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Women who go through menopause later in life have healthier blood vessels for years to come than those who go through it earlier, according to new CU Boulder research.

The study, published in the American Heart Association journal , offers new insight into why females who stop menstruating later are significantly less likely to have heart attacks and strokes in their postmenopausal years.

Arriving just in time for Women’s Heart Health month, the findings could help lead to new therapies, including dietary interventions, to reduce risk of heart disease which is the No. 1 killer of women.

“Our paper identifies that there’s actually a physiological benefit to later-onset menopause and is one of the first to identify the specific mechanisms driving these benefits,” said first author Sanna Darvish, a PhD candidate in the Department of Integrative Physiology.

Nearly half of women in the U.S. live with heart disease and it accounts for about female deaths each year. While females are less likely to die of a heart attack or stroke than males for most of their life, their risk spikes and overtakes male risk after menopause.

But there is one notable caveat to this trend.

Previous studies show that women who hit menopause—defined as going one year without a period—at age 55 or later are as much as 20% less likely to develop heart disease than those who cease menstruation at the usual 45 to 54 years old.

Darvish and her colleagues at CU’s Integrative Physiology of Aging Laboratory set out to determine why.

They assessed the vascular health of 92 women, looking specifically at a measure called brachial artery flow-mediated dilation (FMD), or how well their brachial artery—the main blood vessel in the upper arm—dilates with increased blood flow.

The team also measured the health of the women’s mitochondria, the energy powerhouses in the cells lining their blood vessels. And they took a close look at what molecules were coursing through their bloodstream.

Not surprisingly, all the postmenopausal women had significantly worse arterial function than their premenopausal counterparts. That’s in part because, as people age, they produce less nitric oxide, a compound that helps blood vessels dilate and keeps them from getting stiff and developing plaque. Mitochondria in cells lining the blood vessels also become dysfunctional with age and generate more damaging molecules called free radicals, explained Darvish.

A spike in risk

When menopause hits, the age-related decline in vascular health accelerates. But the 10% or so of women who experience late-onset menopause appear to be somewhat protected from this effect, said senior author Matthew Rossman.

For instance, the study found that vascular function was only 24% worse in the late-onset menopause group compared to the premenopausal group, while those in the normal-onset group had 51% worse vascular health.

Remarkably, such differences between the groups persisted five years or more after the women went through menopause, with the late-onset group still having 44% better vascular function than the normal onset group.

In the late-onset group mitochondria lso functioned better, producing fewer free radicals, the study found. The circulating blood of the two groups also looked different, with the late-onset group showing “more favorable” levels of 15 different lipid, or fat, -related metabolites in their blood.

“Our data suggest that women who complete menopause at a later age have a kind of natural inherent protection from vascular dysfunction that can come from oxidative stress over time,” said Rossman, an assistant research professor in the Department of Integrative Physiology.

More research is necessary to determine exactly what drives that protection, but the researchers suspect better mitochondrial function and certain lipids circulating in their blood may play a role.

Next, the team plans to explore how early-onset menopause might impact heart health, and whether nutritional supplements aimed at neutralizing free radicals inside blood vessels might reduce heart disease risk in women at greater risk.

In one previous study, Rossman found initial evidence that MitoQ—a chemically altered version of the antioxidant Coenzyme Q10 that targets mitochondria—reversed blood vessel aging significantly within weeks in male and female subjects. A larger clinical trial is now underway.

“We hope this work puts age at menopause on the map as a female-specific risk factor that women and their doctors discuss more,” said Darvish.

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People who get their news from an ideologically diverse array of sources are more likely to get vaccinated, regardless of their political affiliation, .

“This study shows that being exposed to a range of perspectives encourages critical thinking and makes people less likely to get stuck in a bubble or misled by misinformation,” said senior author Leaf Van Boven, a professor in the Department of Psychology and Neuroscience.

Published in the journal Scientific Reports, the study is among the first to take a close look at how media consumption habits shape vaccine hesitancy, which the World Health Organization has named as one of the “top 10” global threats to public health. The study comes as nationwide, and remains lower than it was before the pandemic. President Donald Trump has also nominated outspoken vaccine skeptic Robert F. Kennedy Jr. to lead the Department of Health and Human Services.

The researchers offer some advice for public health communicators wanting to boost trust and improve vaccine adherence: Encourage people to get out of their echo chambers.

“We as a society have kind of fallen into this belief that you can’t change other people’s minds, but this paper goes to show that when people are introduced to new ideas and evidence, they can make more informed choices and they are willing to change their beliefs,” said Dani Grant, first author of the study and a doctoral candidate at CU Boulder.

Media diet

As part of a larger project exploring public sentiments about COVID-19, Van Boven and Grant surveyed nearly 1,700 people in the spring of 2022, when vaccines and boosters were readily available to the public. The researchers asked respondents their age, ethnicity, education and political affiliation—factors that have previously been shown to shape vaccine adherence—and also asked them to rank how much they got their news from 20 different news outlets.

Outlets ranged from Breitbart News Network and Fox News on the conservative side to MSNBC and Democracy Now on the liberal side. The researchers determined a publication’s ideological tilt using bias ratings from All Sides and Ad Fontes Media, independent media intelligence organizations.

The team gave each respondent a media diversity score based on their answers.

At the time, 21% of those surveyed were not vaccinated, 17% were vaccinated, and 62% were vaccinated and boosted.

The study found that people who reported consuming more conservative media were significantly less likely to be vaccinated and boosted. The researchers noted that, for example, Fox News pundit Sean Hannity told viewers at the time that COVID-19 was made up by the “deep state,” and then-Fox business anchor Trish Regan characterized the virus as “a scam.”

Echo chambers

The most interesting finding, Grant and Van Boven said, was that when people consumed a diverse media diet, even if it included a range of conservative outlets, they still tended to get vaccinated.

“People who consumed news and opinions from a variety of political perspectives were more likely to be vaccinated, even after accounting for their political affiliation, age, gender, race and education,” said Van Boven.

When it came to trust in science, media consumption also had a notable influence. Those who consumed only left-leaning media had very high trust in science, while those who consumed only right-leaning media were highly skeptical.

The authors said that understanding the factors associated with vaccine hesitancy is critical not only for addressing the ongoing threat of COVID-19 but also for tackling other diseases like influenza, measles and whooping cough. Vaccination rates for all three diseases are declining in the United States.

“When people delay or refuse vaccines, we see avoidable deaths, illness and economic losses,” said Van Boven. “Vaccines are among our most effective public health tools, but their power depends on public trust.”

To regain trust, scientists and public health officials might also do well to step out of their own echo chambers, Grant said, sharing their perspectives and research with outlets they may not typically engage with.

“This is an opportunity for scientists to reflect on where we are not being as constructive as we could be,” she said. “I think that we should all be interacting across the media spectrum.” 

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If you feel stuck in your job, you’re not alone. New research sheds light on how feelings of defeat and entrapment in the workplace can not only heighten the desire to quit but can also trigger impulsive decisions to leave.

“We often assume that quitting a job is a rational decision motivated by a better opportunity,” said David Hekman, associate professor of leadership and information analytics and co-author of the study. “But our research shows that, for many, it’s not about finding something better. It’s about escaping a situation that feels unbearable—and that’s often an emotional decision, not a rational one.”

The study, published in July 2024 in the  and co-authored by Ryan Ragaglia, a doctoral student in organizational behavior at the Leeds School of Business, examines "perceived entrapment"—a form of negative attachment where employees feel so bound to their jobs that they see no way out.

“Traditionally, attachment was seen as a positive thing. The more attached an employee is to their job, the more likely they are to stay,” Ragaglia said. “What we found is the opposite … There's a point where you can feel so attached to your job, so stuck, that you actually start thinking about quitting.”

Feelings of entrapment may stem from a variety of factors, such as lack of career advancement opportunities, overwhelming workloads or simply feeling undervalued. But according to the study, the impact of these emotions is more profound than previously thought—it can push employees to make drastic decisions that may seem like self-sabotage.

Parallels to suicide research

To understand why employees might impulsively quit their jobs, the researchers drew insights from suicide research. Ragaglia notes that just like a person contemplating suicide may make an emotional, irrational decision despite no guaranteed better outcome, employees feeling trapped by their jobs may also quit in a desperate bid for control. The decision is often rooted in emotional distress rather than a clear-headed, logical evaluation of the future.

If you or someone you know is struggling or in crisis, call or text 988 or chat . Learn about suicide prevention resources at CU Boulder.

"The idea was based on my own experiences with suicidal ideation,” Ragaglia said. It also sprung to mind during Hekman’s organizational behavior seminar. “We were discussing withdrawal and how employees tend to pull back when considering quitting, and I thought to myself, ‘This sounds a lot like what I was doing when I was contemplating suicide.’”

“That set off a chain of thoughts in which I imagined suicide as a potential metaphor for turnover. We looked into the suicide literature, and that’s where we found the constructs of defeat and entrapment, which seemed very applicable to turnover,” he said.

A vicious cycle

Employees who impulsively quit often find themselves in a worse situation, forcing them to take the first available job that comes along—a job that often doesn’t align with their values or career goals. This leads to more feelings of entrapment, creating a “vicious cycle” of dissatisfaction and repetitive quitting, Hekman said.

The decision to quit can also lead to further emotional and financial instability, and again, makes them feel more trapped, he added.

The researchers are currently interviewing “chronic quitters” and studying common triggers and scenarios that lead to feelings of entrapment. So far, their findings point to a few causes.

“We’ve found that boredom, lack of career advancement opportunities and financial pressures are the primary triggers for feelings of entrapment,” Ragaglia said. “While this is still preliminary, we’re continuing to explore these factors in more depth.”

How employers can help

The research has critical implications for anyone feeling overwhelmed or stuck at work. While Ragaglia and Hekman are still studying solutions for employees, they have recommendations to help organizations reduce feelings of entrapment among employees.

“Employers and supervisors should focus on helping their employees feel like they are ‘winning,’” Ragaglia said. “This can be as simple as recognizing successes and setting achievable goals. We also suspect that employees will feel less trapped if there are opportunities for career advancement and if employers provide flexible work arrangements.”

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This time of year, millions of people turn to diets, exercise and medication to help them get their weight in check.

New CU Boulder research suggests another surprising tool could help them achieve their resolution: Exposure to beneficial bacteria.

The study, , shows that animals injected weekly with a microorganism found in cow’s milk and soil were essentially immune to weight gain from a high-fat, high-sugar diet.

“What is so striking about this study is that we saw a complete prevention of diet-related weight gain in these animals,” said senior author Christopher Lowry, professor of integrative physiology. “This suggests that exposure to beneficial bacteria can protect us against some of the negative health outcomes of the typical Western diet.”

How ‘old friends’ keep us healthy

The study is the latest to report the benefits of healthy forms of bacteria known as “old friends” that evolved alongside humans but that we have lost touch with as we’ve moved from farms to more sterile, urban environments.

“As we have lost contact with these old friends that served to regulate our immune system and suppress inappropriate inflammation it has put us at higher risk for inflammatory diseases,” said Lowry.

, Lowry found that inoculation with an organism called Mycobacterium vaccae (M. vaccae), present in cow’s milk and soil, can prevent stress-induced inflammation and associated health problems in mice.

Those and subsequent findings have prompted Lowry to explore the idea of developing a “stress vaccine” derived from dirt-dwelling microbes.

For the new study, he and first author Luke Desmond, a PhD candidate in his lab, set out to determine whether M. vaccae could also help counter some of the brain inflammation and resulting anxiety that can come with a poor diet.

Beyond the Story

Our bioscience impact by the numbers:

• Top 7% university for National Science Foundation research funding
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• 89-plus biotech startups with roots at CU Boulder in past 20 years

They did not set out to do a weight loss study.

One set of adolescent mice was fed standard, healthy chow for 10 weeks. The other consumed the rodent equivalent of Big Macs and fries, with 40% fat, 40% carbohydrates (half of them from sugar) and 20% protein.

Half of each group also got weekly injections of M. vaccae.

All groups ate about the same number of calories, and all the mice gained some weight as they matured into adulthood.

As expected, the untreated junk food group began to gain significantly more weight at about six weeks than the healthy eaters. By study’s end, they weighed about 16% more than the healthy eaters and had significantly more visceral fat — the “bad fat” that collects around organs and can boost risk of heart disease and diabetes.

To Lowry and Desmond’s surprise, there was no difference in weight gain between the junk food group that got injections of good bacteria and the healthy eaters. The inoculated mice also had less “bad fat” at the study’s end.

“This finding suggests that M. vaccae effectively prevents the excessive weight gain induced by a Western-style diet,” said Desmond.

A dirt vaccine

More research is needed to determine just how exposure to a bacteria found in dirt could prevent weight gain, and whether it can do so in people.

But Lowry has some ideas.

He suspects M. vaccae may act directly on immune cells to tamp down inflammation, make fat healthier and boost metabolism.

He hopes to do more studies to determine whether M. vaccae taken orally has the same impact, and whether it could help someone who is already overweight lose weight.

With assistance from Venture Partners at CU Boulder, the university’s commercialization arm, he and his colleagues have launched a startup called Kioga to pursue new microbe-based ingredients for preventing weight gain and promoting health.

For now, Lowry says the best way to get exposed to helpful ‘old friends’ is to get out in nature, work in the garden and eat a variety of fresh vegetables (they soak up healthy microbes from soil).

Why not just ditch junk food? 

That’s easier said than done.

“More than half of the food sold in grocery is junk food. It’s everywhere and it’s hard to avoid,” Lowry said. “If we can simply restore our exposure to these old friends, we could potentially prevent weight gain and other health impacts even in the presence of our terrible Western diet.”

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Six months after the Marshall Fire destroyed more than 1,000 houses in Boulder County, Colorado, more than half of residents of surviving homes in the area reported physical symptoms—including headaches, sore throats or a strange taste in their mouth—that they attributed to poor air quality, has found.

A companion study showed that the air quality inside one home post-fire equaled that of downtown Los Angeles in the 1990s on a high pollution day, with hazardous gases lingering for weeks.

“Our research suggests that there could be important health impacts for people returning to smoke- or ash-damaged homes after a fire and that we need to have systems in place to protect them,” said Colleen Reid, associate professor of geography and co-author of the studies.

The papers, published this week in ACS Environmental Science & Technology Air, are the first to explore air quality inside smoke- and ash-damaged homes and to assess the health impacts on people who live in them. They come as fires in the Wildland-Urban Interface, like in Paradise, California, in 2018 and Lahaina, Hawaii, in 2023 grow more common.

“A lot of time has been spent studying wildfire smoke—what you get when you burn vegetation. But what do you get when you burn a home, with all its furniture and electronics and cars? Until now, there has been very little known,” said co-author Joost de Gouw, a professor of chemistry and fellow with the Cooperative Institute for Research in Environmental Sciences (CIRES).

A record winter blaze

Fueled by 100-mile-per-hour winds and record dry conditions, the Dec. 30, 2021, Marshall Fire burned 1,084 buildings in densely populated areas, took two lives and forced 37,000 people to evacuate.

Once residents returned home, scientists at CU Boulder, just 4 miles from the fire’s ignition, started getting calls.

“At first, they felt really lucky, but when they went into their homes they saw ash everywhere and it smelled differently—like a campfire or chemicals,” said Reid. “They asked: What should we do? We don’t know if it’s safe to go back in.”

With little research offering answers, the scientists began to investigate.

Ten days after the fire, de Gouw’s team erected field instruments in an intact home bordering a block where houses burned down. Over five weeks, they continually the presence of 50 gases. ( about the study here.)

Meanwhile, Reid and colleagues developed a survey to send to residents within the burn perimeter, as well as a random sample of those within 2 miles.

At six months, 642 people had responded; 413 had responded at the one-year mark.

Some 55% of respondents reported symptoms that they attributed to the fire at the six-month mark, and survey answers depended largely on the condition of their home when they returned home.

For instance, those who found ash inside were three times as likely to report headaches compared to those who didn’t find ash; those who reported an odd odor were four times as likely to report headaches compared to those who did not pick up an unusual scent.

People with the same symptoms tended to cluster together, according to computer mapping analyses. For example, those living near destroyed homes, especially in the direction the wind was blowing the day of the fire, were far more likely to report a strange taste in their mouth.

“These findings are consistent with chemical exposures and suggest that residents of smoke- and ash-damaged homes may have experienced lingering air quality and physical health challenges months after the fire,” said Reid.

Long-term impacts uncertain

The authors cannot say which chemicals caused the health impacts that survey respondents reported. But measurements in one home found high levels of volatile organic compounds (VOCs) like benzene, a carcinogen found in gasoline and diesel exhaust.

Dust samples also showed high levels of copper, zinc, arsenic and industrial pollutants called polycyclic aromatic hydrocarbons (PAHs), which are known to cause eye irritation.

“If your home survives, and the neighbor two doors down burns, all those melted things can get into the air and find their way into your home” settling into furnishings, carpets and drywall, said Reid.

The authors stress that VOCs are only considered carcinogenic at levels much higher than what they found, and people are regularly exposed to low levels daily through pollution.

Their research found that simple measures, like opening windows and using low-cost, carbon-activated air filters, can substantially improve air quality.

One year after the fire, the number of residents reporting symptoms had declined to just 33% and most said confidence in their home’s air quality had improved.

Until more studies are done, the researchers cannot say whether such exposures can lead to long-term health problems.

Nonetheless, Reid urges anyone going inside a smoke- or ash-damaged home just after a wildland urban interface (WUI) fire to use caution, wearing KN95 masks and gloves.

They hope their ongoing research can lead to clearer guidelines for policymakers and insurance companies about when it is safe for people to return to smoke-damaged homes.

“This wasn’t just any fire. It felt personal,” said de Gouw. “Knowing that we could at least begin to provide some answers to our community has made the work extra meaningful.” 

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Law enforcement will be out in force this holiday season, with on the lookout for impaired drivers.

Yet 12 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 Boulder and the National Institutes of Standards and Technology (NIST) 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.

Their new study of 45 regular cannabis users could help lead to standardized protocols for measuring impairment at the roadside and inform development of a new generation of cannabis breathalyzers.

“The ultimate goal is to develop a reliable tool that supports fair law enforcement and helps keep our roads safe,” said Cinnamon Bidwell, associate professor of psychology and neuroscience and co-director of CUChange, a lab that studies health risks and benefits of cannabis.

Needle in a haystack

Since the 1950s, police have measured ethanol in breath as an indicator of alcohol impairment.  With cannabis, it’s more complicated.

Unlike ethanol, which is exhaled in copious amounts in a gaseous vapor, the main psychoactive ingredient in cannabis (tetrahydrocannabinol or

 THC) is exhaled in trace amounts via tiny aerosol particles.

After consuming alcohol, a person exhales 1 million times more ethanol with a single breath than they would in 12 breaths after consuming cannabis, according to one NIST study.

“With THC, it’s like looking for a needle in a haystack,” said Tara Lovestead, a NIST chemical engineer who spearheaded that study.

THC also lingers in tissues, making it hard to discern with blood or breath whether someone used an hour ago or last week.

With alcohol, there is a clearly established BAC (blood alcohol concentration) above which someone is considered impaired (.08% in most states). Because there is no clear correlation between more THC in blood and breath and greater intoxication, there is no BAC equivalent for cannabis testing—yet.

Several cannabis breathalyzers exist on the market, some being tested by law enforcement. But it’s unclear whether they can be trusted, said Bidwell.

“Scientifically, we just aren’t there yet,” she said. “There are too many questions that need to be answered first in an unbiased setting. That’s what we’re trying to do.”

A two-breath test?

In a previous pilot study, the team concluded that while it’s possible to detect trace levels of cannabis in breath, a single breath measurement cannot reliably indicate when cannabis was used or whether that person is impaired.

That could leave the door open for someone to be wrongfully accused of driving under the influence.

“It’s a huge problem and a matter of social justice,” Bidwell said.

But what if you took multiple breath samples?

To test that approach, the research team will recruit regular cannabis users between age 25 and 50. Half will use a THC-based flower strain; the other half will use a THC-based concentrate. To ensure that participants use the same product, all will get their cannabis from the same dispensary, Native Roots Dispensary in Boulder, which has worked with CU Boulder on several research projects.

Because cannabis is federally illegal, researchers are not allowed to handle or administer it. So, Bidwell’s team uses a mobile pharmacology laboratory—a white Sprinter van equipped with specialized equipment—to bring the lab to the people.

“The van enables us to measure in real time the impact of legal market forms of cannabis that people actually use,” she said.

After undergoing a baseline test in the van, participants go inside their residence and use as much cannabis as they wish. Then they return to the van for 13 breath tests over two hours and a series of tests to gauge how high they feel.

Lovestead and chemical engineer Kavita Jeerage, who leads the NIST team, will analyze the more than 1,200 unique samples to provide a clearer picture of what a baseline level of cannabis looks like in the breath of a regular user and how that number rises and falls as their level of intoxication changes.

While they don’t intend to develop their own cannabis breathalyzer, the research could be used to help others accurately interpret breath samples.

A BAC for THC

in blood suggests that levels of THC peak within about 15 minutes of use, before dropping precipitously for the next three hours.

In theory, if a driver were to take two breathalyzer tests 10 to 20 minutes apart after using cannabis, their second reading would be lower. If they hadn’t used recently, the two numbers would be the same.

The new study will determine whether that theory could be put into practice with a multi-breath test to determine recent use.

Subsequent studies could also help establish a BAC for THC, that could determine if someone is safe to drive when combined with other field tests.

The new test could be useful not only for police, but also for cannabis users themselves.

“Most people who use cannabis, whether for recreational or medical reasons, want to do so responsibly,” Bidwell said. “If there is a tool they can use to assure they aren’t putting anyone at risk, that would be hugely beneficial.” 

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