Research shows that greater subjective well-being can lead to enhanced immune function and a lower incidence of chronic disease. But when does happiness start to exert its positive influence, and is there a point when this effect caps out? Researchers looked at national level data from 123 countries and found there is: on a scale from zero to 10, people started gaining health benefits once they surpassed a threshold that lies at around 2.7. Once above, each 1% of additional happiness could lead to a small decrease in mortality risk from non-communicable diseases.
Heart disease, cancer, asthma, and diabetes: All are chronic or non-communicable diseases (NCD), which accounted for about 75% of non-pandemic related deaths in 2021. They may result from genetic, environmental, and behavioural factors, or a combination thereof. But can other factors also influence disease risk?
Now, a new Frontiers in Medicine study has investigated the relationship between happiness and health to find out if happier always means healthier and to determine if happiness and co-occurring health benefits are linear or follow a specific pattern.
“We show that subjective well-being, or happiness, appears to function as a population health asset only once a minimum threshold of approximately 2.7 on the Life Ladder scale is surpassed,” said first author Prof Iulia Iuga, a researcher at 1 Decembrie 1918 University of Alba Iulia. “Above this tipping point, increased happiness is associated with a decrease in NCD mortality.”
Happy equals healthy
“The life ladder can be imaged as a simple zero to 10 happiness ruler, where zero means the worst possible life and 10 means the best possible life,” explained Iuga. “People imagine where they currently stand on that ladder.” The team used data sourced from different health organisations, global development statistics, and public opinion polls. The data came from 123 countries and was collected between 2006 and 2021.
A score of 2.7 can be found towards the lower end of the ladder, and people or countries finding themselves there are generally considered unhappy or struggling. “An adjective that fits this level could be ‘barely coping’,” said Iuga. Nevertheless, already at this point, improvements in happiness begin to translate into measurable health benefits.
Once the threshold is surpassed and a country’s collective happiness rises above it, the study found that each 1% increase in subjective well-being is linked to an estimated 0.43% decrease in that country’s 30-to-70-year NCD mortality rate. This rate refers to the percentage of deaths due to NCDs among individuals aged between 30 and 70.
“Within the observed range, we found no evidence of adverse effects from ‘excessive’ happiness,” Iuga added. Below the 2.7-point threshold, small improvements in happiness (for example, from a score of 2 to 2.2) do not translate to measurable reduction in NCD deaths, the data indicated. Before measurable changes can be unlocked, very low well-being needs to be remedied, the study suggested.
Countries that exceeded this threshold tend to have higher per person health spending, stronger social safety nets, and more stable governance as opposed to the countries falling below it. The average life ladder score across the examined countries during the study period was 5.45, with a minimum of 2.18 and a maximum of 7.97.
There are several ways that governments could raise countries above a score of 2.7, for example through promoting healthy living by expanding obesity prevention and tightening alcohol availability; improving the environment through stricter air-quality standard; and increasing their per capita health spending. The authors said their insights could help guide health and social policies and might aid to integrate well-being into nations’ agendas.
The authors pointed out that the life ladder scores making up their data were self-reported, which may have resulted in measurement errors, differences in cross-cultural response styles, or reporting bias. It is also possible that subnational differences between populations were captured inadequately. In the future, studies should include more measures, such as years lived with disability or hospital admission records, include subnational micro-data, and expand coverage to low-income or conflict states, which may have been overlooked in the data they used, the team pointed out.
Nevertheless, identifying the protective effects of happiness could be an important step towards healthier people. “Identifying this tipping point could provide more accurate evidence for health policy,” concluded Iuga. “Happiness is not just a personal feeling but also a measurable public health resource.”
Changing the amount of sweetness in a person’s diet has no impact on their liking for sweet foods, the results of a new trial suggest. The results also showed no difference in indicators of cardiovascular disease or diabetes risk between people who increased or decreased their intake of sweet-tasting foods over a six-month period.
The research team suggest that consequently public health organisations may need to change their current advice on reducing sweet food consumption to tackle the obesity crisis.
The study, published in the American Journal of Clinical Nutrition, was carried out by Wageningen University and Research in the Netherlands and Bournemouth University in the UK.
“People have a natural love of sweet taste which has led many organisations, including the World Health Organisation, to offer dietary advice on reducing the amount of sweetness in our diets altogether,” said Katherine Appleton, Professor in Psychology at Bournemouth University and corresponding author for the study. “However, our results do not support this advice, which does not consider whether the sweet taste comes from sugar, low calorie sweeteners, or natural sources.” she added.
During the trial, 180 participants were split into three groups. One group consumed a diet containing a high amount of sweet-tasting food, a second group consumed a low amount and a third consumed an average amount. The sweetness in the foods provided for their diets came from a combination of sugar, natural sweetness or low-calorie sweeteners.
After one, three and six months, participants were surveyed on whether their liking and perception of sweet foods had changed. They were also weighed and provided blood and urine samples to measure any changes in their diabetes risk and cardiovascular health.
At the end of the trial, the researchers found no significant differences in any of the measures across the three groups. Participants also reported a spontaneous return to their previous intake of sweet foods after the six months.
Based on their results, the study team are recommending that public health organisations may need to change their current advice on reducing sweet foods to tackle overweight and obesity.
“It’s not about eating less sweet food to reduce obesity levels,” Professor Appleton said. “The health concerns relate to sugar consumption. Some fast-food items may not taste sweet but can contain high levels of sugar. Similarly, many naturally sweet products such as fresh fruit and dairy products can have health benefits. Public advice therefore needs to concentrate on how people can reduce the amount of sugar and energy-dense foods they consume,” she concluded.
Getting to grips with rising diabetes rates is arguably one of the most urgent tasks for South Africa’s public healthcare system, but the setbacks keep coming. While some communities are facing shortages of blood sugar meters and insulin pens, a smaller wave of insulin vial shortages is now on the horizon.
In August, activist Eksoda Mazibuko was sure that years of community organising had finally yielded tangible results for people with diabetes in Hluvukani, a town in Mpumalanga.
The 35-year-old had just received R50 000 from Good Morning Angels, Jacaranda FM’s community upliftment project. It was more than enough for him to buy blood sugar meters and test strips for the fifty-person support group he runs at Tintswalo Hospital in Acornhoek, where stock had run out.
When the body can’t make or use insulin – the hormone that keeps blood sugar in check – people have to watch their levels, so they know how to eat and medicate themselves. It’s a process held together by medicines and an ecosystem of tools such as meters, strips, pens, lancets, needles, syringes, which unravels when one part is missing. Over time, poorly controlled blood sugar causes cumulative damage to one’s body that can result in severe complications such as amputation, blindness, kidney damage, and stroke.
Most people who take pills to treat diabetes need monitoring from time to time, but for the majority of those who are on insulin treatment, it is essential. People with diabetes who are taking insulin must check their blood sugar levels multiple times a day. To do this, they need glucometers – devices that measure the sugar levels in a drop of blood. But access to glucometers is a challenge. Spotlight previously reported that not everyone who needs these home testing devices is given one and those who do receive them rarely get enough test strips and lances to enable proper monitoring of their blood sugar levels.
Without tests and test strips, people in Hluvukani had no way of knowing how to adjust their insulin. Injecting the wrong amount could in extreme cases result in someone going into a coma or dying.
Mazibuko himself, who was diagnosed in 2003 and has always needed insulin, knows how terrifying it can be when monitoring tools are out of reach.
When the devices and test strips finally arrived, he shared a celebratory photo on social media. Excited messages streamed in on WhatsApp, but among them was an upsetting note from a government pharmacist: “You should have asked me before you ordered.”
Unbeknownst to the hospital staff that helped Mazibuko choose the device, the national government’s supplier would be changing, as it does every three years or so when a new tender is awarded. That means state pharmacies would soon stock a different kind of test strip.
Glucometers generally can’t interpret test strips from a different brand or model, so the glucometers that he’d already started to hand out would soon be useless.
“They were already open so I couldn’t send them back. After I worked so hard to get those machines for my community members,” said Mazibuko. “It was heartbreaking.”
According to a report from the Clinton Health Access Initiative, in poorer countries companies make most of their profit on the test strips rather than the glucometers used to read the strips. Spotlight understands that some companies go as far as giving away the devices to lock people into using their specific test strips. According to Cathy Haldane, who leads the non-communicable diseases team at FIND (a global diagnostics alliance), there have been some efforts toward encouraging universal interoperability of test strips, but these efforts haven’t gathered much steam.
Why diabetes is still a national guessing game
South Africa is one of the few countries that buys blood glucose meters and test strips en masse, but there are still lots of people who are treated with insulin who don’t have access to them.
One reason for this is that the national health department buys machines and strips for the public sector but it’s up to provinces to manage stock at pharmacies and clinics, explains Haldane.
A lack of good quality diabetes data could be making harder for health department staff to predict how much they’ll need, she says. Unlike the country’s digital HIV & TB tracking system, there’s no centralised database for diabetes and other chronic diseases such as high blood pressure and cancer. As Spotlight previously reported in-depth, there is a serious lack of reliable diabetes data for South Africa. Haldane says, “that’s how people on insulin treatment who should get a machine and monthly test strips end up going without”.
Not having reliable data leaves national planners, doctors and nurses in the dark about how many people need blood sugar monitors, where the system is failing and how the country is faring against targets outlined in the health department’s action plan for chronic diseases, which lapses in 2027. The plan states that by 2027, the health department wants at least 50% of people receiving care for diabetes to have their blood sugar under control. The available data though, all from pockets of academic research, suggests that we are falling far short of this target.
The diabetes data that is available paints a harrowing picture.
According to a StatsSA report on non-communicable diseases, diabetes was the leading underlying cause of death for women and second biggest underlying cause of death for men in 2018. While other reports suggest that diabetes is lower on the list of top killers, it clearly does claim many lives in the country. The International Diabetes Federation estimates that about half of people with diabetes in South Africa haven’t been diagnosed.
If trends continue, 2018 research suggests the treatment, management and complications of type two diabetes could cost the government as much as R35-billion by 2030.
In rural KZN, insulin pen stockouts persist
Meanwhile, more than 700 kilometers from Hluvukani, in KwaZulu-Natal’s rural King Cetshwayo district, some healthcare staff are using their own money to help keep diabetes services going.
Indira Govender, a doctor affiliated with the Rural Doctors Association of South Africa (Rudasa) who works in the area, says clinic managers are often the ones buying new batteries for blood sugar meters used in the facility and by patients.
The devices use the coin-like batteries also used in some watches, which aren’t easy to find in far flung areas.
Govender worries about the patients on insulin who still have to use a glass vial and syringe to inject themselves. “Not everybody has a fridge to store the insulin in. People struggle to draw up the right amount of insulin, sometimes because they can’t see well,” says Govender.
South Africa ran out of pens in 2024 when the health department’s longtime supplier, Novo Nordisk, stopped manufacturing pens prefilled with the cheapest form of insulin. The news came as global demand surged for one of Novo Nordisk’s long-acting diabetes medicines, semaglutide, because it was shown to also be effective for weight loss. Semaglutide is also provided in pens rather than vials.
In a 2024 letter to Novo Nordisk’s chief executive officer, MSF demanded that the pharma giant either ensure continued supply of the cheapest insulin pens in South Africa or that it offer a newer kind of pen at $1 each. That’s the amount that MSF’s research found would cover production costs, a fair profit margin and an allowance for tax.
The newer pens are filled with a form of insulin that takes effect faster and lasts for longer than previous versions. Novo Nordisk signed a deal in May in which it commits to providing these pens to South Africa until 2027. The department was charged just under $4 (around R75) per pen.
At the government clinic where Govender works in KwaZulu-Natal, however, insulin pens have reportedly not returned to pharmacy shelves.
“We haven’t had pens here since at least 2024,” says Govender.
The KwaZulu-Natal health department did not respond to Spotlight’s queries about the delivery delays.
Local consequences of global disruptions
While some communities are still waiting for insulin pens, a smaller wave of vial shortages is on its way for South Africa, according to an October circular.
Novo Nordisk told the health department to expect six to eight week delays in the delivery of short-acting, medium-acting and longer-acting insulin sold in 10ml vials. The department did not respond to Spotlight’s queries, but the circular listed four alternative prefilled pens that are available and expects stock to stabilise by January 2026.
One of the listed alternatives, Novo Nordisk’s NovoMix30, is also on a list of insulin pens and vials that will be discontinued in 2026, according to a directive issued by the health ministry in New Zealand.
No such directive has been issued by South Africa’s health department. Candice Sehoma, advocacy advisor for MSF Access in Southern Africa, says she would be surprised if the country avoids it.
It’s part of a concerning pattern of shortages of essential medicines worldwide, she says.
“We’re seeing more and more companies deprioritising insulin and discontinuing affordable medicines,” says Sehoma.
When there’s insulin but no food
While his stock of test strips lasts, Mazibuko takes them along when he visits members of his support group in Hluvukani.
They could technically find matching strips in the private sector, but they’re likely to be too expensive. A 2024 study found that for someone earning South Africa’s minimum wage, a single blood-sugar test in the private sector costs more than an hour of work, and a month of basic diabetes supplies can swallow three full days’ wages.
Many of the people on Mazibuko’s route are facing far more serious problems than the loss of glucometers. Those who aren’t working are often not taking their medication well either, Mazibuko says. “They don’t have food so they skip breakfast and also skip their insulin because they’re scared.”
Injecting insulin on an empty stomach can cause a sudden blood sugar crash that could lead to dizziness, confusion or a seizure.
Mazibuko is working on a skills programme to help these people make a living that might also protect them from lapses in basic supplies at government health facilities, which he claims happens often.
“Sometimes you go to the clinic, they tell you that they’ve run out of insulin, or they tell you to buy your own needles and syringes. You will have to do that with borrowed money,” says Mazibuko.
The Mpumalanga health department also did not respond to Spotlight’s requests for comment.
Republished from Spotlight under a Creative Commons licence.
Findings could lead to new treatments to improve metabolic health and reduce risks of obesity, diabetes
This image shows the seipin-adipogenin complex that is a critical driver of lipid droplet formation in fat cells. Credit: UT Southwestern Medical Center
A microprotein called adipogenin appears to play a key role in helping fat cells store lipid droplets – a phenomenon that’s pivotal for metabolic health, a study co-led by UT Southwestern Medical Center researchers shows. The findings, published in Science, could lead to new strategies to improve healthy lipid storage, which in turn may reduce risks of obesity, diabetes, and other metabolic conditions.
“This study builds upon our long-standing interest in how fat cells maintain their cellular health upon expansion. We show that a tiny microprotein punches far above its weight in sculpting fat biology,” said Philipp Scherer, PhD, Professor of Internal Medicine and Cell Biology and Director of the Touchstone Center for Diabetes Research at UT Southwestern.
Dr Scherer led the study with co-first authors Chao Li, PhD, and Xue-Nan Sun, PhD, Instructors of Internal Medicine at UTSW, and co-senior author Elina Ikonen, MD, PhD, Professor of Anatomy at the University of Helsinki.
After every meal, Dr Scherer explained, any lipids that aren’t burned immediately for energy must be stored in the body. The most common and healthy place to store lipids is in fat cells, or adipocytes, which stockpile these nutrients as droplets, much like oil forms droplets in water. Lipids stored in other cell types can cause a condition called lipotoxicity, spurring cell damage and cell death.
Previous research at UTSW and elsewhere has shown that a protein called seipin is critical for healthy lipid storage in a diverse range of organisms, including plants, fungi, and mammals. But how seipin accomplishes this feat has been unclear. Some studies have suggested that adipogenin – a small protein made of only 80 amino acids as compared with the hundreds found in seipin – is also important for lipid storage, but its exact function was unknown.
To answer these questions, the researchers isolated adipogenin along with its interacting proteins from mice, which produce a form of this microprotein that’s nearly identical to the one in humans. The most common binding partner for adipogenin turned out to be seipin.
Using cryo-electron microscopy, a technique that can image molecules at the atomic level, researchers showed that adipogenin appeared to reinforce seipin’s structure, making it more rigid and stable. Working with mouse models that overproduced adipogenin, the scientists found that their fat cells held significantly larger lipid droplets. They also stored considerably more fat than unaltered mice. In contrast, mouse models that produced no adipogenin had much smaller lipid droplets in their fat cells and less fat overall.
“This study nudges us a little closer to the clinic by revealing a brand-new handle on how fat cells store lipids, which matters enormously for obesity, diabetes, lipodystrophy, and fatty liver disease,” Dr Scherer said. “Adipogenin becomes a druggable lever on seipin’s machinery, with the promise to either dampen harmful fat buildup or boost healthy adipose storage when needed.”
A growing body of evidence implicates cellular senescence – when cells age and permanently stop dividing – as an important contributor to metabolic dysfunction that can lead to obesity, type 2 diabetes, and metabolic syndrome. A review in the Journal of Internal Medicine explores the research connecting senescent cells to metabolic diseases and highlights the potential of “senotherapeutics” in treatment strategies.
The authors note that senescent cells accumulate in metabolic tissues where they secrete factors that disrupt tissue function by promoting inflammation and fibrosis. With this information, investigators have developed senotherapeutic interventions that include senolytics (which eliminate senescent cells), senomorphics (which suppress factors secreted by senescent cells), and senosensitisers (which render senescent cells more vulnerable to clearance).
“By targeting senescent cells, senotherapeutics mitigate one of the root drivers of age- and obesity-related metabolic disease, opening a powerful new frontier in modern medicine,” said corresponding author Allyson Palmer, MD, PhD, of the Mayo Clinic. “This emerging class of therapies could transform how we treat and even prevent metabolic disease.”
Underweight patients may face higher risk of poor outcomes after surgery
Source: Pixabay CC0
Higher BMI is not linked to increased risk of death or other complications following shoulder replacement surgery, according to a new study by Epaminondas Markos Valsamis from the University of Oxford, UK, and colleagues publishing November 20th in the open-access journal PLOS Medicine.
Joint replacement surgeries – including hip, knee and shoulder replacements – can significantly improve quality of life. Many patients with obesity are denied these procedures despite a lack of formal recommendations from national organisations. Evidence on the risks of joint replacement surgery in patients with obesity is limited and mixed.
In this study, researchers analysed more than 20 000 elective shoulder replacement surgeries performed across the UK and Denmark to see whether BMI was associated with death or other complications.
Compared to patients with a healthy BMI (21.75 kg/m2), patients with obesity (BMI 40 kg/m2) had a 60% lower risk of death within the year following surgery. Those considered underweight (BMI <18.5 kg/m2) had a slightly higher risk of death. The study does not support restricting patients with a high BMI from having elective shoulder replacement surgery, contrary to evidence that some hospitals are starting to restrict patients.
One main limitation of this study was the small sample size of the underweight population (131 for the UK data, 70 for the Denmark data). However, this was a large study that consistently showed a lower risk of death and complications in patients with obesity undergoing shoulder replacement surgery across multiple outcomes and two countries. The results can help patients, surgeons, and policymakers make informed decisions about who should be considered fit for these surgeries.
Lead author Epaminondas Markos Valsamis says, “Shoulder replacements offer patients the opportunity for excellent pain relief and improved quality of life. Our research shows that patients with a higher BMI do not have poorer outcomes after shoulder replacement surgery.”
Senior author Professor Jonathan Rees adds, “While BMI thresholds have been used to limit access to joint replacement surgery, our findings do not support restricting higher BMI patients from accessing shoulder replacement surgery.”
Researchers tracked 85 young adults over a four-year period, finding that increases in ultra-processed food consumption were linked with elevated blood sugar and early signs of diabetes risk.
Photo by Jonathan Borba
More than half of calories consumed in the United States come from ultra-processed foods (UPFs), items like fast food and packaged snacks that are often high in sodium, sugar and unhealthy fats. In adults, research has clearly linked these foods to type 2 diabetes and other conditions, but few studies have explored their effects among youth.
Now, researchers from the Keck School of Medicine of USC have completed one of the first studies to examine the link between UPF consumption and how the body processes glucose, which is known to predict diabetes risk. By tracking changes over time, they gained insights into how dietary choices may influence key biological processes.
The researchers studied a group of 85 young adults over a four-year period. They found that an increase in UPF intake was associated with a higher risk for prediabetes, or early-stage high blood sugar that can lead to diabetes. Eating more UPFs was also linked to insulin resistance, where the body becomes less effective at using insulin to control blood sugar. The study, funded in part by the National Institutes of Health, was just published in the journal Nutrition and Metabolism.
“Our findings show that even modest increases in ultra-processed food intake can disrupt glucose regulation in young adults at risk for obesity. These results point to diet as a modifiable driver of early metabolic disease, and an urgent target for prevention strategies among young people,” said senior author Vaia Lida Chatzi, MD, PhD, a professor of population and public health sciences and paediatrics and director of the ShARP Center at the Keck School of Medicine.
Early adulthood is a formative stage where people have reached physical maturity and are building habits that can persist for years. Trading packaged or restaurant meals for whole and raw foods like fruits, vegetables, and whole grains can reduce the likelihood of developing type 2 diabetes later in life.
“Young adulthood is a critical window for shaping long-term health,” Chatzi said. “By focusing on young adults, we have an opportunity to intervene early, before prediabetes and other risk factors become lifelong conditions.”
Signs of prediabetes
The research included 85 young adults from the Metabolic and Asthma Incidence Research (Meta-AIR) study, part of the broader Southern California Children’s Health Study. Participants, aged 17–22, provided data at a baseline visit between 2014 and 2018 and a follow-up visit approximately four years later.
At each visit, participants reported everything they had eaten on one recent weekday and one recent weekend day. Researchers classified foods into two categories: UPFs (such as candy, soda, cereal, packaged spreads, flavored yogurts, and many restaurant foods) and foods that were not ultra-processed. They then calculated what percentage of each participant’s daily caloric intake came from UPFs.
The researchers also collected blood samples from participants before and after they consumed a sugary drink to test how effectively their body responded to blood sugar with insulin. They then conducted a statistical analysis to compare dietary changes with signs of prediabetes, adjusting for differences in age, sex, ethnicity and physical activity levels.
From baseline to follow-up, a 10% increase in UPF consumption was associated with a 64% higher risk for prediabetes and a 56% higher risk for problems with glucose regulation. Participants who reported eating more UPFs at their initial visit were also more likely to have elevated insulin levels at follow-up—an early sign of insulin resistance, where the body must produce more insulin to keep blood sugar in a healthy range.
Limiting ultra-processed foods
The study shows that the risks of UPFs extend to young adults, a group often overlooked in previous research.
“These findings indicate that ultra-processed food consumption increases the risk for pre-diabetes and type 2 diabetes among young adults – and that limiting consumption of those foods can help prevent disease,” said the study’s first author, Yiping Li, a doctoral student in quantitative biomedical sciences at Dartmouth College who previously worked as a researcher at the Keck School of Medicine.
Future studies with larger groups and more detailed diet tracking can help clarify which foods pose the greatest risk for young adults, the researchers said. They also plan to continue investigating the biological mechanisms behind these links, including how specific nutrients in UPFs may influence insulin and blood sugar regulation.
A new University of California San Diego study offers compelling evidence that GLP-1 receptor agonists may do more than regulate blood sugar and weight. In an analysis of more than 6800 colon cancer patients across all University of California Health sites, researchers found that those taking glucagon-like peptide-1 (GLP-1) medications were less than half as likely to die within five years compared to those who weren’t on the drugs (15.5% vs 37.1%).
The study, led by Raphael Cuomo, PhD, used real-world clinical data from the University of California Health Data Warehouse to assess outcomes across the state’s academic medical centres. After adjusting for age, body mass index (BMI), disease severity and other health factors, GLP-1 users still showed significantly lower odds of death, suggesting a strong and independent protective effect.
The survival benefit appeared most pronounced in patients with very high BMI (over 35), hinting that GLP-1 drugs may help counteract the inflammatory and metabolic conditions that worsen colon cancer prognosis. Researchers believe several biological mechanisms could explain the link. Beyond regulating blood sugar, GLP-1 receptor agonists reduce systemic inflammation, improve insulin sensitivity and promote weight loss – all factors that can dampen tumour-promoting pathways. Laboratory studies also suggest that GLP-1 drugs may directly prevent cancer cell growth, trigger cancer cell death and reshape the tumour microenvironment. However, the study authors emphasise that more research is needed to confirm these mechanisms and determine whether the survival benefit observed in this real-world analysis represents a direct anti-cancer effect or an indirect result of improved metabolic health.
Cuomo notes that while these results are observational, they underscore an urgent need for clinical trials to test whether GLP-1 drugs can improve cancer survival rates, especially for patients with obesity-related cancers.
Mass General Brigham researchers used real-world data to conduct a head-to-head study to investigate cardioprotective effects, finding both medications reduced risk.
Pexels Photo by Freestocksorg
A new study from Mass General Brigham provides head-to-head evidence comparing the cardioprotective effects of tirzepatide and semaglutide. The researchers found both medications reduced the risk of heart attack, stroke, and death from any cause. The study is published in Nature Medicine, with results simultaneously presented at the American Heart Association Scientific Sessions 2025.
Previous research shows that semaglutide protects against cardiovascular events like heart attack or stroke. But it wasn’t clear if tirzepatide, also commonly prescribed for type 2 diabetes, has the same cardiovascular benefits.
Researchers used US claims databases to compare the cardiovascular outcomes of nearly one million adults taking tirzepatide, semaglutide, or other medications for type 2 diabetes.
“Randomised controlled trials are often considered the reference standard in the medical evidence generation process. However, not all questions can be answered using this time- and resource-intensive method,” said first author Nils Krüger, MD, a research fellow in the Division of Pharmacoepidemiology and Pharmacoeconomics in the Mass General Brigham Department of Medicine. “Data generated in clinical practice and used secondarily for research allow us to address a wide range of clinically relevant questions time- and resource-effectively – when applied correctly. Moreover, we can study patients who reflect the reality of everyday clinical care, in contrast to the highly selected participants of randomized experiments.”
The study demonstrated a cardiovascular benefit for patients at risk for adverse cardiovascular events who had type 2 diabetes. Compared with sitagliptin, a diabetes drug that has shown neutral effects on cardiovascular outcomes, semaglutide reduced the risk of stroke and heart attack by 18 percent. Treatment with tirzepatide lowered the risk of stroke, heart attack, and death by 13 percent compared to dulaglutide, another GLP-1 receptor agonist that has been available for many years.
“Both drugs show strong cardioprotective effects. Our data also indicate that these benefits occur early, suggesting that their protective mechanisms go beyond weight loss alone,” said Krüger. The exact biological mechanisms underlying these protective effects remain unknown.
Because these medications have only recently become available, studies confirming their cardioprotective mechanisms – particularly those directly comparing the two dominant GLP-1 agents, tirzepatide and semaglutide – are still lacking.
“According to recently presented database analyses by the respective manufacturers, each company’s own drug appears to reduce cardiovascular risk much more effectively than the competitor’s,” said Krüger. “However, our study found only small differences between tirzepatide and semaglutide in cardiovascular protection among populations at risk of adverse events, underscoring that both agents provide protective benefit and could be integrated into clinical cardiovascular practice.”
“We hope that our study will help clinicians better understand how these new medications work in clinical practice. Our transparent and open science practices, including pre-registration of a public protocol and shared analytic code, are designed to support scientific discussion,” said last author Shirley Wang, PhD, an associate epidemiologist in the Division of Pharmacoepidemiology and Pharmacoeconomics in the Mass General Brigham Department of Medicine.
Johannesburg, 11 November 2025:As we approach World Diabetes Day on November 14, civil society organisations warn that the cost of inaction on non-communicable diseases (NCDs) such as diabetes is already being paid for in lives, livelihoods and lost potential. The Healthy Living Alliance (HEALA) is calling on the South African government to increase the Health Promotion Levy (HPL) on sugary drinks from 11% to 20%, to help curb sugary drinks consumption and reduce the financial burden on the health system from rising non-communicable diseases.
“Diabetes is now the second leading cause of death in South Africa,1 yet every year we allow preventable diseases to claim more lives,” says Nzama Mbalati, CEO of HEALA. “Raising the Health Promotion Levy is one of the simplest, most effective steps government can take to protect people’s health, especially children, who are consuming sugar at dangerous levels.”
Since the introduction of the HPL in 2018, beverage companies have reduced the sugar content of their drinks, leading to cuts in average per-capita sugar consumption. But the gains have stalled. HEALA and its partners warn that without further cuts in consumption, the policy’s impact will fade, while rates of diabetes will continue to climb.
South Africa’s obesity rate is already twice the global average, and even one sugary drink a week raises a child’s risk of obesity and diabetes.2,3 One in four diabetes cases in the country is caused by sugary drink consumption.4 These numbers are not just statistics; they represent real people and families forced to navigate lifelong illness and financial hardship.
The economic toll is equally alarming. Treating obesity related conditions such as diabetes already costs South Africa more than R33 billion each year or about 15% of total government health spending.5 Modelling by PRICELESS SA (University of the Witwatersrand) shows that increasing the levy to 20% could save approximately 72 000 lives and prevent 85 000 strokes over two decades while easing the fiscal pressure on a health system already stretched beyond capacity.5
HEALA’s new national campaign, which launched in November, brings this message to the fore in two phases. The first calls for stronger health taxes across sugary drinks, alcohol and tobacco, continuing South Africa’s proven track record of using taxation to advance public health. The second sharpens focus on raising the HPL, calling for its increase as part of a consistent, evidence-based approach to protecting lives.
Through personal stories of South Africans living with diabetes, the campaign reveals the real cost of inaction and unites civil society under the banner #OneVoice, calling on government to put public health before profit.
Alphinah Setumo, a 52-year-old mother from Mathibestad, lost both her legs and her eyesight after years of consuming sugary drinks without understanding the risks. “Back then, drinking two litres of a sugary drink a day was nothing,” she recalls. “If I had known what I know now, my life would be different.”
Mpho Thebe, a maths and science tutor from Kroonstad, tells a similar story. Once a daily consumer of fizzy drinks, he lost his left leg to diabetes at 45. Today, he walks with a prosthetic leg and teaches children about perseverance and prevention. “I thought sugar was harmless,” he says. “Now I know it can take everything from you.”
These stories mirror thousands of others across the country, where diabetes silently devastates families, especially in low-income communities where affordable, healthy food and clean water remain scarce.
The campaign, supported by actress and mother Samela Tyelbooi, urges government to act. “As a parent, I worry about how sugar can make my kids sick,” says Tyelbooi. “We need government to increase the HPL, protect our children’s future, and stop putting profit before people.”
HEALA’s coalition partners, including health advocates, researchers and civil society organisations, are speaking with one voice ahead of the Medium-Term Budget Policy Statement and the 2026 Budget Speech. Their collective message is clear: the HPL is not just another tax, it’s a health tax, like those on alcohol and tobacco, designed to save lives, prevent disease and safeguard South Africa’s future.
“This is not about taking away people’s choices, it’s about giving South Africans the chance to make healthier, more informed choices,” adds Mbalati.
Diabetes and other NCDs already account for over 50% of deaths from preventable diseases in South Africa.5,6 Without decisive fiscal measures, the burden will continue to fall on the households least able to bear it.
Globally, countries from Mexico to the UK have proven that health taxes reduce sugar consumption and improve health outcomes.
HEALA is urging citizens to join the call by signing the petition and demanding that government increase the HPL to 20%.
“We have the evidence, we have the stories, and we have the will,” concludes Tyelbooi. “Now we need action.”
