People with the most weight loss in the first year were most likely to achieve sustained remission
Photo by Andres Ayrton on Pexels
A new study finds that very few patients diagnosed with type 2 diabetes are able to achieve normal blood glucose levels through weight loss alone. A team led by Andrea Luk of the Chinese University of Hong Kong, report these findings January 23rd in the open access journal PLOS Medicine.
Clinical trials suggest that people with type 2 diabetes can control their blood glucose levels without medication if they lose weight and keep it off. However, it is unknown how many patients can achieve remission through weight loss alone under real-world conditions. In the new study, researchers looked at 37 326 people in Hong Kong who were newly diagnosed with type 2 diabetes to see whether – and low long – patients could control the disease through weight loss.
The researchers discovered that only 6% of people achieved diabetes remission solely through weight loss by about eight years after diagnosis. For people who initially achieved remission, two-thirds had elevated blood glucose levels by three years after diagnosis. These rates are significantly lower than in clinical trials, where remission occurred in up to 73% of patients at one year post-diagnosis. People with the greatest weight loss in the first year were most likely to have sustained remission.
The study shows that controlling type 2 diabetes through sustained weight loss is possible in real-world settings, but that few patients will achieve normal blood glucose levels through weight management alone, especially over the long-term. One reason for the discrepancy with clinical trials is that trial participants receive intensive lifestyle interventions, including holistic support for dietary changes, physical exercise and mental health. The researchers conclude that patients should receive early weight management interventions as a way to increase the odds that they will achieve sustained remission. Furthermore, the data suggest that early weight management interventions increase the odds of sustained remission and that sustained lifestyle changes are likely to be paramount.
Luk adds, “Greater weight loss within the first year of diabetes diagnosis was associated with an increased likelihood of achieving diabetes remission. However, the incidence of diabetes remission was low with only 6% of people achieving remission over 8 years, and half of those with initial remission returned to hyperglycaemia within 3 years indicating poor sustainability of diabetes remission in real-world setting.”
Scientists have developed a ‘smart’ insulin which can be taken orally. The insulin is encapsulated within tiny nano-carriers, 1/10 000th the width of a human hair. The results of its testing in baboons were recently published in Nature Nanotechnology.
“This way of taking insulin is more precise because it delivers the insulin rapidly to the areas of the body that need it most. When you take insulin with a syringe, it is spread throughout the body where it can cause unwanted side effects,” explains Professor Peter McCourt at UiT Norway’s Arctic University. He is one of the researchers behind the study.
Delivered insulin to where it’s needed
It was researchers at the University of Sydney and Sydney Local Health District who, in collaboration with UiT, discovered many years ago that it was possible to deliver medicines via nano-carriers to liver. The method has then been further developed in Australia and in Europe.
Many medicines can be taken orally, but until now people have had to inject insulin into the body. McCourt explains that the problem with insulin with a nano-carrier is that it breaks down in the stomach and thus does not get to where it is needed in the body. This has been a major challenge for developing a diabetes medicine that can be taken orally.
But now the researchers have solved this challenge.
“We have created a coating to protect the insulin from being broken down by stomach acid and digestive enzymes on its way through the digestive system, keeping it safe until it reaches its destination, namely the liver,” says McCourt, who is a liver biologist.
The coating is then broken down in the liver by enzymes that are active only when the blood sugar levels are high, releasing the insulin where it can then act in the liver, muscle, and fat to remove sugar from the blood.
“This means that when blood sugar is high, there is a rapid release of insulin, and even more importantly, when blood sugar is low, no insulin is released,” says Nicholas J. Hunt at the University of Sydney who, together with Victoria Cogger, leads the project.
He explains that this is a more practical and patient-friendly method of managing diabetes because it greatly reduces the risk of a low blood sugar event occurring, namely hypoglycaemia and allows for the controlled released of insulin depending on the patient’s needs, unlike injections where all the insulin is released in one shot.
Fewer side effects
The new method works similarly to how insulin works in healthy people. The pancreas produces insulin which first passes through the liver where a large portion of it is absorbed and maintains stable blood sugar levels. In the new insulin method, the nano-carrier releases insulin in the liver, where it can be taken up or enter the blood to circulate in the body.
When insulin is injected subcutaneously, far more of it goes to the muscles and to adipose tissues that would normally happen if it was released from the pancreas, which can lead to fat accumulation. It can also lead to hypoglycaemia.
With the new method, there will be fewer such side effects, and no need for injection – or refrigeration.
Tested on baboons
The oral insulin has been tested on nematodes, on mice and rats. And lastly, the medicine has now been tested on baboons in the National Baboon Colony in Australia.
“In order to make the oral insulin palatable we incorporated it into sugar-free chocolate, this approach was well received” says Hunt.
He says that 20 baboons have taken part in this study. When they received the medicine, their blood sugar was lowered.
The baboons were normal, healthy baboons, but the oral insulin have also been tested on mice and rats that actually have diabetes. The mice and rats did not have hypoglycaemic events, gain weight or fat accumulation in the liver overcoming current challenges with injectable and other oral insulins.
What remains now is to test the new method on humans.
Ready for use in 2-3 years
“Trials on humans will start in 2025 led by the spin out company Endo Axiom Pty Ltd. Clinical trials are performed in 3 phases; in the phase I trial we will investigate the safety of the oral insulin and critically look at the incidence of hypoglycaemia in healthy and type 1 diabetic patients. Our team is very excited to see if we can reproduce the absent hypoglycaemia results seen in baboons in humans as this would be a huge step forward. The experiments follow strict quality requirements and must be carried out in collaboration with physicians to ensure that they are safe for the test subjects” says Hunt.
Photo by Andrea Piacquadio: https://www.pexels.com/photo/woman-in-gray-tank-top-3812757/
A new study from the University of Zurich (UZH) has revealed that the complement system plays an important role in Long Covid, a common sequela of SARS-CoV-2 infection. The findings, published in Science, show that the complement system ends up damaging tissue and blood cells even after the original infection has ended.
A significant proportion of individuals infected with SARS-CoV-2 develop long-lasting symptoms with a wide range of manifestations. The causes and disease mechanisms of Long Covid are still unknown, and there are no diagnostic tests or targeted treatments.
Part of the immune system active for too long
A team of researchers led by Onur Boyman, professor of immunology at UZH and Director of the Department of Immunology at the University Hospital Zurich (USZ), has implicated the complement system. It is part of the innate immune system and normally helps to fight infections and eliminate damaged and infected body cells.
“In patients with Long Covid, the complement system no longer returns to its basal state, but remains activated and, thus, also damages healthy body cells,” says Boyman.
Continued activation of complement system damages tissue and blood cells
The researchers followed 113 COVID patients for up to one year after their acute SARS-CoV-2 infection and compared them with 39 healthy controls.
After six months, 40 patients had active Long Covid disease.
More than 6500 proteins in the blood of the study participants were analysed both during the acute infection and six months later.
“The analyses of which proteins were altered in Long Covid confirmed the excessive activity of the complement system. Patients with active Long Covid disease also had elevated blood levels indicating damage to various body cells, including red blood cells, platelets and blood vessels,” explains Carlo Cervia-Hasler, a postdoctoral researcher in Boyman’s team and first author of the study.
Bioinformatics recognises protein patterns
The measurable changes in blood proteins in active Long Covid indicate an interaction between proteins of the complement system, which are involved in blood clotting and the repair of tissue damage and inflammation.
In contrast, the blood levels of Long Covid patients who recovered from the disease returned to normal within six months.
Active Long Covid is therefore characterised by the protein pattern in the blood.
The blood markers were discovered using bioinformatics methods in collaboration with Karsten Borgwardt during his time as a professor at ETH Zurich.
“Our work not only lays the foundation for better diagnosis, but also supports clinical research into substances that could be used to regulate the complement system. This opens up new avenues for the development of more targeted therapies for patients with Long Covid,” Onur Boyman said.
Patients with Guillain-Barré syndrome (GBS) face a rare and heterogeneous disorder of the peripheral nervous system that is often triggered by preceding infections and causes severe muscle weakness. In Europe and the USA, around 1 to 2 cases per 100 000 people occur every year.
Although GBS is considered an autoimmune disease, the underlying mechanisms remain largely unknown, making an accurate diagnosis and effective treatment a challenge.
A recent study published in the journal Nature, has revealed a pivotal aspect of GBS pathophysiology.
The work, led by Daniela Latorre, an SNSF PRIMA group leader at the Institute of Microbiology at ETH Zurich, investigated autoimmune factors that are potentially responsible for this illness in close collaboration with clinical scientists at the University Hospital Zurich and the Neurocenter of Southern Switzerland (EOC) in Lugano.
GBS usually begins with weakness and tingling in the legs, which can then spread to the arms and upper body, making it difficult to walk or move. In severe cases, paralysis can affect respiration.
Autoreactive T cells target peripheral nerves
By employing sensitive experimental approaches, Latorre’ s group was able to reveal that in GBS patients, specific cells of the immune system known as T lymphocytes invade the nerve tissue and target the insulating covering of nerve fibres called myelin.
Normally, T lymphocytes play a vital role in our immune system by identifying and eliminating threats like infections and abnormal cells.
However, in rare cases, they can mistakenly attack the body’s own tissues, leading to autoimmune diseases.
“We found that these autoreactive T lymphocytes were exclusive to patients with a type of GBS characterised by nerve demyelination and showed a specific disease-associated signature, distinguishing them from healthy individuals,” Latorre explains.
These findings mark the first evidence of the contribution of autoreactive T lymphocytes to the disease in humans.
Furthermore, the researchers identified T lymphocytes reactive to both self-antigens of peripheral nerves (myelin) and viral antigens in a subset of post-viral GBS patients, supporting a direct link between disease development and triggers of a preceding infection.
Current treatments are effective for many GBS patients, but they lack specificity, and around 20% of patients remain severely disabled or die. Overall, the work of the research team offers novel insights into our understanding of GBS, opening avenues for further investigations on larger patient groups to decipher immune mechanisms in different GBS variants. This new knowledge could lead to targeted therapies for specific GBS subtypes, potentially improving patient care.
One in three children who fall ill from bacterial meningitis go on to live with permanent neurological disabilities due to the infection. This is according to a new epidemiological study led by Karolinska Institutet and published in JAMA Network Open. This marks the first time that researchers have identified the long-term health burden of bacterial meningitis.
The bacterial infection can currently be cured with antibiotics, but it often leads to permanent neurological impairment. And since children are often affected, the consequences are significant.
“When children are affected, the whole family is affected. If a three-year-old child has impaired cognition, a motor disability, impaired or lost vision or hearing, it has a major impact. These are lifelong disabilities that become a major burden for both the individual and society, as those affected need health care support for the rest of their lives,” says Federico Iovino, associate professor in Medical Microbiology at the Department of Neuroscience, Karolinska Institutet, and one of the authors of the current study.
By analyzing data from the Swedish quality register on bacterial meningitis between 1987 and 2021, the researchers have been able to compare just over 3500 people who contracted bacterial meningitis as children with just over 32 000 matched controls from the general population, with an average follow-up time of over 23 years.
The results show that those diagnosed with bacterial meningitis consistently have a higher prevalence of neurological disabilities such as cognitive impairment, seizures, visual or hearing impairment, motor impairment, behavioural disorders, or structural damage to the head.
The risk was highest for structural head injuries – 26 times greater, hearing impairment – almost eight times greater, and motor impairment almost five times greater.
About one in three people affected by bacterial meningitis had at least one neurological impairment compared to one in ten among controls.
“This shows that even if the bacterial infection is cured, many people suffer from neurological impairment afterwards,” says Federico Iovino.
With the long-term effects of bacterial meningitis identified, Federico Iovino and his colleagues will now move forward with their research.
“We are trying to develop treatments that can protect neurons in the brain during the window of a few days it takes for antibiotics to take full effect. We now have very promising data from human neurons and are just entering a preclinical phase with animal models. Eventually, we hope to present this in the clinic within the next few years,” says Federico Iovino.
The 2024 Top Employers have been announced and GEMS (Government Employees Medical Scheme) has again been recognised as a Top Employer in South Africa.
Being certified as a Top Employer showcases an organisation’s dedication to a better world of work and exhibits this through excellent HR policies and people practices.
GEMS Principal Officer, Dr Stan Moloabi says this of the accolade, “The Scheme takes immense pride in this achievement as we believe in the adage, ‘batho pele’– people first.” He adds, “It is our focus on investing in our more than 400 employees that enables us to fulfil our mission to provide all members with equitable access to affordable and comprehensive healthcare; promoting member wellbeing.”
The Top Employers Institute programme certifies organisations based on the participation and results of their HR Best Practices Survey. This survey covers six HR domains consisting of 20 topics including People Strategy, Work Environment, Talent Acquisition, Learning, Diversity, Equity & Inclusion, Wellbeing and more.
To the Scheme, it is heartwarming that it is the third year in a row that it has received this recognition.
Top Employers Institute CEO David Plink says: “Exceptional times bring out the best in people and organisations. And we have witnessed this in our Top Employers Certification Programme this year: exceptional performance from the certified Top Employers 2024. These employers have always shown that they care for the development and well-being of their people. By doing so, they collectively enrich the world of work. We are proud to announce and celebrate this year’s group of leading people-oriented employers: the Top Employers 2024.”
The programme has certified and recognised over 2 300 Top Employers in 121 countries/regions across five continents.
Older adults require more protein but eat less than younger people, making it a challenge for them to maintain muscle mass. Eating a meal with meat ensures that muscle proteins are built faster than a vegan meal with the same amount of protein. This study, published in The Journal of Nutrition, was the first to compare the speed at which muscle proteins are being made after eating a complete meal with animal or plant proteins.
Every two to three months the proteins in human muscle are completely renewed. In order to make muscle proteins, we need protein from food, for example from animal sources such as meat, cheese and yoghurt, or from plant products such as beans, nuts and soymilk. Previous research on protein powders showed that animal proteins have better muscle-building properties than plant proteins. “But in reality, we do not get our proteins in powder form, but through complete meals,” says study author and PhD student Philippe Pinckaers. “Those meals contain different types of protein and other nutrients such as fibres, fats and carbohydrates. These nutrients affect how proteins are released from the diet and influences the making of muscle proteins.”
To investigate how muscles respond after eating a complete meal, Pinckaers asked 16 participants aged over 65 to come to the lab twice for a dinner meal.
Dining out in the lab
On one day, the participants sat down to a meal with quinoa with chickpeas, broad beans, soy beans and soy sauce was on the menu, while on the other day the menu consisted of a beef tartlet, potatoes, green beans, apple sauce and herb butter. Both meals had similar amounts of protein, fat, carbohydrates and calories. Prior to the meals, participants were administered an infusion of special amino acids.
“The amino acids administered via the infusion were marked, as it were with a flag,” Pinckaers explains. “We took small pieces of muscle tissue from the participants and were able to measure the amount of ‘flags’ in them. If more flags are measured, it means that muscle proteins are built up faster, which is beneficial for muscles. In this way, we found that after eating a meal with animal protein, muscle protein was built up faster than after eating a vegan meal. This means that a vegan meal does not have the same capacity to make muscle proteins as a meal that includes animal proteins.” This difference arises partly because plant-based foods are harder to digest, and because they naturally contain fewer essential amino acids.
Context is key
The results do not mean that everyone should eat meat or other animal products, clarifies professor of exercise science and lead researcher Luc van Loon. “Healthy people can very well compensate for the lower quality of plant proteins by eating more of them.” For elderly or frail patients it is a bit more complicated. “Elderly people actually need more protein in order to reach the same level of muscle protein synthesis, when compared to young individuals. However, they actually eat less. Also, patients with reduced appetite or who do not exercise much, for example during hospitalisation, may have trouble consuming a sufficient amount of protein. For them, it is therefore important to choose protein sources that stimulate the making of muscle proteins as much as possible. The best sources in this situation would be proteins from animal products.”
There is a well-known relationship between good physical fitness at a young age and a lower risk of cardiovascular disease later in life. But when researchers adjusted for familial factors by means of sibling analysis, they found a weaker association, although the link between high body mass index (BMI) and cardiovascular disease remained strong. The study, which was conducted by researchers from Karolinska Institutet and other universities, is published in JAMA Network Open.
“This does not mean that fitness is irrelevant,” cautions the study’s last author Viktor Ahlqvist, doctoral student at the Department of Global Public Health, Karolinska Institutet. “We could still see an association, although it was weaker after taking into account factors shared by full siblings. We also think that adolescence is an important time in life for establishing good habits such as exercising and having a healthy diet.”
Many observational studies have previously demonstrated links between various risk factors at a young age and cardiovascular disease in adulthood. However, whether the associations are causal is challenging to prove because of the potential influence of unaccounted genetic and environmental factors. A collaborative team including researchers from Karolinska Institutet in Sweden has therefore tried to examine if a large proportion of cardiovascular diseases in adulthood could indeed be prevented with a lower BMI, lower blood pressure, improved physical fitness or improved muscle strength in adolescence.
Data from the Military Conscription Register
Sourcing data from the Swedish Military Conscription Register and other Swedish registries, the researchers identified over a million 18-year-old males and followed them for 60 years. Almost half of them were full brothers.
“The strength of our study, which makes it more reliable than many other conventional observational studies, is that we have used sibling analyses,” says the study’s first author Marcel Ballin, researcher at Uppsala University and analyst at Region Stockholm’s Centre for Epidemiology and Community Medicine. “By doing so we could examine how the relationship changes when controlling for all shared sibling factors. This includes environmental factors such as childhood environment and half of the genetics.”
The results show that a high BMI in late adolescence was strongly associated with future cardiovascular disease, even after the researchers had controlled for shared familial factors. However, the association between physical fitness and cardiovascular disease was considerably weaker in the sibling analysis, suggesting that many previous observational studies might have overestimated the relevance of adolescent fitness to cardiovascular health later in life.
High BMI the strongest risk factor
“Our conclusion is that of the risk factors studied, high BMI is the strongest individual risk factor for cardiovascular disease, and that efforts to tackle the obesity epidemic should continue to be given high priority,” says co-author Daniel Berglind, docent at the Department of Global Public Health, Karolinska Institutet. “A good level of fitness and muscle strength in adolescence doesn’t seem as crucial, but physical activity still remains important for public health, as it can bring other health benefits.”
The study examined the association between risk factors at a young age and future cardiovascular disease; other disease outcomes were not investigated. The researchers had no data on whether the participants’ risk factors varied later in life, and they only studied men, which makes it difficult to extend their findings to women. The Military Conscription Register also lacks details on certain risk factors for future cardiovascular disease, such as diet, alcohol consumption, smoking, blood lipids and blood glucose.
The researchers received no specific grant for this study. Co-author Martin Neovius is on the advisory panels for Ethicon, Johnson & Johnson and Itrim and has been a consultant for the Swedish armed forces outside the scope of this study. No other conflicts of interest have been reported.
Deaths from breast cancer dropped 58% between 1975 and 2019 due to a combination of screening mammography and improvements in treatment, according to a new study led by Stanford Medicine clinicians and biomedical data scientists.
Nearly one-third of the decrease (29%) is due to advances in treating metastatic breast cancer, also known as stage 4 breast cancer or recurrent cancer. Although these advanced cancers are not considered curable, women with metastatic disease are living longer than ever.
The analysis helps cancer researchers assess where to focus future efforts and resources.
“We’ve known that deaths from breast cancer have been decreasing over the past several decades, but it’s been difficult or impossible to quantify which of our interventions have been most successful, and to what extent,” said Jennifer Caswell-Jin, MD, assistant professor of medicine. “This type of study allows us to see which of our efforts are having the most impact and where we still need to improve.”
Caswell-Jin and Liyang Sun are co-first authors of the study, which was published in the Journal of the American Medical Association. Sylvia Plevritis, PhD, professor and chair of biomedical data science, and Allison Kurian, MD, MSc, professor of medicine and of epidemiology and population health, are co-senior authors.
The study was a collaborative effort by a national consortium of researchers called CISNET, or the Cancer Intervention and Surveillance Modeling Network. CISNET was established in 2000 by the National Cancer Institute to understand the impact of cancer surveillance, screening and treatment on incidence and mortality. Doing so requires sophisticated computer algorithms capable of modelling the natural course of the disease and the typical treatment paths of individual patients, then translating that information to population-level data collected by the national Surveillance, Epidemiology, and End Results Program, or SEER registry, from 1975 to 2019.
The study is the third in a trio of papers from CISNET published since 2005 that assess the relative contributions of regular screening and treatment advances on breast cancer deaths. The previous two papers informed national guidelines and helped cancer researchers focus their efforts on the most intractable problems.
“Twenty years ago, there was a question whether routine screening mammography actually decreased the number of deaths from breast cancer,” Plevritis said. But in 2005, she and other CISNET researchers published a paper in the New England Journal of Medicine that conclusively demonstrated that screening was responsible for anywhere from 28% to 65% (different models came up with varying degrees of impact) of the reduction in mortality by 2000 between 1975 and 2000.
The second paper, published in 2018 in the Journal of the American Medical Association, highlighted the differences in treatment responsiveness and survival outcomes among women with differing breast cancer subtypes from 2000 to 2012, pinpointing subgroups with poorer survival.
“We found that, while screening still had an important impact, most of the decline in annual deaths was due to improvements in treating early-stage breast cancer based on each cancer’s molecular profile,” Plevritis said.
The current study is the first to explicitly include patients with metastatic breast cancer in its models. The finding that 29% of the decrease in mortality is due to advances in treating metastatic breast cancer both surprised and gratified the researchers.
“Initially, we assumed that treatment of advanced disease was unlikely to make a significant contribution to the declines in mortality we documented in the previous two papers,” Caswell-Jin said. “But our treatments have improved, and it’s clear that they are having a significant impact on annual mortality.”
The CISNET researchers used four computer models to assess the SEER data from 1975 to 2019 — one developed at Stanford Medicine in the Plevritis Lab, one by researchers at the Dana-Farber Cancer Institute, one at MD Anderson Cancer Center, and another jointly developed by researchers at the University of Wisconsin and Harvard Medical School. The four models came up with remarkably similar estimates for the impact of each intervention: screening mammography, treatment of early-stage (stages 1, 2 or 3) breast cancer and treatment of metastatic breast cancer.
The models reproduced the decline in mortality in breast cancer known from SEER data, from 48 per 100 000 women dying of breast cancer each year in 1975 to 27 per 100,000 in 2019, a decrease of about 44%. The models arrived at a larger estimated reduction in mortality of about 58% because the incidence of breast cancer has risen during the same period and more women would have died had screening and treatments not improved.
The models concluded that about 47% of this reduction in mortality is the result of improved treatments for early-stage breast cancer, and about 25% is attributed to screening mammography. The remainder, or about 29%, is due to improvements in treating metastatic disease.
“Designing the new model, which had to account for individuals with non-metastatic cancer who underwent treatment but later progressed to metastatic cancer, and who may have been treated with multiple drugs over the course of their disease, was extremely complex,” Plevritis said. “It took about four years. But it was really satisfying when we were able to validate the model’s behaviour and see that all four models from different institutions, which used the new model inputs in different ways, delivered consistent findings. The models not only make sense, but also produce meaningful insights.”
The impact of treating metastatic disease is exemplified by the increases in median survival time after metastasis: Patients diagnosed in 2000 with metastatic disease lived an average of 1.9 years versus an average of 3.2 years for those diagnosed in 2019. Survival time varies by subgroup status, however. Patients with what are known as oestrogen receptor-positive and HER2 positive cancers saw an average increase in survival time of 2.5 years. Those with oestrogen receptor-positive and HER2-negative cancers lived an average of 1.6 years longer, but those with cancers that are oestrogen receptor-negative and HER2-negative lived about 0.5 years longer in 2019 than in 2000.
“It was meaningful as a breast oncologist to spend time with this history and see real progress over the past decades,” Caswell-Jin said. “There is much more work to be done; metastatic breast cancer isn’t yet curable. But it is rewarding to see that advances have made a difference in these numbers,” she added. “Our scientific and clinical work is helping our patients live longer, and I believe deaths from breast cancer will continue to steadily decline as innovation continues to grow.”
The cost of climate change may be six months off the average human lifespan, according to a study published January 18, 2024, in the open-access journal PLOS Climate by Amit Roy from Shahjalal University of Science and Technology and The New School for Social Research, US.
Temperature and rainfall – two telltale signals of climate change – cause myriad public health concerns, from the acute and direct (eg, natural disasters like flooding and heat waves) to the indirect yet equally devastating (eg, respiratory and mental illnesses). While impacts like these are observable and well documented, existing research has not established a direct link between climate change and life expectancy.
To clarify this relationship, the author evaluated average temperature, rainfall, and life expectancy data from 191 countries from 1940-2020, using GDP per capita to control for drastic differences between countries.
In addition to measuring the isolated impacts of temperature and rainfall, the author designed a first-of-its-kind composite climate change index, which combines the two variables to gauge the overarching severity of climate change.
Results indicate that in isolation, a global temperature increase of 1°C is associated with an average human life expectancy decrease of approximately 0.44 years, or about five months and one week. A 10-point increase in the composite climate change index – which accounts for both temperature and rainfall – is expected to decrease the average life expectancy by six months. Women and individuals in developing nations are disproportionately affected.
Beyond the results of this study, Dr Roy is hopeful that the composite climate change index will standardise the global conversation about climate change; become a usable metric for the nonscientific public; and encourage collaboration and even friendly competition among countries to combat the impacts of climate change.
Mitigating greenhouse gas emissions and adapting to a changing environment are of particular importance, the author says.
To complement this large-scale approach, the author suggests localised future studies that consider specific severe weather events (eg, wildfires, tsunamis, and floods), the impacts of which cannot be fully captured through analysing temperature and rainfall alone.
Dr Roy adds: “The global threat posed by climate change to the well-being of billions underscores the urgent need to address it as a public health crisis, as revealed by this study, emphasising that mitigation efforts to reduce greenhouse gas emissions and proactive initiatives are essential to safeguard life expectancy and protect the health of populations worldwide.”
IMPORTANT UPDATE: Following publication of the paper referenced below, concerns have been raised about the reliability of global mean annual temperature data that are discussed in the article and used in the study’s analyses. The source of these data is reported as [1] in the article’s Materials and methods section, and as [2] in the Fig 4 legend.
2. Akhtar R, Palagiano C. Climate change and air pollution: an introduction. Climate Change and Air Pollution: The Impact on Human Health in Developed and Developing Countries. 2018:3–8.
PLOS Climate is looking into the concerns that have been raised. Meanwhile, readers are advised to interpret this article’s results with caution. You may direct any specific questions to onepress@plos.org. We apologise sincerely for the inconvenience and thank you for your understanding.
