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Taxpayers spend 22% more per patient to support Medicare Advantage – the private alternative to Medicare that promised to cost less

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theconversation.com – Grace McCormack, Postdoctoral researcher of Health Policy and Economics, University of Southern California – 2024-11-26 07:38:00

Grace McCormack, University of Southern California and Erin Duffy, University of Southern California

Medicare Advantage – the commercial alternative to traditional Medicare – is drawing down federal health care funds, costing taxpayers an extra 22% per enrollee to the tune of US$83 billion a year.

Medicare Advantage, also known as Part C, was supposed to save the government money. The competition among private insurance companies, and with traditional Medicare, to manage patient care was meant to give insurance companies an incentive to find efficiencies. Instead, the program’s payment rules overpay insurance companies on the taxpayer’s dime.

We are health care policy experts who study Medicare, including how the structure of the Medicare payment system is, in the case of Medicare Advantage, working against taxpayers.

Medicare beneficiaries choose an insurance plan when they turn 65. Younger people can also become eligible for Medicare due to chronic conditions or disabilities. Beneficiaries have a variety of options, including the traditional Medicare program administered by the U.S. government, Medigap supplements to that program administered by private companies, and all-in-one Medicare Advantage plans administered by private companies.

Commercial Medicare Advantage plans are increasingly popular – over half of Medicare beneficiaries are enrolled in them, and this share continues to grow. People are attracted to these plans for their extra benefits and out-of-pocket spending limits. But due to a loophole in most states, enrolling in or switching to Medicare Advantage is effectively a one-way street. The Senate Finance Committee has also found that some plans have used deceptive, aggressive and potentially harmful sales and marketing tactics to increase enrollment.

Baked into the plan

Researchers have found that the overpayment to Medicare Advantage companies, which has grown over time, was, intentionally or not, baked into the Medicare Advantage payment system. Medicare Advantage plans are paid more for enrolling people who seem sicker, because these people typically use more care and so would be more expensive to cover in traditional Medicare.

However, differences in how people’s illnesses are recorded by Medicare Advantage plans causes enrollees to seem sicker and costlier on paper than they are in real life. This issue, alongside other adjustments to payments, leads to overpayment with taxpayer dollars to insurance companies.

Some of this extra money is spent to lower cost sharing, lower prescription drug premiums and increase supplemental benefits like vision and dental care. Though Medicare Advantage enrollees may like these benefits, funding them this way is expensive. For every extra dollar that taxpayers pay to Medicare Advantage companies, only roughly 50 to 60 cents goes to beneficiaries in the form of lower premiums or extra benefits.

As Medicare Advantage becomes increasingly expensive, the Medicare program continues to face funding challenges.

In our view, in order for Medicare to survive long term, Medicare Advantage reform is needed. The way the government pays the private insurers who administer Medicare Advantage plans, which may seem like a black box, is key to why the government overpays Medicare Advantage plans relative to traditional Medicare.

Paying Medicare Advantage

Private plans have been a part of the Medicare system since 1966 and have been paid through several different systems. They garnered only a very small share of enrollment until 2006.

The current Medicare Advantage payment system, implemented in 2006 and heavily reformed by the Affordable Care Act in 2010, had two policy goals. It was designed to encourage private plans to offer the same or better coverage than traditional Medicare at equal or lesser cost. And, to make sure beneficiaries would have multiple Medicare Advantage plans to choose from, the system was also designed to be profitable enough for insurers to entice them to offer multiple plans throughout the country.

To accomplish this, Medicare established benchmark estimates for each county. This benchmark calculation begins with an estimate of what the government-administered traditional Medicare plan would spend on the average county resident. This value is adjusted based on several factors, including enrollee location and plan quality ratings, to give each plan its own benchmark.

Medicare Advantage plans then submit bids, or estimates, of what they expect their plans to spend on the average county enrollee. If a plan’s spending estimate is above the benchmark, enrollees pay the difference as a Part C premium.

Most plans’ spending estimates are below the benchmark, however, meaning they project that the plans will provide coverage that is equivalent to traditional Medicare at a lower cost than the benchmark. These plans don’t charge patients a Part C premium. Instead, they receive a portion of the difference between their spending estimate and the benchmark as a rebate that they are supposed to pass on to their enrollees as extras, like reductions in cost-sharing, lower prescription drug premiums and supplemental benefits.

Finally, in a process known as risk adjustment, Medicare payments to Medicare Advantage health plans are adjusted based on the health of their enrollees. The plans are paid more for enrollees who seem sicker.

Two sets of stacked boxes sit below a vertical bar labeled Risk-Adjusted Benchmark. A vertical line bisecting the boxes is labelled what Medicare would actually spend on an enrollee in traditional Medicare

The government pays Medicare Advantage plans based on Medicare’s cost estimates for a given county. The benchmark is an estimate from the Centers for Medicare & Medicaid Services of what it would cost to cover an average county enrollee in traditional Medicare, plus adjustments including quartile payments and quality bonuses. The risk-adjusted benchmark also takes into consideration an enrollee’s health.

Samantha Randall at USC, CC BY-ND

Theory versus reality

In theory, this payment system should save the Medicare system money because the risk-adjusted benchmark that Medicare estimates for each plan should run, on average, equal to what Medicare would actually spend on a plan’s enrollees if they had enrolled in traditional Medicare instead.

In reality, the risk-adjusted benchmark estimates are far above traditional Medicare costs. This causes Medicare – really, taxpayers – to spend more for each person who is enrolled in Medicare Advantage than if that person had enrolled in traditional Medicare.

Why are payment estimates so high? There are two main culprits: benchmark modifications designed to encourage Medicare Advantage plan availability, and risk adjustments that overestimate how sick Medicare Advantage enrollees are.

Two sets of stacked boxes with dotted arrows on the left side of each labeled Medicare Advantage Plan Bid sit below vertical bars labeled Benchmark and Risk-Adjusted Benchmark.

High risk-adjusted benchmarks lead to overpayments from the government to the private companies that administer Medicare Advantage plans.

Samantha Randall at USC, CC BY-ND

Benchmark modifications

Since the current Medicare Advantage payment system started in 2006, policymaker modifications have made Medicare’s benchmark estimates less tied to what the plan spends on each enrollee.

In 2012, as part of the Affordable Care Act, Medicare Advantage benchmark estimates received another layer: “quartile adjustments.” These made the benchmark estimates, and therefore payments to Medicare Advantage companies, higher in areas with low traditional Medicare spending and lower in areas with high traditional Medicare spending. This benchmark adjustment was meant to encourage more equitable access to Medicare Advantage options.

In that same year, Medicare Advantage plans started receiving “quality bonus payments” with plans that have higher “star ratings” based on quality factors such as enrollee health outcomes and care for chronic conditions receiving higher bonuses.

However, research shows that ratings have not necessarily improved quality and may have exacerbated racial inequality.

Even before fully taking into account risk adjustment, recent estimates peg the benchmarks, on average, as 8% higher than average traditional Medicare spending. This means that a Medicare Advantage plan’s spending estimate could be below the benchmark and the plan would still get paid more for its enrollees than it would have cost the government to cover those same enrollees in traditional Medicare.

Overestimating enrollee sickness

The second major source of overpayment is health risk adjustment, which tends to overestimate how sick Medicare Advantage enrollees are.

Each year, Medicare studies traditional Medicare diagnoses, such as diabetes, depression and arthritis, to understand which have higher treatment costs. Medicare uses this information to adjust its payments for Medicare Advantage plans. Payments are lowered for plans with lower predicted costs based on diagnoses and raised for plans with higher predicted costs. This process is known as risk adjustment.

But there is a critical bias baked into risk adjustment. Medicare Advantage companies know that they’re paid more if their enrollees seem more sick, so they diligently make sure each enrollee has as many diagnoses recorded as possible.

This can include legal activities like reviewing enrollee charts to ensure that diagnoses are recorded accurately. It can also occasionally entail outright fraud, where charts are “upcoded” to include diagnoses that patients don’t actually have.

In traditional Medicare, most providers – the exception being Accountable Care Organizations – are not paid more for recording diagnoses. This difference means that the same beneficiary is likely to have fewer recorded diagnoses if they are enrolled in traditional Medicare rather than a private insurer’s Medicare Advantage plan. Policy experts refer to this phenomenon as a difference in “coding intensity” between Medicare Advantage and traditional Medicare.

Human figure with arrows to two boxes. Left box has two plus symbols labelled  recorded diagnoses and one dollar sign. Right box has five symbols and three dollar signs.

The same person is likely to be documented with more illnesses if they enroll in Medicare Advantage rather than traditional Medicare – and cost taxpayers more money.

Samantha Randall at USC, CC BY-ND

In addition, Medicare Advantage plans often try to recruit beneficiaries whose health care costs will be lower than their diagnoses would predict, such as someone with a very mild form of arthritis. This is known as “favorable selection.”

The differences in coding and favorable selection make beneficiaries look sicker when they enroll in Medicare Advantage instead of traditional Medicare. This makes cost estimates higher than they should be. Research shows that this mismatch – and resulting overpayment – is likely only going to get worse as Medicare Advantage grows.

Where the money goes

Some of the excess payments to Medicare Advantage are returned to enrollees through extra benefits, funded by rebates. Extra benefits include cost-sharing reductions for medical care and prescription drugs, lower Part B and D premiums, and extra “supplemental benefits” like hearing aids and dental care that traditional Medicare doesn’t cover.

Medicare Advantage enrollees may enjoy these benefits, which could be considered a reward for enrolling in Medicare Advantage, which, unlike traditional Medicare, has prior authorization requirements and limited provider networks.

However, according to some policy experts, the current means of funding these extra benefits is unnecessarily expensive and inequitable.

It also makes it difficult for traditional Medicare to compete with Medicare Advantage.

Traditional Medicare, which tends to cost the Medicare program less per enrollee, is only allowed to provide the standard Medicare benefits package. If its enrollees want dental coverage or hearing aids, they have to purchase these separately, alongside a Part D plan for prescription drugs and a Medigap plan to lower their deductibles and co-payments.

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Medicare Advantage plans offer extras, but at a high cost to the Medicare system – and taxpayers. Only 50-60 cents of a dollar spent is returned to enrollees as decreased costs or increased benefits.

AP Photo/Pablo Martinez Monsivais

The system sets up Medicare Advantage plans to not only be overpaid but also be increasingly popular, all on the taxpayers’ dime. Plans heavily advertise to prospective enrollees who, once enrolled in Medicare Advantage, will likely have difficulty switching into traditional Medicare, even if they decide the extra benefits are not worth the prior authorization hassles and the limited provider networks. In contrast, traditional Medicare typically does not engage in as much direct advertising. The federal government only accounts for 7% of Medicare-related ads.

At the same time, some people who need more health care and are having trouble getting it through their Medicare Advantage plan – and are able to switch back to traditional Medicare – are doing so, according to an investigation by The Wall Street Journal. This leaves taxpayers to pick up care for these patients just as their needs rise.

Where do we go from here?

Many researchers have proposed ways to reduce excess government spending on Medicare Advantage, including expanding risk adjustment audits, reducing or eliminating quality bonus payments or using more data to improve benchmark estimates of enrollee costs. Others have proposed even more fundamental reforms to the Medicare Advantage payment system, including changing the basis of plan payments so that Medicare Advantage plans will compete more with each other.

Reducing payments to plans may have to be traded off with reductions in plan benefits, though projections suggest the reductions would be modest.

There is a long-running debate over what type of coverage should be required under both traditional Medicare and Medicare Advantage. Recently, policy experts have advocated for introducing an out-of-pocket maximum to traditional Medicare. There have also been multiple unsuccessful efforts to make dental, vision, and hearing services part of the standard Medicare benefits package.

Although all older people require regular dental care and many of them require hearing aids, providing these benefits to everyone enrolled in traditional Medicare would not be cheap. One approach to providing these important benefits without significantly raising costs is to make these benefits means-tested. This would allow people with lower incomes to purchase them at a lower price than higher-income people. However, means-testing in Medicare can be controversial.

There is also debate over how much Medicare Advantage plans should be allowed to vary. The average Medicare beneficiary has over 40 Medicare Advantage plans to choose from, making it overwhelming to compare plans. For instance, right now, the average person eligible for Medicare would have to sift through the fine print of dozens of different plans to compare important factors, such as out-of-pocket maximums for medical care, coverage for dental cleanings, cost-sharing for inpatient stays, and provider networks.

Although millions of people are in suboptimal plans, 70% of people don’t even compare plans, let alone switch plans, during the annual enrollment period at the end of the year, likely because the process of comparing plans and switching is difficult, especially for older Americans.

MedPAC, a congressional advising committee, suggests that limiting variation in certain important benefits, like out-of-pocket maximums and dental, vision and hearing benefits, could help the plan selection process work better, while still allowing for flexibility in other benefits. The challenge is figuring out how to standardize without unduly reducing consumers’ options.

The Medicare Advantage program enrolls over half of Medicare beneficiaries. However, the $83-billion-per-year overpayment of plans, which amounts to more than 8% of Medicare’s total budget, is unsustainable. We believe the Medicare Advantage payment system needs a broad reform that aligns insurers’ incentives with the needs of Medicare beneficiaries and American taxpayers.

This article is part of an occasional series examining the U.S. Medicare system.

Past articles in the series:

Medicare vs. Medicare Advantage: sales pitches are often from biased sources, the choices can be overwhelming and impartial help is not equally available to allThe Conversation

Grace McCormack, Postdoctoral researcher of Health Policy and Economics, University of Southern California and Erin Duffy, Research Scientist and Director of Research Training in Health Policy and Economics, University of Southern California

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The Conversation

AI was everywhere in 2024’s elections, but deepfakes and misinformation were only part of the picture

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theconversation.com – Bruce Schneier, Adjunct Lecturer in Public Policy, Harvard Kennedy School – 2024-12-02 07:37:00

AI played many roles in 2024’s elections.

AP Photo/Paul Vernon

Bruce Schneier, Harvard Kennedy School and Nathan Sanders, Harvard University

It’s been the biggest year for elections in human history: 2024 is a “super-cycle” year in which 3.7 billion eligible voters in 72 countries had the chance to go the polls. These are also the first AI elections, where many feared that deepfakes and artificial intelligence-generated misinformation would overwhelm the democratic processes. As 2024 draws to a close, it’s instructive to take stock of how democracy did.

In a Pew survey of Americans from earlier this fall, nearly eight times as many respondents expected AI to be used for mostly bad purposes in the 2024 election as those who thought it would be used mostly for good. There are real concerns and risks in using AI in electoral politics, but it definitely has not been all bad.

The dreaded “death of truth” has not materialized – at least, not due to AI. And candidates are eagerly adopting AI in many places where it can be constructive, if used responsibly. But because this all happens inside a campaign, and largely in secret, the public often doesn’t see all the details.

Connecting with voters

One of the most impressive and beneficial uses of AI is language translation, and campaigns have started using it widely. Local governments in Japan and California and prominent politicians, including India Prime Minister Narenda Modi and New York City Mayor Eric Adams, used AI to translate meetings and speeches to their diverse constituents.

Even when politicians themselves aren’t speaking through AI, their constituents might be using it to listen to them. Google rolled out free translation services for an additional 110 languages this summer, available to billions of people in real time through their smartphones.

Other candidates used AI’s conversational capabilities to connect with voters. U.S. politicians Asa Hutchinson, Dean Phillips and Francis Suarez deployed chatbots of themselves in their presidential primary campaigns. The fringe candidate Jason Palmer beat Joe Biden in the American Samoan primary, at least partly thanks to using AI-generated emails, texts, audio and video. Pakistan’s former prime minister, Imran Khan, used an AI clone of his voice to deliver speeches from prison.

Perhaps the most effective use of this technology was in Japan, where an obscure and independent Tokyo gubernatorial candidate, Takahiro Anno, used an AI avatar to respond to 8,600 questions from voters and managed to come in fifth among a highly competitive field of 56 candidates.

‘AI Steve’ was an AI persona who ran for office in the 2024 U.K. election.

Nuts and bolts

AIs have been used in political fundraising as well. Companies like Quiller and Tech for Campaigns market AIs to help draft fundraising emails. Other AI systems help candidates target particular donors with personalized messages. It’s notoriously difficult to measure the impact of these kinds of tools, and political consultants are cagey about what really works, but there’s clearly interest in continuing to use these technologies in campaign fundraising.

Polling has been highly mathematical for decades, and pollsters are constantly incorporating new technologies into their processes. Techniques range from using AI to distill voter sentiment from social networking platforms – something known as “social listening” – to creating synthetic voters that can answer tens of thousands of questions. Whether these AI applications will result in more accurate polls and strategic insights for campaigns remains to be seen, but there is promising research motivated by the ever-increasing challenge of reaching real humans with surveys.

On the political organizing side, AI assistants are being used for such diverse purposes as helping craft political messages and strategy, generating ads, drafting speeches and helping coordinate canvassing and get-out-the-vote efforts. In Argentina in 2023, both major presidential candidates used AI to develop campaign posters, videos and other materials.

In 2024, similar capabilities were almost certainly used in a variety of elections around the world. In the U.S., for example, a Georgia politician used AI to produce blog posts, campaign images and podcasts. Even standard productivity software suites like those from Adobe, Microsoft and Google now integrate AI features that are unavoidable – and perhaps very useful to campaigns. Other AI systems help advise candidates looking to run for higher office.

Fakes and counterfakes

And there was AI-created misinformation and propaganda, even though it was not as catastrophic as feared. Days before a Slovakian election in 2023, fake audio discussing election manipulation went viral. This kind of thing happened many times in 2024, but it’s unclear if any of it had any real effect.

In the U.S. presidential election, there was a lot of press after a robocall of a fake Joe Biden voice told New Hampshire voters not to vote in the Democratic primary, but that didn’t appear to make much of a difference in that vote. Similarly, AI-generated images from hurricane disaster areas didn’t seem to have much effect, and neither did a stream of AI-faked celebrity endorsements or viral deepfake images and videos misrepresenting candidates’ actions and seemingly designed to prey on their political weaknesses.

Russian intelligence services aimed to use AI to influence U.S. voters, but it’s not clear whether they had much success.

AI also played a role in protecting the information ecosystem. OpenAI used its own AI models to disrupt an Iranian foreign influence operation aimed at sowing division before the U.S. presidential election. While anyone can use AI tools today to generate convincing fake audio, images and text, and that capability is here to stay, tech platforms also use AI to automatically moderate content like hate speech and extremism. This is a positive use case, making content moderation more efficient and sparing humans from having to review the worst offenses, but there’s room for it to become more effective, more transparent and more equitable.

There is potential for AI models to be much more scalable and adaptable to more languages and countries than organizations of human moderators. But the implementations to date on platforms like Meta demonstrate that a lot more work needs to be done to make these systems fair and effective.

One thing that didn’t matter much in 2024 was corporate AI developers’ prohibitions on using their tools for politics. Despite market leader OpenAI’s emphasis on banning political uses and its use of AI to automatically reject a quarter-million requests to generate images of political candidates, the company’s enforcement has been ineffective and actual use is widespread.

The genie is loose

All of these trends – both good and bad – are likely to continue. As AI gets more powerful and capable, it is likely to infiltrate every aspect of politics. This will happen whether the AI’s performance is superhuman or suboptimal, whether it makes mistakes or not, and whether the balance of its use is positive or negative. All it takes is for one party, one campaign, one outside group, or even an individual to see an advantage in automation.The Conversation

Bruce Schneier, Adjunct Lecturer in Public Policy, Harvard Kennedy School and Nathan Sanders, Affiliate, Berkman Klein Center for Internet & Society, Harvard University

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Fossilized footprints reveal 2 extinct hominin species living side by side 1.5 million years ago

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theconversation.com – Anna K. Behrensmeyer, Senior Research Geologist and Curator of Vertebrate Paleontology, Smithsonian Institution – 2024-11-28 13:01:00

Excavating the new trackway site, with footprints from hominins, birds and other animals visible in foreground.
Neil Roach

Anna K. Behrensmeyer, Smithsonian Institution; Kevin Hatala, Chatham University, and Purity Kiura, National Museums of Kenya

Human footprints stir the imagination. They invite you to follow, to guess what someone was doing and where they were going. Fossilized footprints preserved in rock do the same – they record instants in the lives of many different extinct organisms, back to the earliest creatures that walked on four feet, 380 million years ago.

Discoveries in eastern Africa of tracks made by hominins – our ancient relatives – are telling paleontologists like ourselves about the behavior of hominin species that walked on two feet and resembled us but were not yet human like we are today. Our new research focuses on footprints that amazingly record two different species of hominins walking along the same Kenyan lakeshore at the same time, roughly 1.5 million years ago.

Studying ancient tracks like these fills in exciting pieces of the human evolution story because they provide evidence for hominin behavior and locomotion that scientists cannot learn from fossilized bones.

Finding first fossilized footprints in Kenya

The first discovery of tracks of early hominins in Kenya’s Lake Turkana region happened by chance in 1978. A team led by one of us (Behrensmeyer) and paleoecologist Léo Laporte was exploring the geology and fossils of the rich paleontological record of East Turkana. We focused on documenting the animals and environments represented in one “time slice” of widespread sediments deposited about 1.5 million years ago.

man squats on excavation surface, brushing with paintbrush
Kimolo Mulwa at the site of the first hominin footprint discovery in 1978. Deep, sand-filled depressions to his left show hippopotamus tracks in cross section.
Anna K. Behrensmeyer

We collected fossils from the surface and dug geological step trenches to document the sediment layers that preserved the fossils. The back wall of one of the trenches showed deep depressions in a layer of solidified mud that we thought might be hippo tracks. We were curious about what they looked like from the top down – what scientists call the “plan view” – so we decided to expose 1 square meter of the footprint surface next to the trench.

When I returned from more fossil bone surveys, Kimolo Mulwa, one of the expert Kenyan field assistants on the project, had carefully excavated the top of the mudstone layer and there was a broad smile on his face. He said, “Mutu!” – meaning “person” – and pointed to a shallow humanlike print in among the deep hippo tracks.

indentations on flat sediment surface
The excavated surface shows the hominin trackway along with footprints of hippos, a large bird and other animals. For the photo, scientists filled the hominin tracks and a few other footprints with dark sand so they would stand out against the light-colored sediment.
Anna K. Behrensmeyer

I could hardly believe it, but, yes, a humanlike footprint was clearly recognizable on the excavated surface. And there were more hominin tracks, coming our way out of the strata. It was awe-inspiring to realize we were connecting with a moment in the life of a hominin that walked here 1½ million years ago.

We excavated more of the surface and eventually found seven footprints in a line, showing that the hominin had walked eastward out of softer mud onto a harder, likely shallower surface. At one point the individual’s left foot had slipped into a deep hippo print and the hominin caught itself on its right foot to avoid falling – we could see this clearly along the trackway.

Comparison of a fossil footprint and a modern one
Comparison of the best-preserved 1978 hominin track, left, with a modern track (women’s size 7) made by Behrensmeyer on the muddy shoreline of Lake Turkana. The white objects inside the fossil footprint are calcified fillings of worm burrows or roots that formed in the sediment after the track was buried.
Anna K. Behrensmeyer

Even today on the shore of modern Lake Turkana, it’s easy to slip into hippo prints, especially if the water is a bit cloudy. We joked about being sorry our hominin track-maker didn’t fall on its hands, or face, so we could have a record of those parts, too.

Another set of tracks

Over four decades later, in 2021, paleontologist Louise Leakey and her Kenyan research team were excavating hominin fossils discovered in the same area when team member Richard Loki uncovered a portion of another hominin trackway. Leakey invited one of us (Hatala) and paleoanthropologist Neil Roach to excavate and study the new trackway, because of our experience working on other hominin footprint sites.

3D image of footprints pressed into a surface
A 3D image of part of the 2021 excavated surface made by photogrammetry, which shows the tracks of two hominin species crossing.
Kevin Hatala

The team, including 10 expert Kenyan field researchers led by Cyprian Nyete, excavated the surface and documented the tracks with photogrammetry – a method for 3D imaging. This is the best way to collect track surfaces because the sediments are not hard enough – what geologists call lithified – to remove from the ground safely and take to a museum.

The newly discovered tracks were made approximately 1.5 million years ago. They occur at an earlier stratigraphic level than the ones we found in 1978 and are about a hundred thousand years older, based on dating of volcanic deposits in the East Turkana strata.

aerial view of about a dozen people standing in a curve on a rocky bare landscape
Research team members along the perimeter of the ancient footprint trackway.
Louise N. Leakey

Who was passing through?

These footprints are especially exciting because careful anatomical and functional analysis of their shapes shows that two different kinds of hominins made tracks on the same lakeshore, within hours to a few days of each other, possibly even within minutes!

We know the footprints were made very close together in time because experiments on the modern shoreline of Lake Turkana show that a muddy surface suitable for preserving clear tracks doesn’t last long before being destroyed by waves or cracked by exposure to the Sun.

fossilized indentations of footprints receding into distance on sandy-looking ground
A trackway of footprints scientists hypothesize were created by a Paranthropus boisei individual.
Neil T. Roach

This is the first time ever that scientists have been able to say that Homo erectus and Paranthropus boisei – one our likely ancestor and the other a more distant relative – actually coexisted at the same time and place. Along with many different species of mammals, they were both members of the ancient community that inhabited the Turkana Basin.

Not only that, but with the new tracks as references, our analyses suggest that other previously described hominin tracks in the same region indicate that these two hominins coexisted in this area of the Turkana Basin for at least 200,000 years, repeatedly leaving their footprints in the shallow lake margin habitat.

Other animals left tracks there as well – giant storks, smaller birds such as pelicans, antelope and zebra, hippos and elephants – but hominin tracks are surprisingly common for a land-based species. What were they doing, returning again and again to this habitat, when other primates, such as baboons, apparently did not visit the lakeshore and leave tracks there?

silhouette of a tree with circles for about 20 hominin species, showing their relationships
The track-making species Homo erectus and Paranthropus boisei are on two different branches of the hominin family tree.
Smithsonian Human Origins Program, modified by author from original artwork

These footprints provoke new thoughts and questions about our early relatives. Were they eating plants that grew on the lakeshore? Some paleontologists have proposed this possibility for the robust Paranthropus boisei because the chemistry of its teeth indicate a specific herbivorous diet of grasslike and reedlike plants. The same chemical tests on teeth of Homo erectus – the ancestral species to Homo sapiens – show a mixed diet that likely included animal protein as well as plants.

The lake margin habitat offered food in the form of reeds, freshwater bivalves, fish, birds and reptiles such as turtles and crocodiles, though it could have been dangerous for bipedal primates 4 or 5 feet (1.2 to 1.5 meters) tall. Even today, people living along the shore occasionally are attacked by crocodiles, and local hippos can be aggressive as well. So, whatever drew the hominins to the lakeshore must have been worth some risk.

For now it’s impossible to know exactly how the two species interacted. New clues about their behavior could be revealed with future excavations of more trackway surfaces. But it is fascinating to imagine these two hominin “cousins” being close neighbors for hundreds of thousands of years.

people carrying water buckets at a sandy construction site in open landscape
Construction of the Ileret footprint site museum, with Daasanach women carrying water for mixing concrete.
National Museums of Kenya Audio Visual

Ancient footprints you can visit

Earlier excavations of hominin trackways near a village called Ileret, 25 miles (40 km) to the north of our new site, are being developed as a museum through a project by the National Museums of Kenya. The public, the local Daasanach people, educational groups and tourists will be able to see a large number of 1.5-million-year-old hominin footprints on one excavated surface.

That layer preserves tracks of at least eight hominin individuals, and we now believe they represent members of both Homo erectus and Paranthropus boisei. Among these is a subset of individuals, all about the same adult size, who were moving in the same direction and appear to have been traveling as a group along the lake margin.

The museum built over the track site is designed to prevent erosion of the site and to protect it from seasonal rains. A community outreach and education center associated with the museum aims to engage local educational groups and young people in learning and teaching others about this exceptional record of human prehistory preserved in their backyard. The new site museum is scheduled to open in January 2025.The Conversation

Anna K. Behrensmeyer, Senior Research Geologist and Curator of Vertebrate Paleontology, Smithsonian Institution; Kevin Hatala, Associate Professor of Biology, Chatham University, and Purity Kiura, Chief Research Scientist in Archaeology and Heritage, National Museums of Kenya

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208 million Americans are classified as obese or overweight, according to new study synthesizing 132 data sources

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theconversation.com – Marie Ng, Affiliate Associate Professor of Global Health, University of Washington – 2024-11-27 07:50:00

Overweight and obesity rates are rising in all age ranges across the U.S.

Mohamed Rida ROKI/iStock via Getty Images Plus

Marie Ng, University of Washington

Nearly half of adolescents and three-quarters of adults in the U.S. were classified as being clinically overweight or obese in 2021. The rates have more than doubled compared with 1990.

Without urgent intervention, our study forecasts that more than 80% of adults and close to 60% of adolescents will be classified as overweight or obese by 2050. These are the key findings of our recent study, published in the journal The Lancet.

Synthesizing body mass index data from 132 unique sources in the U.S., including national and state-representative surveys, we examined the historical trend of obesity and the condition of being overweight from 1990 to 2021 and forecast estimates through 2050.

For people 18 and older, the condition health researchers refer to as “overweight” was defined as having a body mass index, or BMI, of 25 kilograms per square meter (kg/m²) to less than 30 kg/m² and obesity as a BMI of 30 kg/m² or higher. For those younger than 18, we based definitions on the International Obesity Task Force criteria.

This study was conducted by the Global Burden of Disease Study 2021 U.S. Obesity Forecasting Collaborator Group, which comprises over 300 experts and researchers specializing in obesity.

There are ways to combat the trends, such as making activity fun and leading by example.

Why it matters

The U.S. already has one of the highest rates of obesity and people who are overweight globally. Our study estimated that in 2021, a total of 208 million people in the U.S. were medically classified as overweight or obese.

Obesity has slowed health improvements and life expectancy in the U.S. compared with other high-income nations. Previous research showed that obesity accounted for 335,000 deaths in 2021 alone and is one of the most dominant and fastest-growing risk factors for poor health and early death. Obesity increases the risk of diabetes, heart attack, stroke, cancer and mental health disorders.

The economic implications of obesity are also profound. A report by Republican members of the Joint Economic Committee of the U.S. Congress, published in 2024, predicted that obesity-related health care costs will rise to US$9.1 trillion over the next decade.

The rise in childhood and adolescent obesity is particularly concerning, with the rate of obesity more than doubling among adolescents ages 15 to 24 since 1990. Data from the National Health and Nutrition Examination Survey revealed that nearly 20% of children and adolescents in the U.S. ages 2 to 19 live with obesity.

By 2050, our forecast results suggest that 1 in 5 children and 1 in 3 adolescents will experience obesity. The increase in obesity among children and adolescents not only triggers the early onset of chronic diseases but also negatively affects mental health, social interactions and physical functioning.

What other research is being done

Our research highlighted substantial geographical disparities in overweight and obesity prevalence across states, with southern U.S. states observing some of the highest rates.

Other studies on obesity in the United States have also underscored significant socioeconomic, racial and ethnic disparities. Previous studies suggest that Black and Hispanic populations exhibit higher obesity rates compared with their white counterparts. These disparities are further exacerbated by systemic barriers, including discrimination, unequal access to education, health care and economic inequities.

Another active area of research involves identifying effective obesity interventions, including a recent study in Seattle demonstrating that taxation on sweetened beverages reduced average body mass index among children. Various community-based studies also investigated initiatives aimed at increasing access to physical activity and healthy foods, particularly in underserved areas.

Clinical research has been actively exploring new anti-obesity medications and continuously monitoring the effectiveness and safety of current medications.

Furthermore, there is a growing body of research examining technology-driven behavioral interventions, such as mobile health apps, to support weight management. However, whether many of these programs are scalable and sustainable is not yet clear. This gap hinders the broader adoption and adaptation of effective interventions, limiting their potential impact at the population level.

What’s next

Our study forecasts trends in overweight and obesity prevalence over the next three decades, from 2022 to 2050, assuming no action is taken.

With the advent of new-generation anti-obesity medications, obesity management could change substantially. However, the extent of this impact will depend on factors such as cost, accessibility, coverage, long-term efficacy and variability in individual responses. Future research will need to leverage the most up-to-date evidence.

The Research Brief is a short take on interesting academic work.The Conversation

Marie Ng, Affiliate Associate Professor of Global Health, University of Washington

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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