memory declined more rapidly in people who earned lower wages and slower in people who had parents of higher socioeconomic status.
In 2020, a first-of-its kind study in JAMA linked Alzheimer’s incidence to “neighborhood disadvantage,” which is based on SDOH indicators. Through autopsies, researchers analyzed brain tissue markers related to Alzheimer’s and found an association with these indicators. In 2022, Ryan Powell, the lead author of that study, published further findings that neighborhood disadvantage was connected with having more neurofibrillary tangles and amyloid plaques, the main pathological features of Alzheimer's disease.
As of yet, little is known about the biological processes behind this, says Powell, director of data science at the Center for Health Disparities Research at the University of Wisconsin School of Medicine and Public Health. “We know the association but not the direct causal pathway.”
The corroborative findings keep coming. In a Nature study published a few months after Powell’s study, every social determinant investigated affected Alzheimer’s risk except for marital status. The links were highest for income, education, and occupational status.
Clinical trials on new Alzheimer’s medications get all the headlines but preventing dementia through policy and public health interventions should not be underestimated.
The potential for prevention is significant. One in three older adults dies with Alzheimer's or another dementia—more than breast and prostate cancers combined. Further, a 2020 report from the Lancet Commission determined that about 40 percent of dementia cases could theoretically be prevented or delayed by managing the risk factors that people can modify.
Take inactivity. Older adults who took 9,800 steps daily were half as likely to develop dementia over the next 7 years, in a 2022 JAMA study. Hearing loss, another risk factor that can be managed, accounts for about 9 percent of dementia cases.
Clinical trials on new Alzheimer’s medications get all the headlines but preventing dementia through policy and public health interventions should not be underestimated. Simply slowing the course of Alzheimer’s or delaying its onset by five years would cut the incidence in half, according to the Global Council on Brain Health.
Minorities Hit the Hardest
The World Health Organization defines SDOH as “conditions in which people are born, work, live, and age, and the wider set of forces and systems shaping the conditions of daily life.”
Anyone who exists on processed food, smokes cigarettes, or skimps on sleep has heightened risks for dementia. But minority groups get hit harder. Older Black Americans are twice as likely to have Alzheimer’s or another form of dementia as white Americans; older Hispanics are about one and a half times more likely.
This is due in part to higher rates of diabetes, obesity, and high blood pressure within these communities. These diseases are linked to Alzheimer’s, and SDOH factors multiply the risks. Blacks and Hispanics earn less income on average than white people. This means they are more likely to live in neighborhoods with limited access to healthy food, medical care, and good schools, and suffer greater exposure to noise (which impairs hearing) and air pollution—additional risk factors for dementia.
Related Reading: The Toxic Effects of Noise and What We're Not Doing About it
Plus, when Black people are diagnosed with dementia, their cognitive impairment and neuropsychiatric symptom are more advanced than in white patients. Why? Some African-Americans delay seeing a doctor because of perceived discrimination and a sense they will not be heard, says Carl V. Hill, chief diversity, equity, and inclusion officer at the Alzheimer’s Association.
Misinformation about dementia is another issue in Black communities. The thinking is that Alzheimer’s is genetic or age-related, not realizing that diet and physical activity can improve brain health, Hill says.
African Americans are severely underrepresented in clinical trials for Alzheimer’s, too. So, researchers miss the opportunity to learn more about health disparities. “It’s a bioethical issue,” Hill says. “The people most likely to have Alzheimer’s aren’t included in the trials.”
The Cure: Systemic Change
People think of lifestyle as a choice but there are limitations, says Muniza Anum Majoka, a geriatric psychiatrist and assistant professor of psychiatry at Yale University, who published an overview of SDOH factors that impact dementia. “For a lot of people, those choices [to improve brain health] are not available,” she says. If you don’t live in a safe neighborhood, for example, walking for exercise is not an option.
Hill wants to see the focus of prevention shift from individual behavior change to ensuring everyone has access to the same resources. Advice about healthy eating only goes so far if someone lives in a food desert. Systemic change also means increasing the number of minority physicians and recruiting minorities in clinical drug trials so studies will be relevant to these communities, Hill says.
Based on SDOH impact research, raising education levels has the most potential to prevent dementia. One theory is that highly educated people have a greater brain reserve that enables them to tolerate pathological changes in the brain, thus delaying dementia, says Majoka. Being curious, learning new things and problem-solving also contribute to brain health, she adds. Plus, having more education may be associated with higher socioeconomic status, more access to accurate information and healthier lifestyle choices.
New Strategies
The chasm between what researchers know about brain health and how the knowledge is being applied is huge. “There’s an explosion of interest in this area. We’re just in the first steps,” says Powell. One day, he predicts that physicians will manage Alzheimer’s through precision medicine customized to the patient’s specific risk factors and needs.
Raina Croff, assistant professor of neurology at Oregon Health & Science University School of Medicine, created the SHARP (Sharing History through Active Reminiscence and Photo-imagery) walking program to forestall memory loss in African Americans with mild cognitive impairment or early dementia.
Participants and their caregivers walk in historically black neighborhoods three times a week over six months. A smart tablet provides information about “Memory Markers” they pass, such as the route of a civil rights march. People celebrate their community and culture while “brain health is running in the background,” Croff says.
Photos and memory prompts engage participants in the SHARP program.
OHSU/Kristyna Wentz-Graff
The project began in 2015 as a pilot study in Croff’s hometown of Portland, Ore., expanded to Seattle, and will soon start in Oakland, Calif. “Walking is good for slowing [brain] decline,” she says. A post-study assessment of 40 participants in 2017 showed that half had higher cognitive scores after the program; 78 percent had lower blood pressure; and 44 percent lost weight. Those with mild cognitive impairment showed the most gains. The walkers also reported improved mood and energy along with increased involvement in other activities.
It’s never too late to reap the benefits of working your brain and being socially engaged, Majoka says.
In Milwaukee, the Wisconsin Alzheimer’s Institute launched the The Amazing Grace Chorus® to stave off cognitive decline in seniors. People in early stages of Alzheimer’s practice and perform six concerts each year. The activity provides opportunities for social engagement, mental stimulation, and a support network. Among the benefits, 55 percent reported better communication at home and nearly half of participants said they got involved with more activities after participating in the chorus.
Private companies are offering intervention services to healthcare providers and insurers to manage SDOH, too. One such service, MyHello, makes calls to at-risk people to assess their needs—be it food, transportation or simply a friendly voice. Having a social support network is critical for seniors, says Majoka, noting there was a steep decline in cognitive function among isolated elders during Covid lockdowns.
About 1 in 9 Americans age 65 or older live with Alzheimer’s today. With a surge in people with the disease predicted, public health professionals have to think more broadly about resource targets and effective intervention points, Powell says.
Beyond breakthrough pills, that is. Like Dorothy in Kansas discovering happiness was always in her own backyard, we are beginning to learn that preventing Alzheimer’s is in our reach if only we recognized it.
Last minute holiday gifts for the bio-inspired
“Merry Christmas! Isn’t it fun to say Merry Christmas to everyone? Time for a party and presents and things that make children happy and give their hearts wings!” go the lyrics of the popular Christmas poem. But adults (of various religions) need their gifts this time of year, too. For the biologically inspired big children, the process of finding the right fit can be daunting. To inform your choices in both conventional and unconventional ways, Leaps.org is presenting a roundup of the coolest bio-products related to health, nutrition, gaming, lifestyle and more.
AYO Circadian Light Therapy Wearable
We don’t hear it tick, but we have our own clock inside our body–more precisely, circadian clocks. Our cells contain tiny molecular clocks that keep track of our circadian rhythms, or our sleep and metabolism pattern and activity levels, on a daily basis. Chronic circadian disruptions can lead to sleep disorders, poor energy levels, weight gain, lousy mood, and sped-up aging, as well as increased risk for every “modern” disease out there, from diabetes to cancer.
Now, high-tech glasses have been developed that attempt to mimic the benefits of sunlight. In the morning and afternoon, these glasses shed blue light into your eyes to stimulate the master clock at the base of your brain for less drowsiness. The technology's design draws from an area of research, chronobiology, that received a Nobel Prize in 2017 and has become increasingly active in recent years.
“We have been developing and testing the AYO Circadian Health solution for the past five years in collaboration with some of the world's leading experts and researchers in chronobiology, light therapy and health,” said Alexander Dimitrov, co-creator of AYO. “We have done studies with over 25,000 participants, and over one million light sessions,” Dimotrov continued, partnering with institutions such as Mount Sinai Hospital, City of Hope and the U.S. Department of Defense.
The technology could fundamentally reshape the way we view sleep, health and our daily calendars. And, when connecting to a mobile app, the glasses could minimize circadian disruptions for travelers between conflicting time zones.
($269)
myDNAge Test
It's not easy for many people to break free of their attachment to the concept of chronological age, which counts years by how many times we’ve circled the sun since the day we were born. Society lumps us all into one age bracket according to our date of birth but, lately, research is suggesting that we should do some serious deconditioning. According to these studies, the more accurate measure is your biological age, a measurement based on various biomarkers of the body’s overall health and resilience, regardless of your calendar age.
If you want to find out your “true” biological age, myDNAge is a test that focuses on epigenetics, or patterns of changes in DNA methylation, with some initial research pointing to its accuracy. It offers a snapshot of your epigenetic age as well as key biomarkers related to your metabolism, risk of Alzheimer's and more, according to Xiaojing Yang, group leader of epigenetics at myDNAge. “You can perform tests six to 12 months [apart] to track the impact of lifestyle changes,” Yang said. The kit could be a useful tool both for citizen scientists and biohacking veterans.
($299 for one kit–Use code NEWYEARNEWME to receive 50% off a second kit)
Prairie Sky Yak Cheese
Do you love cheese? Do you love exotic cheese? Do you have an interest in preserving biological and genetic diversity? If you answered yes to all three questions, yak cheese was made for you. This type of cheese typically comes from a free-range yak living 13,000 feet above surface level in the Tibetan Himalayas, a relative of the endangered Wild yak. (North America is home to at least 5,000 registered yaks.)
“When I learned that we had a piece of rare biodiversity to be preserved for future generations, I realized that the yak in North America needed a job,” said Nicole Geijer Porter, president of World Heritage Yak Conservancy (WHYC), an organization formed to protect heritage yak “If an animal cannot be beneficial to the rancher in some way, exclusively as pets and lawn ornaments, they will go extinct. Raised for meat they are often hybridized with cattle to grow bigger and faster, so they will also go extinct,” said Porter, an epigeneticist turned yak herder.
Each slice of cheese and piece of butter supports the genetic testing and tracking of Tibetan yak. (You can become a member of WHYC through the Adopt-A-Yak program). “This project is also of biological importance because of the low methane emission research on yak, and the high nutritional content of the milk and cheese,” said Porter.
As for flavor, the Prairie Sky Yak Gruyere is a semi-hard cheese with a nutty taste sometimes compared to chocolate; Tomme de Savoie is a semi-soft Alpine cheese reminiscent of a washed rind muenster; and the Yak Cheddar is made with yak milk following the classic English recipe from Wells Cathedral, with earthly and pungent flavors.
(Various prices; $59.95 for the Three Yak Cheese Flight Gift Box, $139.95 for the Regional Himalayan Yak Cheddar Gift Basket and more)
Bite Toothpaste Bits
The price of a healthy smile is steep. Each year over one billion plastic toothpaste tubes are thrown out, over 50 Empire State Buildings worth of these tubes end up in landfills or oceans, and many animals suffer and die each year in cruel tests for improving oral care in people.
Sustainable oral care is both an act of self-love and giving back to the environment. Bite is a toothpaste that boasts about its green practices for a reason: it uses recyclable glass bottles with aluminum lids that break down into sand after they’ve been used. For shipping, Bite uses kraft envelopes padded with recycled and compostable newspapers, and its boxes are made of fully recycled, corrugated cardboard and sealed with paper tape. Bite refills come in 100% home compostable pouches every four months (still no plastic).
Sustainability aside, there may be an element of fun to Bite – as you brush, a mint foam forms “like magic,” the company claims.
Fractional Laser Treatment for Skin
The environment is hard on our skin: from ultraviolet rays to pollution, a constant oxidative war is waged upon it, leading to loss of collagen and damage to the barrier function of the skin. A fractional laser treatment is a type of laser skin resurfacing procedure that essentially traumatizes the skin – in a good way - through subjecting a small area of it to tiny amounts of laser energy. The laser penetrates the second layer of skin, the dermis, leading to skin exfoliation, which stimulates collagen and elastin production.
The treatment may help with soothing acne scarring, correcting uneven skin tone and texture, and reducing wrinkles and fine lines, sun damage and age spots. Recent research suggests the fractional laser can help with improving skin elasticity and reducing the amount and depth of wrinkles, though there’s little to no evidence for any benefits for eyebags, dark circles, discolorations within the eye area and water retention.
(Typically, a single fractional laser treatment costs $750 for a small area, $1500 for a full facial treatment, and $2000 for full face.)
Gadgets and Apps to Measure Your Heart Rate Variability
Heart rate variability may sound like a condition that requires immediate medical treatment, but the more you have of it, the better for your health. Although you may think of the heart as a steadily beating metronome, there are actually small differences in the amount of time between each beat. These differences are called HRV, and having more HRV has been linked to better fitness and fewer diseases.
HRV is easy to measure with a range of gadgets on the market, including Fitbits and Oura Rings. Which product floats your boat is a matter of personal preference, but the Polar H10 chest strap offers some advantages. For example, you can measure your HRV with the Polar H10 while walking around, unlike some devices that require you to stay still while taking a reading.
Plus, the Polar sensor pairs with free apps such as Elite HRV that are great for tracking how your HRV changes over time. "HRV really helps you gauge if you're moving in a positive or negative direction" with your health, says Jason Moore, the CEO and founder of Elite HRV and Spren. Have fun experimenting over the holidays with different lifestyle habits that are associated with higher HRV, some studies show, such as intermittent fasting, regular exercise and just getting more sleep.
($89 for the Polar H10, $0 for the Elite HRV app)
FoodMarble AIRE2
Its predecessor, FOODMarble AIRE1 was a pocket-size breath-testing device that measured hydrogen on the breath. More hydrogen means less digestion, and the AIRE1 used advanced breathalyzer technology to figure out what exactly is going on with the gut. Now, the company has launched FoodMarble AIRE2, which also measures methane alongside with hydrogen. High levels of methane in the body may cause abdominal pain, bloating and constipation, cirrhosis of the liver and chronic pancreatitis. The AIRE2 also comes with haptic feedback to make it easier to use.
Research suggests that these breath tests are valid as at-home diagnostic tools for many digestive conditions. To get the most accurate results, though, it’s important to closely follow the recommended protocol - for example, you can’t eat or drink anything for 10 to 12 hours before the test.
($229)
Adventurist Backpack’s Classic Backpack
The Classic backpack is a perfect option for life science aficionados who enjoy getting outside and exploring in nature. Padding in the front and back provides extra protection for camera gear, laptop, and other electronics, and it's completely water-resistant so you can get outside in winter weather.
Nobility points: Adventurist Backpack Co. is partnered with national non-profit Feeding America, and every backpack sold helps provide 25 meals to families in need across the U.S.
($65)
This Saves Lives
Speaking of nobility points, you could load your new backpack with a food choice that helps feed others as well. In 2013, actors Kristin Bell, Ryan Devlin, Ravi Patel and Todd Grinnell teamed up to start This Saves Lives, which makes power bars full of vitamins and nutrients, and the company has a unique business model: for every bar you buy, a packet of food is sent to a child in need. In addition to offering essential nutrients, the bars are non-GMO, kosher and gluten-free. Note: This Saves Lives is owned by the same company, GOOD Worldwide, that owns Leaps.org.
(Wild Blueberry & Pistachio bars, $23.99)
NADI X Pants
Even if you’re a yoga zealot enjoying the benefits to your strength, balance and flexibility, chances are you're performing the movements sort of askew. Wearable technology wants to improve your yoga posture and these sleek yoga pants called NADI X have subtle electronic sensors that track how you place your hands, rotate your hips, and align your back. The leggings use haptic feedback (or vibrations on your skin) to slowly guide you into correct alignment. You can also combine the wearable with an app that contains 40 poses and fitting music. Even if you aren't into yoga, you could use the pants for a perfect stretching session. If you do use it for yoga poses, the pants will “speak” to you, letting out a soothing "om" sound once everything is perfect.
Meta Quest Pro VR headset
When it comes to perfecting virtual reality (VR), the Meta Quest Pro VR headset is one step ahead the rest. In a vibrant 3D virtual space, your Meta avatar has the ability to translate your real-life facial expressions into the virtual realm so the experience can feel more personal, while controllers track your movement and use haptic feedback to translate your hand gestures and finger actions into VR as well. Unlike its Quest 2 headset, Meta markets this Quest Pro headset, which was just released in October, as a great tool for work and business meetings, but you can also use it to play games, watch movies, or download fitness apps or mental-health related apps – some of which are designed to help you get boxing workouts with long-distance friends, fight your fear of heights or meditate in outer space.
Rouge Sur Mesure Custom Lip Color Creator
Beauty and artificial intelligence (AI) complement each other well in the new Yves Saint Laurent lip personalized color – which wants to put the final nail on the coffin of generic lipsticks. This is a lipstick printer at its core. You pair a device to your smartphone and then insert three lipstick cartridges into the base, each of which comes with a color palette (all four could create up to 4,000 lipstick shades). Particularly charming is the fact that you can take a photo of your outfit, and the app will suggest shades that match or clash it.
($299, cartridges $89 each)
Dairy-Free Cream Cheese and Meatless Breakfast Patties
On the environmental front again, meatless patties and dairy-free cream cheese constitute conscientious and delicious choices for vegans, vegetarians and pretty much anyone else. Chicago-based Nature's Fynd is worth checking out. It uses a microbe named Fusarium strain flavolapis, which has origins in an acidic hot spring at Yellowstone National Park.
“We use this remarkable microbe to grow Fy — a nutritional fungi protein that’s made into a wide variety of delicious and sustainable foods,” says Karuna Rawal, Nature’s Fynd CMO. Fy is grown via a breakthrough fermentation process using a fraction of the water, land, and energy compared to traditional protein sources.
It’s a sustainable way to grow food for Earth’s population,” but Nature’s Fynd isn’t just concentrating on Earth. The company recently partnered with NASA to send Fy to space. “As long as there’s an appropriately controlled environment, we can grow Fy anytime, anywhere. It could be a nutritious food source for astronauts on deep space missions," said Rawal.
CBD Oil
Biologically curious people may be especially interested in trying cannabinoid (CBD) oil. CBD is a natural and safe substance found in cannabis, which has been found to tackle anxiety and depression, reduce symptoms of post-traumatic stress disorder, help manage chronic pain and migraines, improve sleep patterns, and keep panic attacks at bay. Kanibi’s Isolate CBD Oil Tincture is a good choice as it is cinnamon-flavored and made in an FDA-inspected facility.
($109--25% off on your first order)
Govee RGBIC Floor Lamp
Another winner for anyone who's been hearing about the health benefits of obeying your circadian rhythms: "RGB" lights, or red-green-blue lights that can be operated by remote control to shine bright blue light during the day and then, with a few touches of your phone, bathe you in warmer, red light to get you ready for bed. Look for RGB bulbs to stick into the light fixtures you already have, or you could opt for the Govee floor lamp that syncs with an app on your phone (or Alexa) for circadian color changing. You can also put it on party mode and watch it shift across 16 million color shades in response to the rhythms and beats of Cuddle Up, Cozy Down Christmas and Hanukkah Oh Hanukkah.
($99)
PackPoint
If you suffer from packing anxiety (or incompetence), an app may take away the pain. PackPoint is an app that builds your packing list according to trip type, activities and weather. You add your trip details, select activities (fancy dinner, business meeting, or even workout are some examples), and PackPoint tells you what you need to bring to your destination. The app is free, but upgrading to Premium for a small fee lets you add your own activities and packing list items.
(Free, Premium Package $2.99)
Eternity Rose
Roses symbolize love, passion, innocence, friendship, and the disarming power of natural beauty. They wilt fast, though, and their spectacle is an unsettling reminder of the fragility of beauty and existence. Unless you dip the rose in 24 karat gold.
The Eternity Rose is put through an intricate three-month process of electroplating, or coating the rose with copper and then with other metals in micro-thin layers. You won’t have to see your flowers sag after a few days because these roses never die. The glitter of gold atop the natural rose (or platinum or silver–whatever you prefer) will fit right in with the Christmas Eve ambiance.
($169 for the gold rose)
Your phone could show if a bridge is about to collapse
In summer 2017, Thomas Matarazzo, then a postdoctoral researcher at the Massachusetts Institute of Technology, landed in San Francisco with a colleague. They rented two cars, drove up to the Golden Gate bridge, timing it to the city’s rush hour, and rode over to the other side in heavy traffic. Once they reached the other end, they turned around and did it again. And again. And again.
“I drove over that bridge 100 times over five days, back and forth,” says Matarazzo, now an associate director of High-Performance Computing in the Center for Innovation in Engineering at the United States Military Academy, West Point. “It was surprisingly stressful, I never anticipated that. I had to maintain the speed of about 30 miles an hour when the speed limit is 45. I felt bad for everybody behind me.”
Matarazzo had to drive slowly because the quality of data they were collecting depended on it. The pair was designing and testing a new smartphone app that could gather data about the bridge’s structural integrity—a low-cost citizen-scientist alternative to the current industrial methods, which aren’t always possible, partly because they’re expensive and complex. In the era of aging infrastructure, when some bridges in the United States and other countries are structurally unsound to the point of collapsing, such an app could inform authorities about the need for urgent repairs, or at least prompt closing the most dangerous structures.
There are 619,588 bridges in the U.S., and some of them are very old. For example, the Benjamin Franklin Bridge connecting Philadelphia to Camden, N.J., is 96-years-old while the Brooklyn Bridge is 153. So it’s hardly surprising that many could use some upgrades. “In the U.S., a lot of them were built in the post-World War II period to accommodate the surge of motorization,” says Carlo Ratti, architect and engineer who directs the Senseable City Lab at Massachusetts Institute of Technology. “They are beginning to reach the end of their life.”
According to the 2022 American Road & Transportation Builders Association’s report, one in three U.S. bridges needs repair or replacement. The Department of Transportation (DOT) National Bridge Inventory (NBI) database reveals concerning numbers. Thirty-six percent of U.S. bridges need repair work and over 78,000 bridges should be replaced. More than 43,500 bridges are rated in poor condition and classified as “structurally deficient” – an alarming description. Yet, people drive over them 167.5 million times a day. The Pittsburgh bridge which collapsed in January this year—only hours before President Biden arrived to discuss the new infrastructure law—was on the “poor” rating list.
Assessing the structural integrity of a bridge is not an easy endeavor. Most of the time, these are visual inspections, Matarazzo explains. Engineers check cracks, rust and other signs of wear and tear. They also check for wildlife—birds which may build nests or even small animals that make homes inside the bridge structures, which can slowly chip at the structure. However, visual inspections may not tell the whole story. A more sophisticated and significantly more expensive inspection requires placing special sensors on the bridge that essentially listen to how the bridge vibrates.
“Some bridges can afford expensive sensors to do the job, but that comes at a very high cost—hundreds of thousands of dollars per bridge per year,” Ratti says.
We may think of bridges as immovable steel and concrete monoliths, but they naturally vibrate, oscillating slightly. That movement can be influenced by the traffic that passes over them, and even by wind. Bridges of different types vibrate differently—some have longer vibrational frequencies and others shorter ones. A good way to visualize this phenomenon is to place a ruler over the edge of a desk and flick it slightly. If the ruler protrudes far off the desk, it will vibrate slowly. But if you shorten the end that hangs off, it will vibrate much faster. It works similarly with bridges, except there are more factors at play, including not only the length, but also the design and the materials used.
The long suspension bridges such as the Golden Gate or Verrazano Narrows, which hang on a series of cables, are more flexible, and their vibration amplitudes are longer. The Golden Gate Bridge can vibrate at 0.106 Hertz, where one Hertz is one oscillation per second. “Think about standing on the bridge for about 10 seconds—that's how long it takes for it to move all the way up and all the way down in one oscillation,” Matarazzo says.
On the contrary, the concrete span bridges that rest on multiple columns like Brooklyn Bridge or Manhattan Bridge, are “stiffer” and have greater vibrational frequencies. A concrete bridge can have a frequency of 10 Hertz, moving 10 times in one second—like that shorter stretch of a ruler.
The special devices that can pick up and record these vibrations over time are called accelerometers. A network of these devices for each bridge can cost $20,000 to $50,000, and more—and require trained personnel to place them. The sensors also must stay on the bridge for some time to establish what’s a healthy vibrational baseline for a given bridge. Maintaining them adds to the cost. “Some bridges can afford expensive sensors to do the job, but that comes at a very high cost—hundreds of thousands of dollars per bridge per year,” Ratti says.
Making sense of the readouts they gather is another challenge, which requires a high level of technical expertise. “You generally need somebody, some type of expert capable of doing the analysis to translate that data into information,” says Matarazzo, which ticks up the price, so doing visual inspections often proves to be a more economical choice for state-level DOTs with tight budgets. “The existing systems work well, but have downsides,” Ratti says. The team thought the old method could use some modernizing.
Smartphones, which are carried by millions of people, contain dozens of sensors, including the accelerometers capable of picking up the bridges’ vibrations. That’s why Matarazzo and his colleague drove over the bridge 100 times—they were trying to pick up enough data. Timing it to rush hour supported that goal because traffic caused more “excitation,” Matarazzo explains. “Excitation is a big word we use when we talk about what drives the vibration,” he says. “When there's a lot of traffic, there's more excitation and more vibration.” They also collaborated with Uber, whose drivers made 72 trips across the bridge to gather data in different cars.
The next step was to clean the data from “noise”—various vibrations that weren’t relevant to the bridge but came from the cars themselves. “It could be jumps in speed, it could be potholes, it could be a bunch of other things," Matarazzo says. But as the team gathered more data, it became easier to tell the bridge vibrational frequencies from all others because the noises generated by cars, traffic and other things tend to “cancel out.”
The team specifically picked the Golden Gate bridge because the civil structural engineering community had studied it extensively over the years and collected a host of vibrational data, using traditional sensors. When the researchers compared their app-collected frequencies with those gathered by 240 accelerometers formerly placed on the Golden Gate, the results were the same—the data from the phones converged with that from the bridge’s sensors. The smartphone-collected data were just as good as those from industry devices.
The study authors estimate that officials could use crowdsourced data to make key improvements that would help new bridges to last about 14 years longer.
The team also tested their method on a different type of bridge—not a suspension one like the Golden Gate, but a concrete span bridge in Ciampino, Italy. There they compared 280 car trips over the bridge to the six sensors that had been placed on the bridge for seven months. The results were slightly less matching, but a larger volume of trips would fix the divergence, the researchers wrote in their study, titled Crowdsourcing bridge dynamic monitoring with smartphone vehicle trips, published last month in Nature Communications Engineering.
Although the smartphones proved effective, the app is not quite ready to be rolled out commercially for people to start using. “It is still a pilot version,” so there’s room for improvement, says Ratti, who co-authored the study. “But on a more optimistic note, it has really low barriers to entry—all you need is smartphones on cars—so that makes the system easy to reach a global audience.” And the study authors estimate that the use of crowdsourced data would result in a new bridge lasting about 14 years longer.
Matarazzo hopes that the app could be eventually accessible for your average citizen scientist to collect the data and supply it to their local transportation authorities. “I hope that this idea can spark a different type of relationship with infrastructure where people think about the data they're collecting as some type of contribution or investment into their communities,” he says. “So that they can help their own department of transportation, their own municipality to support that bridge and keep it maintained better, longer and safer.”
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.