Tag: obesity

Categories : Genetics Metabolic DisordersTags :

Twin Study Reveals Epigenetic Signature for Obesity

On By ModernMedia
Photo by I Yunmai on Unsplash

A susceptibility to gain weight may be written into the epigenetic information of human cells, a Washington State University study indicates.

The proof-of-concept study with a set of 22 twins found an epigenetic signature in buccal cells appearing only for the twins who were obese compared to their thinner siblings. The findings could lead to the development of a simple cheek swab test for an obesity biomarker and enable earlier prevention, the researchers said.

“Obesity appears to be more complex than simple consumption of food. Our work indicates there’s a susceptibility for this disease and molecular markers that are changing for it,” said Michael Skinner, a WSU professor of biology and corresponding author of the study published in the journal Epigenetics.

The study focused on twins to help eliminate the role of genetics and instead focus on epigenetics, molecular processes which are separate from DNA but influence how genes are expressed. The fact that the epigenetic signature was found in cheek cells rather than fat cells also suggests that the obesity signature is likely found throughout the human system.

The signature’s systemic nature also suggests that something may have occurred early in one twin’s life that triggered obesity susceptibility, Skinner added. It’s also possible that it was inherited by one twin and not the other.

For this study, Skinner worked with lead author Glen Duncan, director of the Washington State Twin Registry based at WSU, to identify 22 twin pairs, both identical and fraternal, who were discordant for obesity: one sibling had a body mass index (BMI) of 30 or higher, the standard for obesity defined by the Centers of Disease Control and Prevention, while the other sibling was in the normal range of 25 and below.

The research team analysed cells from cheek swabs provided by the twins. In the cells from the twin siblings who were obese, they found similar epigenetic changes to DNA methylation regions, areas where molecular groups made of methane attach to DNA, regulating gene expression or turning genes on or off.

The study would need to be replicated with larger groups of people to develop a biomarker test for obesity, the authors said.

The goal would be able to identify people earlier in life before they become obese so health care providers might help create interventions such as lifestyle changes, medication or both, said Duncan.

“Ultimately we would like to have some kind of preventative measure instead of our usual approach which is treatment,” he said. “It’s a simple fact that it’s better to prevent a disease, then try to treat it after you have it.”

Source: Washington State University

Categories : Diet and Nutrition PaediatricsTags :

Study Classifies Four Eating Eating Behaviours of Children

On By ModernMedia
Photo by cottonbro studio

Children fall broadly into four eating categories, according to new research at Aston University, and parents feed their children differently depending on those categories.

The four categories identified by Dr Abigail Pickard and the team in the School of Psychology are ‘avid’, ‘happy’, ‘typical’, and ‘fussy’. The results, which showed specific temperaments and carer feeding patterns associated with overeating, are published in the journal Appetite.

In the UK, around a fifth of children are overweight or obese when they begin school, rising to around a third by the time they leave primary school at age 11. The team sought to identify eating behaviour patterns and how these are associated with temperament, feeding practices and food insecurity, as a way to predict which children are more at risk of becoming overweight.

Typical eaters made up 44% of the children in the study, while fussy eaters accounted for 16%. But of greatest interest to the team was that around one in five young children in the study were found to show “avid eating,” including greater enjoyment of food, faster eating speed, and weaker sensitivity to internal cues of ‘fullness’. The behaviours that distinguish children with avid eating from those who show ‘happy’ eating (17.7% of children in the study), who have similarly positive responses to food, are wanting to eat (or eating more) in response to the sight, smell or taste of palatable food, and a higher level of emotional overeating. In combination, these eating behaviours can lead to overeating and subsequent weight gain.

Dr Pickard and the team have also shown that there are significant differences in children’s temperament and caregivers’ feeding practices between each of the four eating behaviour patterns. Children with avid eating are more likely to be active and impulsive, and their caregivers are more likely to give them food to regulate their emotions or to restrict food for health reasons. Children with avid eating were also less food secure than children who showed happy or typical eating behaviours.

Principal investigator of the project, Professor Jackie Blissett, said: “Whilst feeding practices are key intervention targets to change children’s eating behaviour and child weight outcomes, there has been little evaluation of how feeding practices interact with children’s food approach behaviours to predict eating behaviour.”

She explained that despite the knowledge of the influence of feeding practices on children’s weight, current public health advice is generic and does not reflect variability in children’s appetites. Parents and caregivers can be left feeling frustrated when trying to manage their child’s food intake. By defining the four eating behaviour profiles, this research project, which is funded by the Economic and Social Research Council and co-developed by Professor Claire Farrow, Dr Clare Llewellyn, Dr Moritz Herle, Professor Emma Haycraft and Dr Helen Croker will make it easier to identify the best feeding practices for each eating pattern and provide tailored, effective advice for parents.

Dr Pickard said: “Parents can use this research to help them understand what type of eating pattern their child presents. Then based on the child’s eating profile the parent can adapt their feeding strategies to the child. For example, children in the avid eating profile may benefit more from covert restriction of food, i.e., not bringing snacks into the home or not having foods on display, to reduce the temptation to eat foods in the absence of hunger. Whereas, if a child shows fussy eating behaviour it would be more beneficial for the child to have a balanced and varied selection of foods on show to promote trying foods without pressure to eat.”

The team has planned further research investigating avid eating behaviour and will invite the caregivers and their children into the specialist eating behaviour lab at Aston University to get a better picture of what avid and typical eating behaviours look like in a real-life setting. All the findings will be integrated and the researchers will work with parents to develop feasible and helpful feeding guidelines to reduce children’s intake of palatable snack foods.

Source: Aston University

Categories : Gender GeneticsTags :

Researchers Identify Sex-specific Genes for Obesity

On By ModernMedia
Source: CC0

Researchers have added several genes, which appear to affect obesity risk in certain sexes and ages, to the list of genes which influence weight gain. The study, published in the journal Cell Genomics, may shed light on new biological pathways that underlie obesity and highlight how sex and age contribute to health and disease.

“There are a million and one reasons why we should be thinking about sex, age, and other specific mechanisms rather than just lumping everyone together and assuming that disease mechanism works the same way for everyone,” says senior author John Perry, a geneticist and professor at the University of Cambridge. “We’re not expecting people to have completely different biology, but you can imagine things like hormones and physiology can contribute to specific risks.”

To untangle sex’s role in obesity risk, the research team sequenced the exome (the protein-coding part of the genome) of 414 032 adults from the UK Biobank study. They looked at variants, or mutations, within genes associated with body mass index (BMI) in men and women, respectively. Five genes influencing BMI in women and two in men were identified.

Among them, faulty variants of three genes – DIDO1, PTPRG, and SLC12A5 – are linked to higher BMI in women, up to nearly 8 kg/m² more, while having no effect on men. Over 80% of the women with DIDO1 and SLC12A5 variants had BMI-indicated obesity. Those carrying DIDO1 variants had stronger associations with higher testosterone levels and increased waist-to-hip ratio, both risk indicators for obesity-related complications like diabetes and heart disease. Others with SLC12A5 variants had higher odds of having type 2 diabetes compared with non-carriers. These findings highlight previously unexplored genes that are implicated in the development of obesity in women but not men.

Perry and his colleague then repeated their method to look for age-specific factors by searching for gene variants associated with childhood body size based on participants’ recollections. They identified two genes, OBSCN and MADD, that were not previously linked to childhood body size and fat. While carriers of OBSCN variants had higher odds of having higher weight as a child, MADD variant carriers were associated with smaller body sizes. In addition, the genetic variants acting on MADD had no association with adult obesity risk, highlighting age-specific effects on body size.

“What’s quite surprising is that if you look at the function of some of these genes that we identified, several are clearly involved in DNA damage response and cell death,” says Perry. Obesity is a brain-related disorder, whereas biological and environmental factors act to influence appetite. “There’s currently no well-understood biological paradigm for how DNA damage response would influence body size. These findings have given us a signpost to suggest variation in this important biological process may play a role in the aetiology of obesity.”

Next, the research team hopes to replicate the study in a larger and more diverse population. They also plan to study the genes in animals to peer into their function and relationship with obesity.

“We’re at the very earliest stages of identifying interesting biology,” says Perry. “We hope the study can reveal new biological pathways that may one day pave the way to new drug discovery for obesity.”

Source: Science Daily

Categories : Genetics Metabolic DisordersTags :

Abdominal Fat Accumulation may not be as Great a Diabetes Risk as Previously Thought

On By ModernMedia
Photo by Andres Ayrton on Pexels

Conventional wisdom holds that abdominal fat accumulation increases the risk for type 2 diabetes. But surprising new findings from the University of Virginia School of Medicine suggest that naturally occurring genetic variations in our genes can lead some people to store fat at the waist but also protect them from diabetes.

The unexpected discovery, which is published in eLife, provides a more nuanced view of the role of obesity in diabetes and related health conditions. It also could pave the way for more personalised medicine, such as prioritising weight loss for patients whose genes put them at increased risk but place less emphasis on it for patients with protective gene variants, the researchers say.

“There is a growing body of evidence for metabolically healthy obesity. In this condition, people who would normally be at risk for cardiovascular diseases and diabetes because they are obese are actually protected from adverse effects of their obesity. In our study, we found a genetic link that may explain how this occurs in certain individuals,” said researcher Mete Civelek, PhD, of UVA’s Center for Public Health Genomics. “Understanding various forms of obesity is important to tailor treatments for individuals who are at high risk for adverse effects of obesity.”

As medicine grows more sophisticated, understanding the role of naturally occurring gene variations will play an important role in ensuring patients get the best, most tailored treatments. The new work by Civelek and his team, for example, indicates that variants can simultaneously predispose some people to store fat at the abdomen, thought to put them at increased risk for metabolic syndrome, while also protecting them from type 2 diabetes. (Metabolic syndrome raises the risk for diabetes, stroke and other serious health issues.)

One of the metrics doctors use to determine if a patient has metabolic syndrome is abdominal obesity. This is often calculated by comparing the patient’s waist and hip measurements. But Civelek’s research suggest that, for at least some patients, it may not be that simple, with doctors using genetic testing to guide patients to good health.

“We found that among the hundreds of regions in our genomes which increase our propensity to accumulate excess fat in our abdomens, there are five which have an unexpected role,” said Yonathan Aberra, the lead author of the study and a PhD candidate at UVA’s Department of Biomedical Engineering, a joint program of the School of Medicine and School of Engineering. “To our surprise, these five regions decrease an individual’s risk for type 2 diabetes.”

In addition to producing surprising findings, Civelek’s research provides important new tools for his fellow researchers seeking to understand the complexities of gene variations. The sophisticated approach Civelek and his collaborators developed to identify the relevant variants and their potential effects will be useful for future research into metabolic syndrome and other conditions.

The tools could also prove invaluable in the development of new and better treatments for metabolic syndrome, the scientists say.

“We now need to expand our studies in more women and people from different genetic ancestries to identify even more genes that underlie the metabolically health obesity phenomenon,” Civelek said. “We plan to build on our findings to perform more experiments to potentially identify a therapeutic target.”

Source: University of Virginia Health System

Categories : Metabolic Disorders PaediatricsTags :

Childhood TV Watching Linked to Metabolic Syndrome in Adulthood

On By ModernMedia
Photo by Victoria Akvarel on Pexels

A new study has added to the evidence that excessive TV watching as a child can lead to poor health in adulthood. The research, published this week in the journal Pediatrics, found that children who watched more television were more likely to develop metabolic syndrome as an adult.

Metabolic syndrome is a cluster of conditions including hypertension, hyperglycaemia, excess body fat, and abnormal cholesterol levels that lead to an increased risk of heart disease, diabetes and stroke.

Using data from 879 participants of the Dunedin study, researchers found those who watched more television between the ages of 5 and 15 were more likely to have these conditions at age 45.

Television viewing times were asked at ages 5, 7, 9, 11, 13 and 15. On average, they watched just over two hours per weekday.

“Those who watched the most had a higher risk of metabolic syndrome in adulthood,” says Professor Bob Hancox, who led the study.

“More childhood television viewing time was also associated with a higher risk of overweight and obesity and lower physical fitness.”

Boys watched slightly more television than girls and metabolic syndrome was more common in men, than women (34% and 20% respectively). The link between childhood television viewing time and adult metabolic syndrome was seen in both sexes however, and may even be stronger in women.

There was little evidence that watching less television as an adult reduced the association between childhood television viewing and adult health.

“While, like any observational study, researchers cannot prove that the association between television viewing at a young age directly causes adult metabolic syndrome, there are several plausible mechanisms by which longer television viewing times could lead to poorer long-term health.

“Television viewing has low energy expenditure and could displace physical activity and reduce sleep quality,” he says.

“Screentime may also promote higher energy intake, with children consuming more sugar-sweetened beverages and high-fat dietary products with fewer fruit and vegetables. These habits may persist into adulthood.”

The results are important because screen times have increased in recent years with new technologies.

“Children today have far more access to screen-based entertainment and spend much more time being sedentary. It is likely that this will have even more detrimental effects for adult health.

“These findings lend support to the World Health Organization recommendation that children and young teenagers should limit their recreational screen time.”

Source: University of Oregon

Categories : Diet and Nutrition GeneticsTags :

Obesity Genetic Risk Could be Curbed by Practising Restraint

On By ModernMedia
Photo by Jonathan Borba

Obesity risk genes make people feel hungrier and lose control over their eating, but practisng dietary restraint could counteract this, according to new research from University of Exeter. Published in the International Journal of Epidemiology, the study found that those with higher genetic risk of obesity can reduce the effects that are transmitted via hunger and uncontrolled eating by up to half through dietary restraint.

Lead author psychology PhD student, Shahina Begum said: “At a time when high calorie foods are aggressively marketed to us, it’s more important than ever to understand how genes influence BMI. We already know that these genes impact traits and behaviours such as hunger and emotional eating, but what makes this study different is that we tested the influence of two types of dietary restraint – rigid and flexible – on the effect of these behaviours. What we discovered for the first time was that increasing both types of restraint could potentially improve BMI in people genetically at risk; meaning that restraint-based interventions could be useful to target the problem.”

Genes linked to obesity increase BMI, with up to a quarter of this effect explained by increases in hunger and uncontrolled (including emotional) eating. There are over 900 genes that have so far been identified by researchers as being associated with BMI and several studies suggest these risk genes influence feelings of hunger and loss of control towards food.

This study examined 3780 adults aged between 22 and 92 years old from two UK cohorts: the Genetics of Appetite Study, and Avon Longitudinal Study of Parents and Children. Their weight and height were measured, and they provided a DNA sample via their blood to calculate an overall score for their genetic risk of obesity. They then completed questionnaires to measure 13 different eating behaviours, including disinhibition (a tendency to engage in binge or emotional eating) and over-eating due to hunger.

As expected, researchers found that a higher genetic risk score was associated with a higher BMI, partly due to increased disinhibition and hunger. However, results also found that those who had high levels of dietary restraint reduced those effects by almost half for disinhibition and a third for hunger, suggesting that restraint may counteract some of the effects of genetic risk.

There are different types of dietary restraint, including flexible strategies to rigid strategies, like calorie counting. The study tested the influence of both types of restraint for the first time and found both could potentially improve BMI in people genetically at risk.

Interventions to facilitate dietary restraint could include changing the food environment (by reducing the calorie content or portion size of food) or supporting individuals. To this end, members of the research team have developed a Food Trainer app (https://www.exeter.ac.uk/research/foodt/) to help achieve that. The app works as a game that trains people to repeatedly stop to high calorie food and research suggests this training may be particularly beneficial for those with a higher BMI.

Source: University of Exeter

Categories : Metabolic DisordersTags :

More Adolescents Are Underestimating Their Body Weight

On By ModernMedia
Photo by I Yunmai on Unsplash

A study involving more than 745 000 adolescents from 41 countries across Europe and North America identified an increase in the amount of teenagers who underestimate their body weight. Tracking data from 2002 to 2018, the findings, published in Child and Adolescent Obesity, also show fewer adolescents overestimating their weight.

The team of international experts, who carried out the research, warn these shifting trends in body weight perception could reduce the effectiveness of public health interventions aimed at weight reduction in young people.

“During this impressionable age, body weight perception may influence a young person’s lifestyle choices, such as the amount and types of food they eat and their exercise habits,” says lead author Doctor Anouk Geraets, from the Department of Social Sciences, at the University of Luxembourg.

“So it’s concerning that we’re seeing a trend where fewer adolescents perceive themselves as being overweight — as this could undermine ongoing efforts to tackle increasing levels of obesity in this age group. Young people who underestimate their weight and therefore do not consider themselves to be overweight may not feel they need to lose excess weight and, as a result, they may make unhealthy lifestyle choices.”

A person’s perception of their body weight may not accurately reflect their actual weight. A discrepancy in body weight perception (BWP) may either be an underestimation (where actual weight is higher than perceived weight) or an overestimation (where actual weight is lower than perceived weight).

In the present study, the researchers examined survey data from 746,121 11-, 13- and 15-year-olds from 41 countries collected at four-yearly intervals between 2002 and 2018 in the International Health Behavior in School-Aged Children (HBSC), a WHO collaborative study.

The team modeled trends in BWP among adolescents across different countries over time, making adjustments for age, gender, and family socioeconomic status. They found:

  • Underestimation of weight status increased, and overestimation of weight status decreased over time among both sexes, with stronger trends for girls.
  • Correct weight perception increased over time among girls, while it decreased among boys.
  • Changes in correct weight perception, underestimation and overestimation of weight status differed across different countries — but these changes could not be explained by an increase in country-level overweight/obesity prevalence.

The authors speculated that the observed differences between girls and boys in BWP may support the idea there are sex differences in body ideals — and that these body ideals have changed over time. Notably, the increased underestimation and decreased overestimation of weight status over time for girls may be explained by the emergence of an athletic and strong body, as a new contemporary body ideal for both sexes.

“This study has clinical and public health implications. The increase in correct weight perception and the decrease in overestimation may have a positive effect on unnecessary and unhealthy weight loss behaviors among adolescents, while the increase in underestimation might indicate the need for interventions to strengthen correct weight perception,” says lead author Doctor Anouk Geraets.

“More research is now needed to understand the factors underlying these time trends and to develop effective public health interventions.”

While the large number of participating countries is a strength of the present study, but as these only included countries in Europe, the USA and Canada, the results can’t be generalised to other regions. In addition, although steps were taken to adjust the models for certain potential confounding factors, several other factors – such as body image, dieting, changing eating patterns, or migration – may also have played a role in the observed trends over time.

Source: Taylor & Francis Group

Categories : Metabolic DisordersTags :

Even Modest Alcohol Intake Does not Reduce Diabetes, Obesity Risk

On By ModernMedia
Photo by Pavel Danilyuk on Pexels

Having only one or two alcoholic drinks per day does not protect against endocrine conditions such as obesity and type 2 diabetes, according to a new study published in the Journal of Clinical Endocrinology & Metabolism.

It is widely accepted that excessive alcohol consumption causes a wide range of health issues and is thus a major public health concern. Whether modest alcohol consumption has beneficial health effects remains controversial, however, due to the limited power of observational studies.

The researchers used mendelian randomisation (MR), which can help to mitigate biases due to confounding and reverse causation in observational studies, and evaluate the potential causal role of alcohol consumption.

“Some research has indicated that moderate drinkers may be less likely to develop obesity or diabetes compared to non-drinkers and heavy drinkers. However, our study shows that even light-to-moderate alcohol consumption (no more than one standard drink per day) does not protect against obesity and type 2 diabetes in the general population,” said Tianyuan Lu, PhD, from McGill University in Québec, Canada. “We confirmed that heavy drinking could lead to increased measures of obesity (body mass index, waist-to-hip ratio, fat mass, etc) as well as increased risk of type 2 diabetes.”

The researchers assessed self-reported alcohol intake data from 408 540 participants in the U.K. Biobank and found people who had more than 14 drinks per week had higher fat mass and a higher risk of obesity and type 2 diabetes. An extra drink per week was associated with an increased of 8% for diabetes risk and 10% for obesity risk.

These associations were stronger in women than in men. No data supported the association between moderate drinking and improved health outcomes in people drinking less than or equal to seven alcoholic beverages per week.

Source: The Endocrine Society

Categories : Mental Health Metabolic DisordersTags :

Obesity Raises Lifetime Risk of Mental Disorders

On By ModernMedia
Source: Pixabay CC0

Being obese significantly increases the chances of also developing mental disorders. This applies to all age groups, with women at higher risk than men for most diseases, as a recent study of the Complexity Science Hub and the Medical University of Vienna shows. The results were published in the specialist journal Translational Psychiatry.

“We analysed a population-wide national registry of inpatient hospitalisations in Austria from 1997 to 2014 in order to determine the relative risks of comorbidities in obesity and identify statistically significant sex differences,” explains Elma Dervic of the Complexity Science Hub. Consequently, it became evident that an obesity diagnosis significantly enhances the likelihood of a wide range of mental disorders across all age groups – including depression, nicotine addiction, psychosis, anxiety, eating and personality disorders. “From a clinical point of view, these results emphasise the need to raise awareness of psychiatric diagnoses in obese patients and, if necessary, to consult specialists at an early stage of diagnosis,” says Michael Leutner of the Medical University of Vienna.

First diagnosis: obesity

“In order to find out which illness typically appeared prior and subsequently to the obesity diagnosis, we had to develop a new method,” explains Dervic. This allowed the researchers to determine if there were trends and typical patterns in disease occurrence.

In case of all co-diagnoses, with the exception of the psychosis spectrum, obesity was in all likelihood the first diagnosis made prior to the manifestation of a psychiatric diagnosis. “Until now, physicians often considered psychopharmacological medications to cause the association between mental disorders and obesity as well as diabetes. This may be true for schizophrenia, where we see the opposite time order, but our data does not support this for depression or other psychiatric diagnoses,” explains Alexander Kautzky from Department of Psychiatry and Psychotherapy of the Medical University Vienna. However, whether obesity directly affects mental health or whether early stages of psychiatric disorders are inadequately recognised is not yet known.

Women more impacted

Surprisingly, the researchers found significant gender differences for most disorders — with women showing an increased risk for all disorders except schizophrenia and nicotine addiction.

While 16.66% of obese men also suffer from nicotine abuse disorder, this is only the case in up to 8.58% of obese women. The opposite is true for depression. The rate of diagnosed depressive episodes was almost three times higher in obese women (13.3% obese; 4.8% non-obese). Obese men were twice as likely to be affected (6.61% obese; 3.21% non-obese).

Early intervention is key

Since this study now also shows that obesity often precedes severe mental disorders, the findings reinforce its importance as a pleiotropic risk factor for health problems of all kinds. This is especially true for young age groups, where the risk is most pronounced, and for whom the researchers strongly recommend obesity screening.

Source: Complexity Science Hub Vienna

Categories : COVID VaccinesTags :

COVID Vaccination Protection Wanes Faster in People with Obesity

On By ModernMedia
Antibodies by Pikisuperstar on Freepix

According to new research from the Universities of Cambridge and Edinburgh, COVID vaccination protection in people with severe obesity wanes faster than in people of normal weight. The study suggests that people with obesity are likely to need more frequent booster doses to maintain their immunity.

Previous studies on COVID vaccines have suggested that antibody levels may be lower in vaccinated people who have obesity and that they may remain at higher risk of severe disease than vaccinated people with normal weight. The reasons for this have, however, remained unclear.

This study, published in the journal Nature Medicine, shows that the ability of antibodies to neutralise the virus (their ‘neutralisation capacity’) declines faster in vaccinated people who have obesity. The findings have important implications for vaccine prioritisation policies around the world.

During the pandemic, people with obesity were more likely to be hospitalised, require ventilators and to die from COVID. In this study, supported by the NIHR Bioresource and funded by UKRI, the researchers set out to investigate how far two of the most extensively used vaccines protect people with obesity compared to those with a normal weight, over time.

A team from the University of Edinburgh looked at real-time data tracking the health of 3.5 million people in the Scottish population as part of the EAVE II study. They looked at hospitalisation and mortality from COVID in adults who received two doses of COVID vaccine (either Pfizer-BioNTech or AstraZeneca).

They found that people with severe obesity (a BMI > 40kg/m2) had a 76% higher risk of severe COVID outcomes, compared to those with a normal BMI. A modest increase in risk was also seen in people with obesity (30-39.9kg/m2), which affects a quarter of the UK population, and those who were underweight. ‘Break-through infections’ after the second vaccine dose also led to hospitalisation and death sooner (from 10 weeks) among people with severe obesity, and among people with obesity (after 15 weeks), than among individuals with normal weight (after 20 weeks).

University of Edinburg leader Prof Sir Aziz Sheikh said: “Our findings demonstrate that protection gained through COVID vaccination drops off faster for people with severe obesity than those with a normal body mass index. Using large-scale data assets such as the EAVE II Platform in Scotland have enabled us to generate important and timely insights that enable improvements to the delivery of COVID vaccine schedules in a post-pandemic UK.”

The University of Cambridge team studied people with severe obesity attending the Obesity clinic at Addenbrooke’s Hospital in Cambridge, and compared the number and function of immune cells in their blood to those of people of normal weight.

They studied people six months after their second vaccine dose and then looked at the response to a third ‘booster’ vaccine dose over time. The Cambridge researchers found that six months after a second vaccine dose, people with severe obesity had similar levels of antibodies to the COVID virus as those with a normal weight – but those antibodies were less effecctive.

The antibodies’ neutralisation capacity was reduced in 55% of individuals with severe obesity were found to have unquantifiable or undetectable ‘neutralising capacity’ compared to 12% of people with normal BMI.

“This study further emphasises that obesity alters the vaccine response and also impacts on the risk of infection,” said first author Dr Agatha van der Klaauw. “We urgently need to understand how to restore immune function and minimise these health risks.”

The researchers found that antibodies produced by people with severe obesity were less effective at neutralising the SARS-CoV-2 virus, potentially because the antibodies were not able to bind to the virus with the same strength.

When given a third (booster) dose of a COVID vaccine, neutralisation capacity was restored in both the normal weight and severely obese groups. But the researchers found that immunity again declined more rapidly in people with severe obesity, putting them at greater risk of infection with time.