Taking the stairs is one way to boost the intensity of day-to-day activities like errands. For people who don’t exercise, such brief vigorous actions were linked to a lower risk of death compared with those whose days didn’t include these activity bursts.
Making day-to-day activities more vigorous for a few minutes — such as briefly stepping up the pace of a walk — could offer people who don’t exercise some of the health benefits that exercisers enjoy.
That’s according to a new study of roughly 25,000 adults who reported no exercise in their free time. Those who incorporated three one- to two-minute bursts of intense activity per day saw a nearly a 40 percent drop in the risk of death from any cause compared with those whose days didn’t include such activity. The risk of death from cancer also fell by nearly 40 percent, and the risk of death from cardiovascular disease dropped almost 50 percent, researchers report online December 8 in Nature Medicine .
In a comparison with around 62,000 people who exercised regularly, including runners, gym-goers and recreational cyclists, the mortality risk reduction was similar.
“This study adds to other literature showing that even short amounts of activity are beneficial,” says Lisa Cadmus-Bertram, a physical activity epidemiologist at the University of Wisconsin–Madison, who was not involved in the research. “So many people are daunted by feeling that they don’t have the time, money, motivation, transportation, etc. to go to a gym regularly or work out for long periods of time,” she says. “The message we can take is that it is absolutely worth doing what you can.”
Emmanuel Stamatakis, an epidemiologist at the University of Sydney, and his colleagues analyzed a subset of records from the UK Biobank, a biomedical database containing health information on half a million people in the United Kingdom. The study’s non-exercising participants — more than half of whom were women and were 62 years old on average — had worn movement-tracking devices for a week.
Over an average seven years of follow-up, for those whose days included three to four bursts of activity, the mortality rate was 4.2 deaths from any cause per 1,000 people for one year. For those with no activity bursts, it was 10.4 deaths per 1,000 people for one year.
The researchers were looking for bursts of vigorous activity that met a definition determined in a laboratory study, including reaching at least 77 percent of maximum heart rate and at least 64 percent of maximum oxygen consumption. In real life, the signs that someone has reached the needed intensity level are “an increase in heart rate and feeling out of breath” in the first 15 to 30 seconds of an activity, Stamatakis says.
Regular daily activities offer several opportunities for these vigorous bursts, he says. “The simplest one is maximizing walking pace for a minute or two during any regular walk.” Other options, he says, include carrying grocery bags to the car or taking the stairs. “The largest population health gains will be realized by finding ways to get the least physically active people to move a little more.”
Aimee Cunningham is the biomedical writer. She has a master’s degree in science journalism from New York University.
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A New Figure for the Cosmic Speed Limit – Science News , December 2, 1972
A group at the National Bureau of Standards at Boulder, Colo., now reports an extremely accurate [speed of light] measurement using the wavelength and frequency of a helium-neon laser.… The result gives the speed of light as 299,792.4562 kilometers per second.
That 1972 experiment measured the two-way speed of light, or the average speed of photons that traveled from their source to a reflective surface and back. The result, which still holds up, helped scientists redefine the standard length of the meter ( SN: 10/22/83, p. 263 ). But they weren’t done putting light through its paces. In the late 1990s and early 2000s, photons set a record for slowest measured speed of light at 17 meters per second and froze in their tracks for one-thousandth of a second ( SN: 1/27/01, p. 52 ). For all that success, one major hurdle remains: directly testing the one-way speed of light. The measurement, which many scientists say is impossible to make, could resolve the long-standing question of whether the speed of light is uniform in all directions.
Nikk Ogasa is a staff writer who focuses on the physical sciences for Science News . He has a master’s degree in geology from McGill University, and a master’s degree in science communication from the University of California, Santa Cruz.
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2022 was the year many people decided the coronavirus pandemic had ended.
President Joe Biden said as much in an interview with 60 Minutes in September. “The pandemic is over,” he said while strolling around the Detroit Auto Show. “We still have a problem with COVID. We’re still doing a lot of work on it. But the pandemic is over.”
His evidence? “No one’s wearing masks. Everybody seems to be in pretty good shape.”
But the week Biden’s remarks aired, about 360 people were still dying each day from COVID-19 in the United States. Globally, about 10,000 deaths were recorded every week. That’s “10,000 too many, when most of these deaths could be prevented,” the World Health Organization Director-General Tedros Adhanom Ghebreyesus said in a news briefing at the time. Then, of course, there are the millions who are still dealing with lingering symptoms long after an infection.
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Those staggering numbers have stopped alarming people, maybe because those stats came on the heels of two years of mind-boggling death counts ( SN Online: 5/18/22 ). Indifference to the mounting death toll may reflect pandemic fatigue that settled deep within the public psyche, leaving many feeling over and done with safety precautions.
“We didn’t warn people about fatigue,” says Theresa Chapple-McGruder, an epidemiologist in the Chicago area. “We didn’t warn people about the fact that pandemics can last long and that we still need people to be willing to care about yourselves, your neighbors, your community.”
Public health agencies around the world, including in Singapore and the United Kingdom, reinforced the idea that we could “return to normal” by learning to “live with COVID.” The U.S. Centers for Disease Control and Prevention’s guidelines raised the threshold for case counts that would trigger masking ( SN Online: 3/3/22 ). The agency also shortened suggested isolation times for infected people to five days , even though most people still test positive for the virus and are potentially infectious to others for several days longer ( SN Online: 8/19/22 ).
The shifting guidelines bred confusion and put the onus for deciding when to mask, test and stay home on individuals. In essence, the strategy shifted from public health — protecting your community — to individual health — protecting yourself.
Doing your part can be exhausting, says Eric Kennedy, a sociologist specializing in disaster management at York University in Toronto. “Public health is saying, ‘Hey, you have to make the right choices every single moment of your life.’ Of course, people are going to get tired with that.”
Doing the right thing — from getting vaccinated to wearing masks indoors — didn’t always feel like it paid off on a personal level. As good as the vaccines are at keeping people from becoming severely ill or dying of COVID-19, they were not as effective at protecting against infection. This year, many people who tried hard to make safe choices and had avoided COVID-19 got infected by wily omicron variants ( SN Online: 4/22/22 ). People sometimes got reinfected — some more than once ( SN: 7/16/22 & 7/30/22, p. 8 ).
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Those infections may have contributed to a sense of futility. “Like, ‘I did my best. And even with all of that work, I still got it. So why should I try?’ ” says Kennedy, head of a Canadian project monitoring the sociological effects of the COVID-19 pandemic.
Getting vaccinated, masking and getting drugs or antibody treatments can reduce the severity of infection and may cut the chances of infecting others. “We should have been talking about this as a community health issue and not a personal health issue,” Chapple-McGruder says. “We also don’t talk about the fact that our uptake [of these tools] is nowhere near what we need” to avoid the hundreds of daily deaths.
A lack of data about how widely the coronavirus is still circulating makes it difficult to say whether the pandemic is ending. In the United States, the influx of home tests was “a blessing and a curse,” says Beth Blauer, data lead for the Johns Hopkins University Coronavirus Resource Center . The tests gave an instant readout that told people whether they were infected and should isolate. But because those results were rarely reported to public health officials, true numbers of cases became difficult to gauge, creating a big data gap ( SN Online: 5/27/22 ).
About 80 percent of the U.S. population got the first COVID-19 vaccine dose and close to 70 percent completed the primary series. The updated booster, made available in September, had only made it into the arms of 12 percent of people age 5 and older as of November 24.
The flow of COVID-19 data from many state and local agencies also slowed to a trickle. In October, even the CDC began reporting cases and deaths weekly instead of daily . Altogether, undercounting of the coronavirus’s reach became worse than ever.
“We’re being told, ‘it’s up to you now to decide what to do,’ ” Blauer says, “but the data is not in place to be able to inform real-time decision making.”
With COVID-19 fatigue so widespread, businesses, governments and other institutions have to find ways to step up and do their part, Kennedy says. For instance, requiring better ventilation and filtration in public buildings could clean up indoor air and reduce the chance of spreading many respiratory infections, along with COVID-19. That’s a behind-the-scenes intervention that individuals don’t have to waste mental energy worrying about, he says.
The bottom line: People may have stopped worrying about COVID-19, but the virus isn’t done with us yet. “We have spent two-and-a-half years in a long, dark tunnel, and we are just beginning to glimpse the light at the end of that tunnel. But it is still a long way off,” WHO’s Tedros said. “The tunnel is still dark, with many obstacles that could trip us up if we don’t take care.” If the virus makes a resurgence, will we see it coming and will we have the energy to combat it again?
Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
As a nonprofit news organization, we cannot do it without you.
Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. Invest in quality science journalism by donating today.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
It’s been more than two years since the first long COVID patients called attention to their condition . But researchers are still unable to answer basic questions about it, such as how vaccination impacts one’s chances of long-term symptoms or which groups of people are most at-risk, thanks to gaping holes in long COVID data.
Some data gaps originated early in the pandemic. For instance, in spring 2020, people who lacked a travel history to China or didn’t have typical flulike symptoms were unable to get a PCR test to confirm they were infected. So when some of those people later developed long COVID, their initial illness had not been logged in medical records — making it difficult for them to get care and keeping them off most researchers’ radar.
Other data gaps reveal long-standing problems in how the medical system treats complex, chronic diseases. Doctors weren’t looking out for long-term symptoms, despite warnings from experts in other postviral diseases. And some of the most common long COVID symptoms, such as a dramatic worsening of health after exertion, lack a standard code for documentation in medical charts, making them hard to track.
Filling in those gaps is becoming increasingly crucial. Studies suggest that between 10 and 30 percent of people with COVID-19 may experience long-term symptoms, ranging from a simple loss of smell and taste to debilitating cognitive challenges. In the United States alone, that adds up to millions of people who, long after the pandemic ends, may still be dealing with the consequences of the disease.
The urgency of supporting these patients has led to a push for greater collaboration, new technologies and perhaps most important of all, an openness to really listen to long COVID patients, believing in and using their experiences to shape future research.
To inform potential treatments, researchers aim to better characterize the causes of and variations in long COVID’s wide range of symptoms. Currently, long COVID tends to be defined broadly ( SN: 7/29/22 ). The U.S. Centers for Disease Control and Prevention characterizes it as a “wide range of ongoing health problems” that can last for months after infection with SARS-CoV-2, the virus responsible for COVID-19.
The electronic health records that researchers use to study long COVID aren’t comprehensive, however, due to gaps in the data. Records often focus disproportionately on people who could get a PCR or antibody test, were hospitalized and had predominantly respiratory symptoms, says Lisa McCorkell, a public policy researcher and cofounder of the Patient-Led Research Collaborative , a group of long COVID patients who also have research experience.
What’s more, records “do not document all of the symptoms the patient experiences,” she says. And for many patients, information about different symptoms can be spread across different healthcare systems, making it difficult for researchers to connect the dots.
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“A long COVID diagnosis can mean so many different things in your physiology are going wrong,” says David Putrino, director of rehabilitation innovation at the Mount Sinai healthcare system in New York City and leader of one of the first labs to focus on long COVID. More comprehensive tracking of patients’ symptoms, he says, is crucial to better understand how long COVID presents itself and document how it impacts patients’ lives.
To achieve this goal, experts say, future data collection must be designed collaboratively. Coordination between patients and researchers helps ensure studies are asking the right questions, while coordination between experts with different specialties promotes multidisciplinary, creative approaches to a condition that impacts every organ system in the body. Coordination between research groups in different locations is also important for producing inclusive datasets.
New studies currently in early phases across the United States provide models for how scientists can work with patients and across specialties to investigate long COVID, learning from mistakes made earlier in the pandemic. The results of this work could inform strategies for patients to manage their symptoms and lead to potential treatments.
Some of the most influential research on long COVID so far has come from patients themselves, including a 2021 study from the Patient-Led Research Collaborative that documents more than 200 potential symptoms .
“Patients know the right questions to ask to properly document their experience,” McCorkell says. This can include which symptoms are studied, how data are collected from patients and how groups of patients are compared.
For example, one common flaw in research design is that potential long COVID patients might be included in a study’s control group (that is, with the assumption that they do not have the condition) because they lack a positive test result or “do not have the exact symptoms a study defines as being long COVID,” McCorkell explains. Since many long COVID patients — especially those who got sick early in the pandemic — lack positive test results, such a control group can skew study findings because researchers are comparing two groups of people that, potentially, both include patients with long COVID.
To avoid these problems, researchers can solicit feedback from patients during all parts of the scientific process. The Patient-Led Research Collaborative required this type of engagement for applicants to a $5-million research fund run by the collaborative: The winning projects , announced on November 22, were reviewed by a panel of patient experts and will incorporate further patient feedback throughout the research process.
Putrino’s lab is taking a similar approach in setting up a new clinic focused on long COVID and other complex, chronic illnesses. The lab has a “lived experience advisory board” that responds to questions ranging from how the clinic’s waiting room should be set up to how healthcare workers ask patient survey questions, Putrino says.
Surveys have become a particularly valuable tool in long COVID research, filling the gaps left by electronic health records. Health records are “the clunkiest part of this research,” says Arjun Venkatesh, a patient-reported outcomes researcher at Yale University who is investigating COVID-19’s long-term impacts . While new web applications and legislation have made it easier for patients to access their medical records, researchers still face many technical and data security barriers to connecting datasets from different health systems.
Venkatesh and his colleagues use surveys to collect basic information, such as a patient’s vaccine record, as well as metrics that typically wouldn’t be in an electronic health record, such as their fatigue levels over time. In setting up these surveys, it’s important to solicit input from patients, Venkatesh and others say. Filling out a survey could trigger common long COVID symptoms like brain fog or post-exertion pain and fatigue. Responsible researchers ask a small group of patient volunteers to test surveys before they are widely released.
Input from patients is also crucial in designing clinical trials for long COVID, says Julia Moore Vogel, a program director at the Scripps Research Translational Institute in San Diego. People living with the condition have spent time reading studies, comparing notes and testing out symptom management techniques. “There’s actually a decent amount of anecdotal data we can use to inform trials,” she says.
Anecdotal data inspired a study that Vogel, a long-hauler herself, is starting. She is aiming to enroll 5,000 patients who will test how well a wearable device helps them manage their symptoms, using a technique called pacing. Some Garmin health trackers have a feature called “body battery,” which combines several measurements to determine the user’s capacity for exertion. Vogel and other long-haulers use this feature to monitor their activity, stopping to rest when their “battery” gets low. Her new study aims to test the strategy on a larger scale.
The number of people impacted by long COVID is unprecedented. But the condition shares many characteristics with other complex, chronic diseases that arise after infections and affect multiple organ systems, such as myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS . These conditions have historically received limited research funding even though they impact millions of people — a problem attributed in part to the diseases’ inability to fit into a specific medical specialty, says Jaime Seltzer, director of scientific and medical outreach at the ME/CFS advocacy group #MEAction, which is based in Santa Monica, Calif.
Funding from the National Institutes of Health, for example, is allocated to research groups through the agency’s topic-focused institutes and centers. “Every disease is supposed to neatly and nicely fit into these categories,” Seltzer says. “And if it doesn’t, everyone goes, ‘It’s not my problem.’” Conditions like ME/CFS and long COVID also are not taught in medical schools, leading to a general lack of awareness among doctors about how to properly diagnose them, she says, which results in incomplete datasets.
To push back against this fractured system, doctors and researchers need to collaborate across specialties, experts say. Scientists with different types of expertise are starting to work together to design comprehensive studies, share data and educate each other about new techniques. The Long COVID Research Consortium is one such group: Researchers with different specialties are investigating the condition’s underlying biology, with data shared across the participating teams.
“We’re going to be setting up our own data-sharing platform,” says consortium member Richard Scheuermann, director of informatics at the J. Craig Venter Institute in La Jolla, Calif. Data from studies of long COVID patients’ microbiomes, immune systems, lungs and other areas will all be in “the same database,” he says, enabling research that connects the different body systems.
Collaboration between scientists in different places is also crucial to producing research that reflects a diverse patient population. One example is the National Institutes of Health’s RECOVER initiative to learn about the long-term health effects of COVID-19 ( SN: 10/24/22 ).
The initiative’s adult study has recruited about 10,000 people from 53 sites all over the United States and Puerto Rico . But Putrino would like to see the federal government go further by recruiting more patients, collaborating more closely with patient advocacy groups, educating providers and integrating research with efforts to directly help long-haulers, such as aid with disability benefits applications .
Create “a set of common data elements that every site collects, so that every site around the country can contribute to a national registry of people with long COVID,” Putrino says. Such a registry, similar to existing registries for cancer patients , would help researchers better understand the different potential subtypes of long COVID and provide a large population ready to volunteer for clinical trials.
As researchers recruit for large studies of long COVID, they should reach out to communities that are less educated about the condition, says Dona Kim Murphey, a physician, neuroscientist and long-hauler based in Houston. “How do you reach the folks who don’t even know to come to you?” she asks. Public education campaigns about long COVID — combined with easier access to healthcare for people facing long-term symptoms — can contribute to more comprehensive patient datasets ( SN: 11/3/22 ).
Some long COVID researchers are using new technology to better understand the condition, such as wearable devices, survey apps and machine learning for analysis. But models for comprehensive, collaborative research that includes all patients with a complex condition don’t need to be reinvented. As an example, Seltzer points to a 2014 CDC initiative to study autism , in which 11 sites across the country worked together to diagnose children while simultaneously educating clinicians about autism.
“They basically had diagnostic experts in autism train other people to become diagnostic experts in autism,” she says. The study is a model in creating an inclusive dataset, while simultaneously enabling a new group of researchers to better study a condition in the future. Seltzer hopes to see federal agencies enable similar large-scale studies for long COVID and related conditions.
As some long COVID patients enter their fourth year with the condition and more people continue to get infected, moving toward impactful clinical trials is a top priority for scientists. “Design research in a way that’s going to be most effective to the end users, who are the patients,” says Vogel, the Scripps researcher. Going forward, this research model could be valuable for other complex diseases, too.
Betsy Ladyzhets is a freelance science writer and data journalist based in Brooklyn, N.Y.
Science News produces award-winning journalism, and Society for Science, our parent organization, provides programs to make sure that every young person can strive to become an engineer or scientist. Make a gift today to support all we do, including our outreach and equity STEM Programs and world-class science research competitions.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Pet owners may have a new reason to reach for the kibble.
Dry cat and dog food tends to be better for the environment than wet food, veterinary nutritionist Vivian Pedrinelli of the University of São Paulo in Brazil and colleagues report. Their analysis of more than 900 hundred pet diets shows that nearly 90 percent of calories in wet chow comes from animal sources. That’s roughly double the share of calories from animal ingredients in dry food.
The team factored in the cost of different pet food ingredients across several environmental measures. The findings, described November 17 in Scientific Reports , suggest that wet food production uses more land and water and emits more greenhouse gases than dry food.
Scientists already knew that meat-heavy human diets drive greenhouse gas emissions (SN: 5/5/22) . But when it comes to environmental sustainability, “we shouldn’t ignore pet food,” says Peter Alexander, an economist at the University of Edinburgh who was not involved in the work.
Just how much various pet foods impact the environment isn’t clear, Alexander says. Commercial cat and canine fares aren’t typically made from prime cuts of meat. Instead, the ingredient lists often include animal byproducts — the gristle and bits people aren’t likely to eat anyway.
How to calculate the carbon cost of these leftovers is an ongoing debate, says Gregory Okin, an environmental scientist at the University of California, Los Angeles who was not involved with the study.
Some argue that the byproducts in pet food are essentially free, since they come from animals already raised for human consumption. Others note that any calories require energy and therefore incur an environmental cost. Plus, animal ingredients in pet food might not be just scraps. If they contain even a small amount of human-edible meat, that could add up to a big impact.
Knowing that there’s an environmental difference between moist morsels and crunchier cuisines could be helpful for eco-conscious pet owners, Okin says. Having that info handy at the grocery store is “super important when people are making decisions,” he adds. “There are consumers who want to pay attention.”
Meghan Rosen is a staff writer who reports on the life sciences for Science News . She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.
Science News produces award-winning journalism, and Society for Science, our parent organization, provides programs to make sure that every young person can strive to become an engineer or scientist. Make a gift today to support all we do, including our outreach and equity STEM Programs and world-class science research competitions.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
For decades, chemicals that make life easier — your eggs slide out of the frying pan, stains don’t stick to your sofa, rain bounces off your jackets and boots — have been touted as game changers for our busy modern lives. “Better things for better living … through chemistry,” was the optimistic slogan coined by DuPont, the company that invented the widely used chemical coating Teflon .
But this better living has come at a cost that is getting new attention. These chemicals — dubbed forever chemicals for their ability to last in the environment — are proving to have a lasting impact on human health. A growing body of research links the group of chemicals broadly known as PFAS, short for per- and polyfluoroalkyl substances, to conditions from unhealthy blood lipid levels to pregnancy complications to cancer.
Alarm about the health impacts of these chemicals has sparked a recent flurry of action from U.S. public health and regulatory officials. Warning that PFAS pose a greater health risk than previously thought, the U.S. Environmental Protection Agency in June dramatically lowered its recommended safe levels of the chemicals in drinking water.
“The updated advisory levels are based on new science, including more than 400 recent studies which indicate that negative health effects may occur at extremely low levels, much lower than previously understood,” Radhika Fox, assistant administrator of the EPA’s Office of Water, said in June at the Third National PFAS Conference , held in Wilmington, N.C.
Soon after, the National Academies of Sciences, Engineering and Medicine released the first clinical guidelines quantifying blood concentration levels of PFAS that could put someone’s health at risk. The 300-page report urges clinicians to recommend regular blood tests for anyone exposed to high levels of the chemicals and to provide information on how to limit exposure, such as installing special filters known to reduce PFAS in drinking water.
In the United States alone, by one measure, the tally in medical care costs and lost productivity from PFAS exposure linked to five medical conditions adds up to at least $5.5 billion annually , researchers at New York University reported July 26 in Exposure and Health . Those conditions include low birth weight, childhood obesity, hypothyroidism in women, and kidney and testicular cancers.
“We only looked at two of the more than 9,000 chemicals in the PFAS family, so we’re just seeing the tip of an iceberg,” says Leonardo Trasande, a pediatrician and environmental health expert at NYU Langone Health.
Among those most at risk of exposure are firefighters: PFAS make protective gear more water resistant, and the chemicals are found in a widely used fire suppressant foam. But most people have some measurable level of PFAS in their bodies, according to the U.S. Centers for Disease Control and Prevention. Exposure typically comes from ingesting PFAS-contaminated drinking water or food grown in soil treated with fertilizers made from sewage contaminated with the chemicals ( SN: 11/24/18, p. 18 ). An estimated 2,854 locations across the United States have PFAS contamination.
“People and communities have had significant exposure to these chemicals. If they can ID that they are in an area of significant exposure, they should seek testing through their usual source of care,” says Ned Calonge, an epidemiologist at the Colorado School of Public Health in Aurora who chaired the committee that wrote the National Academies report. The committee linked PFAS exposure to a slightly different list of conditions than the NYU team, finding “sufficient evidence” linking PFAS to four conditions: poor antibody response to vaccination, abnormally high cholesterol levels, decreased infant and fetal growth, and kidney cancer. Evidence was “suggestive” for breast and testicular cancers, as well as thyroid problems and ulcerative colitis, an inflammatory bowel disease.
The report calls for more research into the health effects of PFAS, noting gaps in evidence on everything from neurological issues to bone density. These chemicals have a wide range of impacts on multiple systems in the body, Calonge says. And they’re “ubiquitous in the environment.”
PFAS have been produced in the United States since the 1940s. Because they are good at repelling oil and water, holding up at high temperatures and reducing friction, the chemicals became useful for a vast array of products, including carpeting, upholstery, food packaging and even dental floss. Yet, relatively few of the 9,000 or so versions of these synthetic chemicals have been studied for their toxicologic effects.
Many PFAS are now recognized as endocrine disruptors, chemical compounds that interfere with the normal functioning of the endocrine, or hormonal, system. But PFAS have other effects that can boost cancer risk , such as weakened immunity, excessive cell growth and altered gene activity. One study found a greater than twofold increase in kidney cancer risk between people with the highest versus lowest blood levels of one common PFAS called perfluorooctanoic acid, or PFOA, researchers reported in 2021 in the Journal of the National Cancer Institute .
A newer generation of PFAS was assumed to be safer because the chemicals are less likely to accumulate in the body . But these newer compounds are structurally similar to the older ones and can be just as harmful to health as their cousins, Trasande says. These newer molecules “are increasingly being associated with diseases like gestational diabetes. We’re just starting to see the bigger problem that might be at play.”
The EPA’s new drinking water advisory aims to tackle both old and new PFAS. It targets two of the earlier and most commonly found kinds of PFAS in the environment: PFOA and perfluorooctane sulfonic acid, or PFOS. The advisory reduces the level of drinking water contamination below which adverse health effects are not expected from 70 parts per trillion to 0.004 and 0.02 ppt, respectively. Those levels are based on routine exposure to them over a lifetime.
The EPA’s health advisory also provided the first-ever recommendations on two of the newer kinds of PFAS: hexafluoropropylene oxide dimer acid and HFPO ammonium salt, collectively known as GenX chemicals, and perfluorobutane sulfonic acid, or PFBS. The agency set the drinking water safety threshold at 10 ppt for GenX chemicals and 2,000 ppt for PFBS. These newer chemicals have similar persistence in the environment, the agency states.
A National Academies panel found sufficient and suggestive evidence that PFAS boost risk for several ailments. * in adults, † in children
Consumers can ask their municipal water provider for data on PFAS testing in their area. Testing is becoming more common, and providers should be able to list which PFAS they test for. Private wells can be contaminated with PFAS if they are near manufacturers that produce or use the chemicals, as well as airfields where PFAS are used for firefighting, firefighting training areas and some waste disposal sites. People with private wells near one of these facilities can get their water tested. The EPA is giving grants to help underserved small and disadvantaged communities provide household water quality testing and comply with drinking water regulations.
Because there are limited available data on the health effects of the newer generation of chemicals, the NYU and National Academies reports focused on the impacts of older PFAS.
First, the NYU team examined PFAS chemicals in blood samples obtained from roughly 5,000 adults and children who participated in the U.S. National Health and Nutrition Examination Survey. Then, based on earlier studies linking PFAS to certain diseases and models that estimate medical costs and lost worker productivity for these illnesses, the team came up with its PFAS price tag.
Childhood obesity, the largest contributor to the overall economic toll of PFAS exposure, costs about $2.7 billion a year, the team estimates, followed by hypothyroidism in women at $1.26 billion. When the researchers considered other PFAS-linked diseases beyond the top five, such as endometriosis, obesity in adults and pneumonia in children, the estimated economic burden rose to as much as $63 billion annually.
The National Academies report focused in part on how to curb that toll by providing testing guidelines to clinicians to detect high levels of PFAS in the body and try to reduce exposure.
The report provides the first clinical guidelines on how to assess a person’s disease risk. A person with a PFAS blood concentration of less than 2 nanograms per milliliter doesn’t have to worry. But for patients with blood concentrations between 2 and 20 ng/mL, clinicians should screen for conditions like unhealthy levels of fat in the blood, which can lead to heart problems. Such screening is especially important for people more vulnerable to the effects of PFAS exposure, like children, pregnant people and those who are immunocompromised. For anyone who tests above 20 ng/mL, the report encourages routine screenings for some cancers, thyroid problems and ulcerative colitis.
“For almost 20 years, we’ve been able to measure PFAS in people’s blood, but there was no guidance to say what [those measurements] mean,” says National Academies report coauthor Jane Hoppin, who heads the Center for Human Health and the Environment at North Carolina State University in Raleigh. “For the first time, this actually sets some ranges, some guidance for what could be levels of concern, and what kinds of health follow-up might be appropriate.”
She hopes that the recommendations will increase testing availability and make both doctors and patients more aware of these chemicals and their health risks. The report also encourages doctors to work with their patients to figure out where they are being exposed to PFAS and how to mitigate those risks, by cutting down on PFAS-containing products and filtering water.
Activated carbon filters, found in some countertop or pitcher filters, don’t remove PFAS as completely as reverse osmosis filters, researchers at Duke University and North Carolina State reported in 2020. The National Academies report offers a link to NSF, a testing organization that offers technical details on which filters actually filter out PFAS.
Efforts like reducing PFAS in drinking water could help. While EPA’s health advisories are recommendations and not enforceable, Trasande is pleased that the agency acted quickly, particularly on newer chemicals like GenX. But he argues that in light of what we already know and are continuing to learn about the disease burden caused by these chemicals, PFAS should undergo more testing before they are approved. Better yet, they should be regulated by class instead of taking what he calls a whack-a-mole approach.
“Our environmental policy still takes a wait-and-see approach that we should wait 20 to 30 years, which is the time that people take to develop diseases due to chemical exposures,” he says.
Melba Newsome is a freelance writer based in Charlotte, N.C.
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