Health

Is wildfire smoke bad for your health?

Anonymous — Tue, 30 Jun 2026 17:02:41 +0000

Is wildfire smoke bad for your health? Anonymous (not verified) Tue, 06/30/2026 - 11:02

Lisa Marshall

Editor's note: This article was originally published July 12, 2021, and updated June 30, 2026.

Coloradans awoke to hazy skies this week, as smoke from multiple large fires burning across the West deemed air quality “poor” and “unhealthy for sensitive groups” in some regions, according to federal data.

Not long ago, researchers had little understanding of how such smoke impacts human health—if at all, says Colleen Reid, an assistant professor of geography who, in 2008, became one of the first researchers in the country to start studying it.

“At the time, there was a sense that it was ‘natural’ air pollution, and that it was only short-term so it was not as much of a concern as pollution from things like factories, refineries and vehicles,” she said. “What we are realizing now, as these episodes of exposure become more frequent and last longer, is that wildfire smoke can have measurable and potentially lasting health impacts.“

Reid spoke with CU ��ý�� Today about what those impacts are and how we can minimize them.

It seems like smoke is getting worse each summer. Is it?

It is. When I started this work, people collecting data from monitors in Northern California said "disregard anything above 400 micrograms per cubic meter (ug/m3)" because they assumed it was impossible. They thought the monitors were malfunctioning. Now, in some areas of the country, levels have reached the thousands during extreme wildfire smoke events near the fire.

There is now evidence that wildfire smoke is offsetting the gains in air quality that have been achieved by regulating industrial and vehicular emissions under the Clean Air Act.

What is wildfire smoke made of?

It’s a complex mix of gases and solid and liquid particles. From a health perspective, the particles—that dark cloud that you see when you look at the smoke plume—are most concerning. They are so tiny that, unlike larger particles, they don’t get stopped in the trachea or nose when you breathe them in.

When assessing air quality, we tend to focus on PM2.5, particulate matter that is 2.5 microns or smaller in diameter. The smaller the particle, the deeper they get into the lungs, and the more likely they are to get into the bloodstream.

Most particles created during wildfires are 1 micron or smaller, not only affecting respiratory health but potentially having systemic effects—including inflammatory effects. They have found particles in the brains of cadavers, so we also know they can get into the brain.

Is there anything else in there of concern?

Some researchers have also become concerned about hazardous air pollutants such as formaldehyde, benzene and hydrogen cyanide present in wildfire smoke. We also have found these contaminants in ash after wildfires that burn structures, such as the Marshall Fire and the L.A. fires. Ground-level ozone is also a concern, as it is a respiratory irritant and can be formed through chemical reactions of other air pollutants in wildfire smoke.

Is wildfire smoke worse for you than other forms of air pollution?

The case is not yet settled on this.

Some epidemiological studies suggest that PM2.5 found in wildfire smoke is more harmful than other sources of PM2.5, but these findings do not take into account differences in what burned (forest, grassland or human-made materials) or the fact that wildfire smoke is very bad for short periods, whereas other sources of PM2.5 contribute lower levels but regularly throughout the year.

At least one study in mice found that particles in wildfire smoke are more toxic than particles from other sources.

How does wildfire smoke impact short-term health?

Probably everyone exposed to wildfire smoke is impacted in some way, even if they don’t recognize it. They might be a little short of breath or have some heart rate variability or lung function decline. We know that it can cause a sore throat, cough, itchy/watery eyes, congestion and shortness of breath. If you can’t breathe as deeply and get as much oxygen, especially at this altitude, you might feel tired.

For people with pre-existing respiratory disease (such as asthma or emphysema), wildfire smoke can lead to increased need to use medication and, in some cases, needing emergency care. Generally, there are more people who die during wildfire events than would be expected if the wildfire was not there—these are probably individuals who were very sick and the air pollution from the wildfire smoke was the proverbial straw that broke the camel’s back.

Are there longer-term effects?

My own research found that babies whose gestation is during a wildfire event are more likely to be born with a lower birth weight and more likely to be born early. There is also some evidence that wildfire smoke can trigger heart attacks and impact the immune system.

One recent study looking at eight years of data in Montana found that areas with more intense wildfire smoke exposure in the summer had worse flu seasons the following winter. It could be that wildfire smoke irritates the lungs and makes people more susceptible to worse infection upon exposure. Some evidence suggests that areas with worse wildfire smoke may experience more COVID-19 cases or more severe cases of the disease.

Researchers are also studying whether wildfire smoke is affecting metabolic health and cognition.

What should people do on smoky days?

Make sure that your medication is up to date and that you have enough of it.

Use indoor air cleaners and make sure to check the filter on portable air cleaners and on your HVAC system. After just one bad wildfire smoke episode, the filter can be filled with particulates and needs to be changed. Get the highest MERV (minimum efficiency reporting value) rating on your HVAC filter that your system can handle.

On very smoky days, people with pre-existing conditions or those who are more sensitive should wear an N95, KN95 or KF94 mask (good for smaller sizes or children) that fits them well.

What if the fire is really far away? Should I worry?

A study from researchers at Colorado State University found there were more asthma hospitalizations along the Front Range when there was wildfire smoke in the area from the Pacific Northwest than when there was smoke from a local fire.

The difference is likely due to people being more likely to protect themselves when fires are close than when there is only smoke. That means people should take precautions when there is smoke in the area, regardless of how close the fire is.

Should I exercise outdoors when it’s smoky?

That is a challenging question. We know from studies of cyclists that when the air pollution levels are not too high, the benefits of exercise outweigh the risk of air pollution exposure. But when the air quality gets really bad, it is challenging.

I recommend following the guidelines of the air quality index (AQI):

For the average person—curb outdoor exercise when levels exceed an AQI level of 150 or PM2.5 concentrations of 55 micrograms per meter cubed.
For those with pre-existing respiratory or cardiovascular disease—the recommended levels are lower, 100 on the AQI or 35 micrograms per meter cubed PM2.5 concentration.

If you can’t see to the end of your street, that might be a time to curb your outdoor exercise.

Can the smoke get inside?

From research I have done looking at indoor and outdoor PM2.5 in normal times and during wildfire smoke episodes, we see that PM2.5 can infiltrate indoor environments—but this happens less so in newer constructions (which are less leaky or tighter) and those with central HVAC systems. Indoor spaces do protect people from outdoor smoke.

But even with a really tight home, if the air pollution is bad for many days at a time, the smoke will get in. HEPA filters can help a lot. When it is really smoky, try to keep your windows and doors closed. But you also don’t want the indoor temperature to get so high that it is a health threat.

With heat and wildfires happening at the same time, that gets really challenging, especially for people who don’t have air conditioning. Some cities are looking into creating public clean-air shelters with air conditioning and HEPA filters.

CU ��ý�� Today regularly publishes Q&As on news topics through the lens of scholarly expertise and research/creative work. The responses here reflect the knowledge and interpretations of the expert and should not be considered the university position on the issue. All publication content is subject to edits for clarity, brevity and university style guidelines.

With fires blazing across Colorado and surrounding states, many communities are inundated with smoke this week. How does it impact our health? Is it OK to exercise outside? How can we protect ourselves? Wildfire smoke researcher Colleen Reid has answers.

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Overpopulation can impair fertility. New study explains why

Lisa Marshall — Thu, 21 May 2026 12:18:27 +0000

Overpopulation can impair fertility. New study explains why Lisa Marshall Thu, 05/21/2026 - 06:18

Lisa Marshall

Scientists have reported it for decades: Overpopulation can impair reproduction.

Crowded chickens lay fewer eggs. Crowded mice have smaller broods. In humans, several studies have associated increased population density with reduced fertility.

External factors, such as resource scarcity and social influences, undoubtedly play a role. But researchers have long suspected that intrinsic, biological mechanisms may also be at play as an evolutionary tool to keep populations in check.

New CU ��ý�� research, published this month in the journal Nature Communications, identifies one key mechanism.

It found that overcrowded animals secrete a chemical messenger that can damage eggs, impair embryos and cause genetic mutations in offspring for generations to come.

“It has been well documented that population density has a direct and negative impact on human and animal fertility, but the underlying mechanisms have been elusive,” said senior author Ding Xue, professor of molecular, cellular and developmental biology at CU ��ý��. “Our study provides novel insights into how overpopulation can cause various developmental defects, including reduced fertility and increased mortality.”

The study comes as the world population nears 8.3 billion—three times what it was in 1950. Meanwhile, the authors note, birth rates are on the decline. Worldwide, the fertility rate has gone from five births per woman in 1950 to 2.3 births in 2021. According to the World Health Organization, one in six people experience infertility (defined as the inability to achieve a pregnancy after 12 months of trying).

“Overpopulation and crowding stress have emerged as major challenges in contemporary societies, especially in urban cities, where two-thirds of the world population live,” said Xue. “Our study may provide important molecular insights into the underlying health problems that can come with it.”

What radiation and overcrowding have in common

Xue’s team stumbled upon the findings serendipitously while studying a phenomenon known as radiation induced bystander effect (RIBE).

RIBE occurs in cancer patients receiving radiation therapy, when untreated, healthy cells outside a radiated site are also affected and damaged, leading to side effects like hair loss, fatigue and reproductive issues. Due in part to concerns about RIBE, pregnant women are advised to avoid radiation exposure.

In a 2017 study, published in Nature, Xue discovered what drives this bystander effect in the C. elegans worm: Cells stressed by radiation release a protein called cysteine protease related 4 (CPR-4), which travels to other healthy cells around the body and damages their DNA.

Other species across the animal kingdom, including humans and mice, have a similar chemical messenger called Cathepsin B cysteine protease.

Years later, in a follow-up study, Xue’s team noticed that, even in the absence of radiation, if worms lived in extremely crowded conditions, they emitted the protein.

At the molecular level, Xue said, the crowded animals looked a lot like they had been exposed to radiation.

Mutations passed through generations

For the new study, the team compared worms living in various-sized colonies. They found the worms typically didn’t secrete CPR-4, but once their colony exceeded 3,000 individuals, they did. The more overcrowded they were, the more of the enzyme they secreted, and the enzyme damaged their DNA. Experiments in mice showed similar results.

On average, those living in crowded conditions had 87% more genetic mutations in germ cells (reproductive cells). The animals had significantly fewer offspring. Also, the surviving offspring often had visible defects.

Genome sequencing showed some of those genetic mutations were passed on through generations, suggesting that overcrowding may drive genome evolution.

When the researchers silenced the protein in animals, it prevented the adverse effects of crowding. This suggests the enzyme plays a critical role in reproductive problems.

More research is necessary to determine whether the findings have implications for humans and other animals.

Xue has already developed and patented a compound that can inhibit the Cathepsin B cysteine protease enzyme in animals and has a good safety profile.

He believes such inhibitors could someday be used in agriculture, for example, to increase egg or fish production. The findings could also inform new approaches to helping humans struggling to have a family.

Overcrowded animals produce an enzyme that damages DNA in eggs, potentially sabotaging reproduction, new research shows. The findings could inform new approaches for improving fertility in people and animals.

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A crowd of thousands crowds into a Muse concert in Paris. Photo: Creative Commons

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Thousands crowd into a Muse concert in Paris. Credit: Creative Commons

How a CU ��ý�� scientist built a leading aging research program in a gym

Megan M Rogers — Wed, 20 May 2026 19:50:18 +0000

How a CU ��ý�� scientist built a leading aging research program in a gym Megan M Rogers Wed, 05/20/2026 - 13:50

In a new memoir, researcher Doug Seals reflects on building a nationally recognized aging research program inside CU ��ý��'s Carlson Gymnasium.

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Diseases can spread between apartments via shared ventilation, study shows

Lisa Marshall — Tue, 12 May 2026 23:58:11 +0000

Diseases can spread between apartments via shared ventilation, study shows Lisa Marshall Tue, 05/12/2026 - 17:58

Lisa Marshall

In June 2020 COVID-19 swept through this seven-story building in Santander, Spain. A new study shows the virus spread through the ventilation system. Photo credits: David Higuera. Video courtesy: El Pais Newspaper.

Airborne diseases like measles, influenza and COVID-19 can easily spread between units in multifamily buildings via a type of bathroom ventilation system commonly used around the world, new research suggests.

The study, conducted inside an older high-rise in Spain early in the coronavirus pandemic, adds to a growing body of evidence that airborne viruses can spread between separated indoor spaces, transmitting disease without face-to-face contact.

“We tend to think that if we shut the door in our apartment, we are safe and can’t get infected. But our study shows that, depending on the ventilation system in place, that may not be the case,” said senior author Shelly Miller, professor emerita in the Department of Mechanical Engineering at CU ��ý��.

Published in the journal PLOS One on May 12, the research was a collaboration between CU ��ý��, the University of Valencia and the University of Cantabria in Spain, and Concordia University in Canada.

‘The ghost in the room’

The project got its start in Santander, Spain, in June of 2020, just as residents began to emerge from lockdown. Cases had dropped to zero, and people were still masking and social distancing, when residents of a seven-story building got a call from public health officials: Someone on the third floor had tested positive for the SARS CoV2-virus.

The building was locked down again. But soon 15 people across four vertically stacked apartments had contracted COVID-19.

Engineer David Higuera lived in the building with his wife and two small children. They had a hunch that the ventilation shafts connecting bathrooms were to blame.

“I knew that, if what my wife and I suspected was happening, it could have significant scientific implications for public health,” said Higuera, a co-author on the study.

Higuera contacted regional health authorities and the press, but he said he was initially met with “very little interest.”

So he partnered with Miller, a world expert in airborne particles, who was on sabbatical in Spain.

They worked with epidemiologists to genetically sequence samples from infected residents, confirming they likely got it from one another. Then they brought in specialized equipment, shipped from CU ��ý��, to measure airflow and air pressure in the building.

At one point, Higuera placed a plastic bag over the bathroom duct and filmed as it filled with air coming in from other units. In another experiment, the team remotely measured carbon dioxide levels throughout the day in a vacant apartment.

Carbon dioxide is emitted through human breath and wouldn’t be expected to exist at high levels in a vacant space. Yet the apartment was filled with it.

“It was like there was a ghost in the room,” said Higuera.

Team engineers developed a computer simulation to model how virus-laden particles, emitted from breath or flushed toilets, could flow throughout the building under different circumstances.

Ventilation ducts in the bathroom of the Santander building. Courtesy David Higuera.

As with many older buildings across Spain and around the world, the bathrooms weren’t designed to have windows or fans. Instead, they use the “stack effect” in which shared vertical ventilation shafts move air out through vents in the wall, exhausting it through the roof via natural convection.

The study found that shifts in weather could impact air pressure in the shaft, with hotter temperatures pushing air flow back through the vents. Switching on the kitchen exhaust hood could exacerbate the spread, sucking almost all the air from an adjacent bathroom into a nearby apartment within minutes.

“The most plausible transmission route for this outbreak was the bathroom vertical ventilation duct system,” the authors conclude.

Could it happen elsewhere?

The study is not the first to document disease spreading through ventilation systems.

In 2003, during an outbreak of severe acute respiratory syndrome (SARS) in a Hong Kong high-rise, virus-laden particles made their way into a shared ventilation system via a bathroom floor drain, infecting 321 and killing 42 people.

The Santander building was built in 1969, and that type of ventilation system was phased out in Spain in 1975 with new building codes. But roughly one-third of the country’s buildings were built before then.

This type of ventilation is uncommon in the United States today, but similar systems still exist worldwide in older buildings.

“While this is a special building design more common in Spain, it illustrates a broader concern—that even if you are far from the source, if your air is connected, you can still get sick,” said Miller. “This can happen in a multifamily apartment building through the ducts, in a hotel between the hallway and rooms off the hallway, in office buildings between offices or on a cruise ship.”

Notably, Higuera installed a fan in his own bathroom during the pandemic, with a flap that prevented airflow from coming in. No one in his family got sick.

The authors are now calling on officials in Spain to update building standards to assure that older buildings take similar steps to mitigate disease transmission risk. They say architects everywhere should do more to address indoor air quality when designing new buildings.

For individuals wanting to reduce airborne contaminants in their own work or living space, Miller recommends using a high-quality air purifier.

Alberto Garcia, a recent mechanical engineering doctoral graduate from CU ��ý��, contributed to this study.

A detailed analysis of airflow in a high-rise building found a COVID-19 outbreak likely spread via the bathroom ventilation system. The findings have implications for other airborne diseases and for older multifamily buildings around the world.

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Why older adults are turning to weed

Lisa Marshall — Thu, 07 May 2026 16:09:49 +0000

Why older adults are turning to weed Lisa Marshall Thu, 05/07/2026 - 10:09

Lisa Marshall

Older adults are increasingly turning to cannabis to avoid taking pharmaceuticals, or as a “last resort” for pain, sleep, mental health issues and other age-related problems. But they have real concerns about the drug’s potentially intoxicating effects, according to new CU ��ý�� and University of Utah research.

The study was published May 1 in the journal JAMA Network Open.

“For the most part, we found that these folks aren’t really interested in getting high. They just want to feel better,” said senior author Angela Bryan, professor of psychology and neuroscience at CU ��ý��.

Adults age 60 and older constitute the fastest growing demographic of cannabis users in the U.S. Yet previous research shows they often have trouble getting evidence-based advice from their doctors. The authors hope their findings, and more to come later this year from their first-of-a-kind study of older cannabis users, can inform new tools to help people navigate their decisions.

“Older adults would love to be able to talk about this with their primary care providers, but, unfortunately, the typical response they get is either, ‘I don’t know anything about it’ or ‘I can’t make any recommendations,’” said Bryan. “These patients often end up going to a dispensary and talking to a well-meaning 22-year-old budtender who doesn’t have the training to advise a 75-year-old with knee problems.”

The graying weed consumer

Between 2006 and 2013, the prevalence of people over age 65 who used cannabis soared 250% as legalization swept the country. Prevalence has continued to climb since, with 19% of adults ages 50–64 and 6% over 65 now using cannabis.

To understand why, and to explore the unique risks and benefits this group faces, the research team recruited 169 Colorado adults (average age 71) who were not regular cannabis users yet but were interested in trying edibles.

The researchers interviewed each participant at length.

Later, using CU ��ý��’s mobile laboratory, aka Cannavan, the team visited the homes of participants after they had used cannabis and invited them into the van for tests of balance, heart rate, cognition and other measures. (Because cannabis remains illegal at the federal level, such tests cannot take place in a lab on campus.)

Professional research assistants Paige Xiaoying Phillips (left) and Gray MacDonald pose for a photo inside the mobile pharmacology lab, aka the Cannavan, at CU ��ý��.

They found that 57% of older adults sought help for sleep, 50% for pain and 25% for mental health issues. Most were interested in a combination product including THC and CBD. Less than 14% sought THC-dominant products.

Many expressed concern that THC (the main psychoactive ingredient in marijuana) would impair their cognition or motivation (CBD—cannabidiol—does not generally cause intoxication).

“Combination products were perceived to be a ‘Goldilocks’ option,” the authors report.

Some limited evidence suggests that adding CBD to THC can augment a product’s anti-inflammatory properties while reducing some of THC’s intoxicating effects and paranoia, but more research is necessary to know for sure, said Bryan.

Participants often found their way to cannabis after exhausting other options, due to concerns about medication side effects, or because they thought they were already taking too many pills. In the absence of guidance from healthcare providers, they relied on advertising or word-of-mouth claims.

CU ��ý�� Professor Angela Bryan

“We would love to see more conversations happening about this in the healthcare system, where physicians can help guide things,” said first author Rebecca Delaney, an assistant professor of population health sciences at University of Utah Health whose team develops “decision aids” (like pamphlets, videos and interactive websites) to help patients navigate healthcare decisions.

Bryan envisions a day when an older person considering cannabis could plug their ailment, age, other medications they’re on and preferences into a web-based decision aid and get science-backed advice on whether cannabis might help and which kind (CBD, THC or a combination? Edible or flower?).

Since little research has been done on older cannabis users, that advice is hard to come by now.

“At the end of the day, we want to help people make informed decisions,” Bryan said.

Custom cannabis for the older set?

Bryan notes that cannabinoid receptors in the brain and body dwindle with age—which may impact dosing. Some preliminary research suggests older adults may also be more sensitive to certain side effects, such as stomach problems from edibles.

Those with other age-related health problems may need to be more mindful of the impaired balance, elevated heart rate and acute cognitive problems that, according to the team’s preliminary findings, can come with higher levels of THC.

“The worst thing that can happen to an older adult is falling and breaking a hip, so that’s something some people need to consider,” said Bryan.

Forthcoming papers from the study will report how well cannabis worked and its acute and longer-term impacts. For now, Bryan says their work provides valuable insight to the cannabis industry: Tailoring some products to the over-60 set could be a wise idea.

“I think the takeaway for industry would be that this is a demographic that currently is not being very well tailored to,” Bryan said.

People 60 and older constitute the fastest growing group of cannabis users in the U.S. A new study explores why, and what doctors and retailers can do to better serve them.

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6 things CU ��ý�� research has taught us about cannabis

Lisa Marshall — Mon, 20 Apr 2026 18:14:03 +0000

6 things CU ��ý�� research has taught us about cannabis Lisa Marshall Mon, 04/20/2026 - 12:14

Lisa Marshall

It’s Cannabis Awareness Month, and few universities have done as much as CU ��ý�� to advance our scientific understanding of Cannabis sativa.

In 2017, researchers at the Center for Health & Neuroscience, Genes & Environment (CUChange) unveiled the nation’s first mobile laboratory, a.k.a. Cannavan, for studying the plant’s real-time impact on users.

Since cannabis remains illegal at the federal level, university researchers are not permitted to possess or provide commercially available cannabis products for research. The van—now a fleet of three Dodge/Mercedes sprinter vans—gets around that scientific obstacle, enabling research teams to drive to the off-campus home of study subjects who have already consumed their own cannabis products and invite them in for everything from blood and cognitive tests to roadside sobriety tests.

Professional research assistants Paige Xiaoying Phillips (left) and Gray MacDonald pose for a photo inside the mobile pharmacology lab, aka the Cannavan, at CU ��ý��.

This, and other research efforts across campus have contributed dozens of scientific studies to the field at a time when all but 10 states allow use of cannabis for medical purposes and half permit recreational use.

“As one of the first groups in the country to study real-world cannabis use with rigorous, ecologically valid methods, we’ve had the opportunity to lead work that helps bridge science and lived experience-so individuals, clinicians, and policymakers can make more informed, evidence-based decisions,” said associate professor Cinnamon Bidwell, who co-leads CUChange with Psychology Professor Angela Bryan.

Here’s a snapshot at what CU research has revealed so far, and what scientists are working to learn.

Don’t always trust the labels

Nearly half of cannabis flower products are inaccurately labeled when it comes to potency, with most showing they contain more THC than they really do, according to a study published in the journal Scientific Reports. Meanwhile, labels on cannabis concentrates like oils and waxes tend to be accurate, with 96% shown to match what’s inside. Read more.

Weed can make workouts more fun but it does not enhance performance

A study of 42 runners, published in the journal Sports Medicine, shows THC and CBD products can increase positive mood and enjoyment during exercise, but THC can also increase heart rate and make exercise feel more effortful. Read more.

CBD can ease anxiety without the risks that can come with THC

The study of 300 people, published in the journal Cannabis and Cannabinoid Research, was the first randomized trial to examine how legal, commercially available cannabis impacts anxiety symptoms.

The study comes as one in five U.S. adults suffer from an anxiety disorder and prescriptions for anti-anxiety medications are on the rise. Read more.

Cannabis may ease ‘chemo brain’ and improve sleep among cancer patients

The study, published in the journal Exploration in Medicine, is among the first to assess how cannabis bought over the counter at dispensaries—rather than government-supplied or synthetic varieties—impacts cancer symptoms or chemotherapy side effects. It also sheds light on the wide variety of products cancer patients use now that marijuana is legal in most states. Read more.

Can taking CBD help people use less weed? A new study explores

An ongoing CU ��ý�� study is exploring whether taking cannabidiol (CBD), a non-intoxicating ingredient in the Cannabis sativa plant, can help people with an unhealthy dependency smoke less weed or give it up entirely. Read more and watch a video.

A THC breathalyzer? It’s in the works

Fourteen years after Colorado and Washington became the first U.S. states to legalize recreational cannabis, police still lack a reliable method for detecting whether someone smoked a joint or ate a gummy recently and whether they are too impaired to drive.

Researchers at CU ��ý�� hope to help solve that problem, using a laboratory on wheels and state-of-the-art chemistry to map the peaks and declines of a cannabis high in real time. Read more.

Since 2017, researchers at the Center for Health & Neuroscience, Genes & Environment (CUChange) have been using a mobile van, a.k.a. the Cannavan, to study the real-time impacts of cannabis. In recognition of Cannabis Awareness Month, here's a look at what they've learned.

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Mental, physical illnesses often go hand in hand. Genetic study helps explain why

Lisa Marshall — Wed, 08 Apr 2026 16:22:46 +0000

Mental, physical illnesses often go hand in hand. Genetic study helps explain why Lisa Marshall Wed, 04/08/2026 - 10:22

Lisa Marshall

For centuries, mental illness and physical disease have been viewed as two distinct categories, each with its own field of study, its own doctors, and its own menu of treatments.

New CU ��ý�� research calls that age-old dichotomy into question, showing that the same chunks of DNA that underly psychiatric disorders like depression, PTSD and ADHD are associated with risk of a host of physical ailments, too.

The study of nearly two million people, published in the journal Nature Communications, sheds light on just how often, and why, psychiatric and physical diseases go hand in hand. It could ultimately pave the way for new therapies that address both, the authors said.

Andrew Grotzinger

“The surprising finding here is not that psychiatric disorders and medical disorders are linked, but rather, how much they are linked,” said senior author Andrew Grotzinger, assistant professor of psychology and neuroscience. “At the genetic level, we found that there is so much overlap they are really not two different classes of diseases at all.”

Diseases come in pairs

Grotzinger’s previous research has shown that people with one psychiatric disorder often have many (41% meet the criteria of four or more), likely due to shared genetic factors. Physical disorders also come in groups, with 38% of the global population having two or more chronic conditions.

Only recently have scientists begun to explore how often physical and psychiatric disorders coincide. One recent study, looking at medical records of Danish citizens, found that having a mental health disorder boosted risk of a physical disease by 37%, with some psychiatric disorders increasing risk of some physical disorders by nearly 400%. People with depression, studies show, are 1.5 times as likely as those without depression to develop heart disease.

“In the clinic, you rarely see someone with just one condition walk into a room,” said first author Jeremy Lawrence, a doctoral candidate in clinical psychology. “If we can better understand the cross-talk between these conditions, we can do a better job helping the whole patient.”

To determine just how common these physical-mental combinations are, Grotzinger and Lawrence analyzed genetic material and health information from 1.9 million people.

They looked at which chunks of DNA are associated with 73 physical outcomes across eight medical domains (neurological, respiratory, circulatory, digestive, endocrine/metabolic, genitourinary, musculoskeletal, and cancer). Then they did the same with 13 psychiatric disorders across five categories (compulsive, psychotic/thought, neurodevelopmental, internalizing, and substance abuse).

When comparing physical and mental disorders, the genetic risk factors overlapped 42% of the time.

“We found that, at the genetic level, the shared risk between psychiatric and non-psychiatric medical disease is pervasive and substantial,” said Lawrence.

Neurodevelopmental disorders, like ADHD, were most likely to be associated with physical illnesses. In the case of ADHD, it had more in common, genetically, with physical diseases than with other psychiatric diseases.

Major depression, PTSD and substance use disorders also had high levels of shared risk with physical illnesses. In contrast, compulsive disorders like obsessive compulsive disorder and Tourette syndrome, were seldom associated with physical illnesses and seemed to have a protective effect when it came to digestive disorders.

Some specific diseases tended to go together.

Jeremy Lawrence

For instance, schizophrenia tended to pair with gastrointestinal problems; bipolar disorder tended to pair with genitourinary disorders and sleep problems. Depression and anxiety tended to pair with cardiovascular disease.

The chicken or the egg?

Lawrence noted that having a mental illness, like depression, could lead to behaviors—like eating poorly or leading a sedentary lifestyle—that precipitate poor physical health. In other cases, like a cancer diagnosis, physical illness could boost risk of mental illnesses like depression. In some cases, a common chunk of DNA may independently boost risk of both a physical illness and a mental illness.

Lawrence imagines a day when therapies could be developed that hit both physical and mental health targets at once.

He pointed to GLP-1 agonists—originally developed for diabetes, then prescribed for weight loss, and now showing promise for use in substance abuse disorders—as an example of how drugs meant for physical disease are making their way into the mental health realm.

Genetics could also be used to predict which groupings of diseases across the mental and physical spectrums a person is susceptible to so they can intervene early.

For now, the research shows that addressing mental illness can go a long way in improving overall health, said Grotzinger. It could also help break down the silos between psychology and general medicine.

“You can ask someone to spit in a tube or put a blood pressure cuff on to diagnose physical illness, but in many ways, we don’t have that for psychiatric disorders, so some have viewed them as more esoteric and less tangible,” said Grotzinger. “Psychiatric disorders are just as real as any medical disease. Our findings help make that argument.”

An analysis of DNA from two million people shows that that the same genetic architecture that underlies things like depression, ADHD and substance abuse also boosts risk of a host of physical illnesses.

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A simple shot shows promise to reverse osteoarthritis within weeks

Lisa Marshall — Mon, 06 Apr 2026 14:19:06 +0000

A simple shot shows promise to reverse osteoarthritis within weeks Lisa Marshall Mon, 04/06/2026 - 08:19

Lisa Marshall

A research team including scientists and engineers from CU ��ý��, CU Anschutz and Colorado State University has developed a suite of new therapies that prompt aging or damaged joints to repair themselves within weeks, according to animal studies.

The new osteoarthritis treatments include a single, regenerative injection to a joint and a biomaterial repair kit that recruits the body’s own cells to patch holes in damaged cartilage.

To expedite the research, the federal Advanced Research Projects Agency for Health (ARPA-H) announced this week that the multidisciplinary team will advance to the next phase of the up to $33.5 million project. The project is under the ARPA-H Novel Innovations for Tissue Regeneration in Osteoarthritis (NITRO) program. NITRO is led by ARPA-H Program Manager Dr. Ross Uhrich.

“In two years, we were able to go from a moonshot idea to developing these therapies to demonstrating that they reverse osteoarthritis in animals,” said lead principal investigator Stephanie Bryant, professor of chemical and biological engineering at CU ��ý��.

She is leading the project along with co-principal investigators Karin Payne, associate professor of orthopedics at CU Anschutz, Michael Zuscik, professor of orthopedics at CU Anschutz, and Laurie Goodrich, professor of orthopedics in the Department of Clinical Sciences at CSU.

“Our goal is not just to treat pain and halt progression, but to end this disease,” said Bryant.

Stephanie Bryant works with Laurel Stefani, a biomedical engineering doctoral candidate from Richardson, Texas.

Osteoarthritis is the third most common disease in the U.S., impacting roughly one in six people over age 30 worldwide. It causes cartilage, the buffering tissue that keeps bones from grinding together, to decay. Over time, it can damage bone too, reshaping the joint and making movement excruciating.

Patients are generally limited to two options: Treat the pain or replace the joint. There is no cure. To move toward one, the Colorado team is taking two approaches.

The first centers around repurposing an existing drug already approved by the Food and Drug Administration and applying it to treat osteoarthritis. Bryant, a materials scientist, and her colleagues developed a patented particle delivery system that can be injected into the joint and provide intermittent bursts of the drug for months.

For those with significant lesions in cartilage or bone, the team also developed a cocktail of engineered proteins that can be injected arthroscopically and cured into place, where it recruits the body’s own progenitor cells to patch the gap.

When the team used the injection to treat animals with arthritic joints and injuries, the joints returned to a healthy state within four to eight weeks. When they patched holes in bone or cartilage, they saw “full regeneration and repair of the defect,” said Bryant. In human cells derived from patients undergoing joint replacements, the therapies had a clear regenerative effect.

NITRO was the inaugural program of ARPA-H, created to develop “minimally invasive therapeutics that fully regenerate damaged joints.” Two years ago, NITRO awarded the Colorado team up to $33.5 million, contingent on positive results, to pursue this goal.

With phase one successfully complete, the team is now advancing to phase two.

“It’s super exciting to be a part of the very first program of ARPA-H and to be one of the first teams to advance to the second phase,” said Bryant.

Dr. Evalina Burger, professor and chair of the Department of Orthopedics at CU Anschutz, said she has seen osteoarthritis afflict everyone from grandparents who can’t comb their hair without shoulder pain to runners and hockey players who had to give up the sport they love due to knee or back pain.

“At the moment, the options for many patients are either a massive, expensive surgery or nothing. There’s not a lot in between,” said Burger, who has been following the team’s research with interest. “That’s why ARPA-H is so important.”

She and Bryant imagine a day when those in the earlier stages of the disease could access an affordable single-dose therapy to keep their joints healthy for years. Those with injured tissue could have it fixed in a single doctor’s visit with a quick recovery.

The team hopes to publish their animal findings in a peer reviewed journal later this year and has formed a company, Renovare Therapeutics Inc. to move toward commercialization.

If future studies go according to plan, Bryant anticipates clinical trials could be underway in as soon as 18 months.

“This could be a real game-changer for patients,” said Bryant.

A CU ��ý��-led team has developed a suite of new therapies aimed at reversing osteoarthritis in a single injection. With animal studies showing promise and funding from the Advanced Research Projects Agency for Health extended, the team could be ready for human trials by 2028.

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Can concussions cause fear of movement?

Megan M Rogers — Mon, 23 Mar 2026 17:42:11 +0000

Can concussions cause fear of movement? Megan M Rogers Mon, 03/23/2026 - 11:42

Colorado Arts and Sciences Magazine

CU ��ý�� neuroscience student Alexander Wiegman's research finds that a history of concussions doesn't necessarily lead to later kinesiophobia.

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Python blood could hold the secret to healthy weight loss

Lisa Marshall — Thu, 19 Mar 2026 20:23:30 +0000

Python blood could hold the secret to healthy weight loss Lisa Marshall Thu, 03/19/2026 - 14:23

Lisa Marshall

A ball python. Photos by Patrick Campbell/CU ��ý��

CU ��ý�� researchers have discovered an appetite-suppressing compound in python blood that helps the snakes consume enormous meals and go months without eating yet remain metabolically healthy.

The research, a collaboration with scientists at Stanford Medicine and Baylor universities, could inform new weight loss therapies that promote satiety without the nausea and muscle loss that can come with existing drugs.

Professor Leslie leinwand, left, and PhD candidate Skip Maas look on at Maas's pet pythons during their visit to the lab. In addition to keeping pet pythons, Maas studies python metabolism.

The findings were published in the journal Nature Metabolism on March 19.

“This is a perfect example of nature-inspired biology,” said senior author Leslie Leinwand, a distinguished professor of Molecular, Cellular and Developmental Biology who has been studying pythons in her lab for two decades. “You look at extraordinary animals that can do things that you and I and other mammals can’t do, and you try to harness that for therapeutic interventions.”

Metabolic superheroes

Pythons can grow as big as a telephone pole, swallow an antelope whole, and go months or even years without eating—all while maintaining a healthy heart and plenty of muscle mass. In the hours after they eat, Leinwand’s research has shown, their heart expands 25% and their metabolism speeds up 4,000-fold to help them digest their meal.

To get a better sense of what makes these superpowers possible, Leinwand teamed up with Jonathan Long, an associate professor of pathology at Stanford School of Medicine who studies metabolic byproducts in the blood, or metabolites, to learn how mammals take in and expend energy.

Long’s lab recently examined the blood of another curious creature—the racehorse—for insight on how the animals can endure those all-out sprints.

“If we truly want to understand metabolism, we need to go beyond looking at mice and people and look at the greatest metabolic extremes nature has to offer,” said Long.

For the new study, the team measured blood samples from ball pythons and Burmese pythons, fed once every 28 days, immediately after they ate a meal.

In all, they found 208 metabolites that increased significantly after the pythons ate. One molecule, called para-tyramine-O-sulfate (pTOS) soared 1,000-fold.

Further studies, done with Baylor University researchers, showed that when they gave high doses of pTOS to obese or lean mice, it acted on the hypothalamus, the appetite center of the brain, prompting weight loss without causing gastrointestinal problems, muscle loss or declines in energy.

The study found that pTOS, which is produced by the snake’s gut bacteria, is not present in mice naturally. It is present in human urine at low levels and does increase somewhat after a meal.

But because most research is done in mice or rats, pTOS has been overlooked.

“We’ve basically discovered an appetite suppressant that works in mice without some of the side-effects that GLP-1 drugs have,” said Leinwand, referring to drugs like Ozempic and Wegovy, which act on the hormone glucagon-like petide-1 (GLP-1).

Nature-inspired weight loss therapies

Leinwand noted that these new drugs were inspired by another reptile, the Gila monster. Gila monster venom contains a hormone similar to human GLP-1.

Those drugs are now used by millions, but studies show that as as many as half of people who use them stop taking them within a year.

“We believe there is still room for therapeutic growth in this market,” said Leinwand.

She, Long and her CU ��ý�� colleagues have formed a start-up, Arkana Therapeutics, to work toward commercializing some of the lessons they are learning from pythons.

They imagine a day when chemically synthesized analogs of the rare metabolites found in pythons could be turned into therapies to help people.

Ball pythons. Credit: Patrick Campbell/CU ��ý��

Weight loss isn’t the only therapeutic goal they are eyeing.

Age-related muscle loss, or sarcopenia, impacts nearly everyone to some degree as they get older, and people who have health problems that make it hard for them to exercise are hit particularly hard. To date, there are no therapies to halt or reverse sarcopenia.

The snakes may offer insight into how to do that, too, Leinwand said.

In future research, the team hopes to explore how pTOS works in people and catalogue the function of the other metabolites that increase after pythons eat. Some metabolites the researchers identified in their study soar by 500% to 800%.

“We’re not stopping with just this one metabolite,” said Leinwand. “There’s a lot more to be learned.”

Scientists have discovered a novel metabolite in pythons that quells appetite without causing gastrointestinal side effects or muscle wasting. The findings could lead to new weight loss therapies with fewer side effects.

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