Category: Science News

{By adopting a walking routine and other moderate physical activities, older adults can recover from a major disability more quickly, and maintain their independence over time, according to a new Yale-led study.}

The study results, published Sept. 26 by the Annals of Internal Medicine, are drawn from the Lifestyle Interventions and Independence for Elders (LIFE) Study — the largest and longest trial of physical activity in older people.

In the randomized trial, the research team compared the effects of a structured physical activity program to those of a health education program on more than 1,600 adults between the ages of 70 and 89. The study participants were not disabled but were sedentary and had some physical limitations. The activity program consisted mainly of walking, in addition to strength, flexibility, and balance training exercises.

Over 3½ years, participants were assessed for major mobility disability, which was defined as the inability to walk a quarter mile. Older adults need to be able to walk this distance to participate in many activities and maintain their independence, the researchers said.

The research team found that compared to the health education program, the physical activity program reduced the total time that older adults suffered from major disability by 25%. The participants were less likely to experience disability in the first place, more likely to recover if they did suffer a disability, and less likely to have a subsequent episode, said the researchers.

“Our report strengthens the evidence supporting the benefit and long-term value of physical activity in promoting independent mobility among a growing population of vulnerable older persons,” said Dr. Thomas Gill, first author and professor of geriatrics.

The findings bolster previously reported results from the LIFE Study, which demonstrated that the structured physical activity program reduced the risk of experiencing a first episode of major mobility disability. The latest results also inform a growing body of research showing that older adults often transition between states of independence and disability over time.

“Interventions to promote independent mobility should focus not only on preventing the initial occurrence of disability, but also on restoring and maintaining independent mobility in older persons who become disabled,” Gill noted.

{The baby boy was born five months ago in Mexico to Jordanian parents, and is healthy and doing well, said the report in New Scientist magazine, described as an “exclusive”}

The world’s first baby has been born thanks to a controversial new technique employed by US scientists to include DNA from three parents in the embryo, said a report Tuesday.

The baby boy was born five months ago in Mexico to Jordanian parents, and is healthy and doing well, said the report in New Scientist magazine, described as an “exclusive.”

The boy’s mother carried genes for a disorder known as Leigh Syndrome, a fatal nervous system disorder which she had passed on to her two previous children who both died of the disease.

She had also suffered four miscarriages.

The woman, whose identity was withheld by New Scientist, and her husband sought the help of John Zhang, a doctor from the New Hope Fertility Center in New York City to have a baby that would be genetically related to them but would not carry the inherited disease.

The United States has not approved any three-parent method for fertility purposes, so Zhang went to Mexico where he was quoted by New Scientist as saying “there are no rules.”

One method that has been approved in the United Kingdom, called pronuclear transfer, was deemed unacceptable to the couple because it would involve the destruction of two embryos, said the report.

Since the mother carried the genes for the disease in her mitochondria, or DNA that is passed down from the maternal side, Zhang used her nuclear DNA and combined it with mitochondria from an egg donor, in a technique known as spindle nuclear transfer.

“He removed the nucleus from one of the mother’s eggs and inserted it into a donor egg that had had its own nucleus removed,” said the report.

“The resulting egg –- with nuclear DNA from the mother and mitochondrial DNA from a donor -– was then fertilized with the father’s sperm.”

– Presentation next month -Zhang and his team are expected to describe their method at the American Society for Reproductive Medicine meeting in Salt Lake City, Utah, next month.

An abstract describing the research has been published in the journal Fertility and Sterility, but outside experts said much more remains to be understood about the research.

“As this technology is controversial and a world first, I think the investigators should have submitted a manuscript for full peer review instead of announcing these outcomes in this manner,” said Justin St John, professor and Director of the Centre for Genetic Diseases at Monash University.

Attempts began in the 1990s to create a baby by injecting mitochondrial DNA from a donor into the mother’s egg, and adding sperm from her partner.

“Some of the babies went on to develop genetic disorders, and the technique was banned,” said the New Scientist report.

{The hair-of-the-dog-that-bit-you is a time-honored allergy remedy for a good reason: It works.}

But how it works has not been well understood.

Now a research team led by Duke Health, using mice as the models, has described the cellular processes that occur during “rush desensitization.” The approach involves giving a small dose of the allergy trigger — peanuts or bee poison or even chemotherapy — to the susceptible patient in small, yet increasing doses over a short period.

“We have known for at least 100 years that the approach is effective,” said Soman Abraham, Ph.D, senior author of a study published online Sept. 26 in the Journal of Clinical Investigation. Abraham is professor in the departments of Pathology, Immunology, and Microbiology and Molecular Genetics at Duke University School of Medicine and professor in the Program of Emerging Infectious Diseases at Duke-National University Singapore Medical School. “People who have terrible, even life-threatening reactions to certain antigens can then tolerate an exposure — if just for a short period of time.”

Understanding how the process works could lead to new and better therapies for managing allergies to foods, dust, pollen, drugs and insect bites that cause serious and even fatal reactions for millions of people annually.

Abraham and colleagues employed different experiments to track the cellular events during allergic reactions and after rush desensitization. The team included A. Wesley Burks, M.D., who, before he left Duke for the University of North Carolina at Chapel Hill, pioneered a peanut allergy approach for children that relied on rush desensitization principals.

Allergy symptoms arise from a process that starts in the immune system’s mast cells, which are white blood cells that harbor tiny containers called granules filled chemicals involved in the inflammatory process such as histamines and heparins.

When a person is exposed to an allergen such as pollen for the first time, the body makes an antibody known as immunoglobulin E, or IgE, which is capable of binding to the allergen whenever another exposure occurs.

Once produced, these IgE antibodies collect in large numbers on the surface of mast cells. During subsequent exposures, the allergen is promptly recognized by IgE, which binds to it and immobilizes it on the mast cell. That process initiates a signal that triggers expulsion of the granules from the mast cell, releasing the inflammatory chemicals.

The result is allergy symptoms such as sneezing, wheezing, itching and swelling. In severe cases, when mast cells lining blood vessels release their inflammatory contents throughout the body, the reaction can be life-threatening.

It’s long been understood that rush desensitization therapy somehow disrupts the mast cells through the repeated exposure of allergens over several hours or days.

Abraham and colleagues found that the disruption occurs inside the mast cells, among tiny filaments called actin that line the inner envelop of the cell. When confronted with an allergen, the actin breaks down and rushes to the center of the cell, creating the conditions necessary for the eruption of the granules.

When tiny doses of allergen are administered during rush desensitization, however, the actin are fooled into disassembling, and prematurely move to the center of the cell. The misplacement of the cellular actin, however, does not initiate expulsion of the granules and the inflammatory chemicals. Even with repeated and escalating exposures, the cascade of events is avoided and there is no allergic reaction.

“Having figured out the mechanism, we should now be able to find new drugs that can target the actin and prolong the desensitization,” said lead author W.X. Gladys Ang, a graduate student in the Department of Molecular Genetics & Microbiology at Duke. “This will allow for recovery to be slower, enabling people to be tolerant of allergens for longer periods.”

{New research from the University of East Anglia (UEA) argues that children’s ability to make moral judgements has often been substantially underestimated.}

When making moral judgements, adults tend to focus on people’s intentions rather than on the outcomes of their actions: hurting someone intentionally is much worse than hurting them accidentally. However, the prevailing view in developmental psychology is that younger children’s moral judgements are mainly based on the outcomes of actions, rather than the intentions of those involved.

Despite decades of research there is still disagreement about whether this claim is correct. To address this, the UEA researchers looked at the reasons for the findings of two of the most influential and frequently cited studies in this area, both of which provide strong evidence that young children’s moral judgements are mainly outcome-based.

These studies also tested adults, something which enables researchers to establish the mature response against which children at various ages can be compared. Many of them also made outcome-based judgements, which prompted the UEA researchers to question the methods used.

The team, led by Dr Gavin Nobes of UEA’s School of Psychology, replicated the studies — published in 1996 and 2001 — and examined the effects of rephrasing one of the questions. Whereas in the original studies children were asked whether the action was good or bad, the new question asked about the person who acted.

As in previous research on whether moral judgements are based on intention or outcome, children were asked about pairs of stories in which accidents took place. In one the intention was good and the outcome bad, and in the other the intention was bad but the outcome good.

In the UEA study, when the original question was asked the findings were very similar to the previous studies. That is, children’s and adults’ judgements were primarily outcome-based: regardless of intention, they judged accidents with good outcomes to be good, and accidents with bad outcomes to be bad.

However, when the question was rephrased, the 4- to 5-year-olds’ judgements were equally influenced by intention and outcome, and from 5 to 6 years they were mainly intention-based. The older children’s and adults’ judgments were essentially reversed, from almost exclusively outcome-based in response to the original question, to almost exclusively intention-based when the rephrased question was asked.

Dr Nobes, a senior lecturer in psychology, said: “This area of research is about a fundamental aspect of morality. For most adults, if someone does something bad deliberately, they are worse than if they did it accidentally.

“The long-held claim has been that young children judge according to the outcome of an event, rather than according to the person’s intention. If that is the case, then children’s moral judgments are fundamentally different from adults’.

“However, our findings indicate that for methodological reasons, children’s ability to make similar intention-based judgements has often been substantially underestimated. We show that they can be remarkably adult-like in their thinking. The implication is that even young children, from around the age of 4, can make intention-based moral judgements, just like adults.”

“If adults get a judgement wrong then a 5-year-old child is bound to get it wrong too, so we looked at whether the authors of the original studies asked the appropriate, relevant question,” said Dr Nobes. “It appears that they did not, yet the robustness of the original findings has rarely, if ever, been questioned. Neither have these studies been replicated, nor alternative explanations investigated. This is a concern when research findings are subsequently used by researchers and others to inform their work with children.”

The UEA study involved 138 children aged 4- to 8-years-old and 31 adults. They were told and questioned about four stories involving accidental harms (positive intention, negative outcome) or attempted harms (negative intention, positive outcome). The stories, pictures and questions were identical to those of the original studies, except that each participant was asked the original acceptability question about two of the stories, and a rephrased acceptability question about the other two.

Examples of the acceptability questions asked are:

Original: “Is it okay for Ethan to give Chris a big spider? How good/bad is it to give Chris a big spider? Is it really, really good/bad or just a little good/bad, or just okay?

Rephrased: “Is Ethan good, bad or just okay? How good/bad? Is he really, really good/bad, just a little good/bad, or just okay?”

Dr Nobes said: “Our findings could hardly have been clearer. The main implication is that, when the rephrased, person-focused acceptability question was asked, there was no evidence at any age to support the claim that children’s judgements are primarily outcome-based.

“It appears that the majority of participants both in our study and in the original studies interpreted the original acceptability question to be solely about whether the outcome was good or bad, and so did not take the person’s intention, and therefore culpability, into account.

“The wrong question was asked in the original studies. We know the replication worked because when we asked the same questions we got the same or very similar results. We made a minor change but the results are dramatically different, and the only possible explanation is the rewording of the question.”

{It has long puzzled scientists why, after 3 billion years of nothing more complex than algae, complex animals suddenly started to appear on Earth. Now, a team of researchers has put forward some of the strongest evidence yet to support the hypothesis that high levels of oxygen in the oceans were crucial for the emergence of skeletal animals 550 million years ago.}

The new study is the first to distinguish between bodies of water with low and high levels of oxygen. It shows that poorly oxygenated waters did not support the complex life that evolved immediately prior to the Cambrian period, suggesting the presence of oxygen was a key factor in the appearance of these animals.

The research, based on fieldwork carried out in the Nama Group in Namibia, is published in the journal Nature Communications.

Lead author Dr Rosalie Tostevin completed the study analyses as part of her PhD with UCL Earth Sciences, and is now in the Department of Earth Sciences at Oxford University. She said: ‘The question of why it took so long for complex animal life to appear on Earth has puzzled scientists for a long time. One argument has been that evolution simply doesn’t happen very quickly, but another popular hypothesis suggests that a rise in the level of oxygen in the oceans gave simple life-forms the fuel they needed to evolve skeletons, mobility and other typical features of modern animals.

‘Although there is geochemical evidence for a rise in oxygen in the oceans around the time of the appearance of more complex animals, it has been really difficult to prove a causal link. By teasing apart waters with high and low levels of oxygen, and demonstrating that early skeletal animals were restricted to well-oxygenated waters, we have provided strong evidence that the availability of oxygen was a key requirement for the development of these animals. However, these well-oxygenated environments may have been in short supply, limiting habitat space in the ocean for the earliest animals.’

The team, which included other geochemists, palaeoecologists and geologists from UCL and the universities of Edinburgh, Leeds and Cambridge, as well as the Geological Survey of Namibia, analysed the chemical elemental composition of rock samples from the ancient seafloor in the Nama Group – a group of extremely well-preserved rocks in Namibia that are abundant with fossils of early Cloudina, Namacalathus and Namapoikia animals.

The researchers found that levels of elements such as cerium and iron detected in the rocks showed that low-oxygen conditions occurred between well-oxygenated surface waters and fully ‘anoxic’ deep waters. Although abundant in well-oxygenated environments, early skeletal animals did not occupy oxygen-impoverished regions of the shelf, demonstrating that oxygen availability (probably >10 micromolar) was a key requirement for the development of early animal-based ecosystems.

Professor Graham Shields-Zhou (UCL Earth Sciences), one of the co-authors and Dr Tostevin’s PhD supervisor, said: ‘We honed in on the last 10 million years of the Proterozoic Eon as the interval of Earth’s history when today’s major animal groups first grew shells and churned up the sediment, and found that oxygen levels were important to the relationship between environmental conditions and the early development of animals.’

{The copper used to make Ötzi’s axe blade did not come from the Alpine region as had previously been supposed, but from ore mined in southern Tuscany. Ötzi was probably not involved in working the metal himself, as the high levels of arsenic and copper found in his hair had, until now, led us to assume. }

His murder over 5,000 years ago seems to have been brought about due to a personal conflict a few days before his demise, and the man from the ice, despite his normal weight and active life-style, suffered from extensive vascular calcification. Scientists from all over the world presented these and other new insights, at the recent International Mummy Congress in Bozen-Bolzano. To celebrate the 25th anniversary of Ötzi’s discovery, the three days of the Congress, from 19th to 21st September, are all dedicated to the man from the ice.

Since the man from the ice came on the scene on 19th September 1991, he has not ceased to fascinate scientists from all over the world. No corpse has been more thoroughly investigated. “In terms of his significance for science, Ötzi is not simply an isolated mummy discovery. He could be seen as a typical European from earlier times and is precious for this reason alone,” explained the anthropologist Albert Zink from EURAC Research, the scientific leader of the congress.

“Ötzi is so well preserved as a glacier mummy and through this alone, he serves us researchers as a model for developing scientific methods which can then be used on other mummies,” said Zink. “What concerns us most these days is to know who the man from the ice was, what role he played in society and what happened to him in the last days of his life. Sophisticated procedures, now available to scientists, are continually supplying us with new evidence,” said Angelika Fleckinger, Director of the South Tyrol Museum of Archaeology which helped to organise the Congress.

{{Links to Central Italy}}

One surprising new fact has been unearthed which concerns the most extraordinary item amongst Ötzi’s equipment — the valuable copper axe. In contrast to what had previously been presumed, the copper used in the blade does not derive from the Alpine region (researchers had suggested East or North Tyrol as the most likely provenance) but from Central Italy. Professor Gilberto Artioli’s archaeometallurgy research group at the University of Padua has discovered that the metal had been obtained from ore mined in South Tuscany. In order to determine its origin, Italian scientists took a tiny sample from the blade and compared the proportion of lead isotope — a kind of “finger print” of the ore deposits which remains unchanged in any objects subsequently made from the ore — with the corresponding data from numerous mineral deposits in Europe and the entire Mediterranean region.

The result pointed unequivocally to South Tuscany. “No one was prepared for this finding. We will commission further analyses in order to double-check these first results” stressed Angelika Fleckinger. If the original results are confirmed, this new evidence will give researchers some interesting food for thought. Was Ötzi as a trader travelling possibly as far as the area around today’s Florence? What was the nature of the trading and cultural links with the south in those days? Did the exchange of goods also involve movements of the population? That is to say, did people from the south venture into the Alpine region and vice versa? “This is a particularly exciting insight especially with respect to questions about population development,” explained Albert Zink.

{{Was he or was he not involved in smelting copper?}}

Another question long debated amongst the scientific community, is whether Ötzi was perhaps involved himself in the process of copper smelting. Scientists have advocated this thesis because raised arsenic and copper levels have been measured in the mummy’s hair, a fact which might possibly be explained, for example, by breathing in the smoke which is released when melting and pouring metal. Geochemist Wolfgang Müller of Royal Holloway, University of London, who had already used isotope analysis to establish Ötzi’s South Tyrol origins, has now turned to this question once more.

Using highly developed methods of analysis such as laser mass spectrometry and speciation analysis, Müller’s team examined not just hairs but also samples from Ötzi’s nails, skin and organs for possible heavy metal contamination. His, so far still provisional, findings suggest that the hypothesis that Ötzi was involved in processing metal was premature. Müller did indeed find slightly raised arsenic values in the nail sample, but not in other tissue samples. Raised copper levels were only present at the extremities and this correlates with other change indicators, and thus it is doubtful if one can establish a heavy metal contamination for Ötzi’s actual life time: raised values might also be due to environmental influences over the 5,000 years since his death.

{{Radiological investigations with the latest CT equipment}}

A new computer tomography (CT) scan of the man from the ice was undertaken by radiologists Paul Gostner and Patrizia Pernter in January 2013 in the Department of Radiology of Bozen-Bolzano Hospital. To do this they used a CT-scanner of the latest generation which, thanks to its large opening, allowed the doctors to run Ötzi rapidly through the machine from head to toe despite the way his arm is angled. In addition to the vascular calcification in the arteries of his stomach and legs which had already been known about, the superior image allowed doctors to spot three small areas of calcification near to the outflow tracts of the heart which had hitherto escaped their notice. This substantiates the earlier finding made by molecular biologists in EURAC that Ötzi had a strong genetic predisposition to cardiovascular diseases and that this was probably also the main reason for his general arteriosclerosis.

{{Investigations of a “profiler”}}

Ötzi was murdered. The arrow head discovered in 2001 in his left shoulder suggests this. But what were the circumstances surrounding the crime? In 2014 the South Tyrol Museum of Archaeology commissioned Chief Inspector Alexander Horn of the Munich Criminal Investigation Department to investigate the “Ötzi Murder Case” using the latest criminological methods. Horn interrogated various “acquaintances” of the murder victim such as archaeologists from the museum who had been looking after Ötzi for years, or experts from forensic medicine, radiology and anthropology. Members of the project team also took part in an on-site inspection of the location in Schnals where the body was found.

The results of this investigation were that Ötzi probably did not feel threatened shortly before his murder, because the situation at the Tisenjoch location where he was found indicates that he had been resting while enjoying a hearty meal. In the days prior to the murder he had incurred an injury to his right hand, probably as a result of defensive action during the course of a physical altercation. No further injuries could be found, and this might serve to indicate that he had not been defeated in this particular conflict. The arrow shot, which was probably fatal, seems to have been launched from a great distance and took the victim by surprise, from which we may infer that it was an act of treachery.

Further medical findings suggest that the victim fell and that the perpetrator used no further violence. The perpetrator probably did not wish to risk a physical altercation, but instead chose a long distance attack to kill the man from the ice. As valuable objects such as the copper axe remained at the crime scene, theft can be excluded as the motive. The reason for the offence is more likely to be found in some sort of personal conflict situation, in a previous hostile encounter — “a behavioural pattern which is prevalent even today in the bulk of murder crimes,” as Alexander Horn explained.

{Study of rare genetic disorder reveals importance of touch and body awareness.}

With the help of two young patients with a unique neurological disorder, an initial study by scientists at the National Institutes of Health suggests that a gene called PIEZO2 controls specific aspects of human touch and proprioception, a “sixth sense” describing awareness of one’s body in space. Mutations in the gene caused the two to have movement and balance problems and the loss of some forms of touch. Despite their difficulties, they both appeared to cope with these challenges by relying heavily on vision and other senses.

“Our study highlights the critical importance of PIEZO2 and the senses it controls in our daily lives,” said Carsten G. Bönnemann, M.D., senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and a co-leader of the study published in the New England Journal of Medicine. “The results establish that PIEZO2 is a touch and proprioception gene in humans. Understanding its role in these senses may provide clues to a variety of neurological disorders.”

Dr. Bönnemann’s team uses cutting edge genetic techniques to help diagnose children around the world who have disorders that are difficult to characterize. The two patients in this study are unrelated, one nine and the other 19 years old. They have difficulties walking; hip, finger and foot deformities; and abnormally curved spines diagnosed as progressive scoliosis.

Working with the laboratory of Alexander T. Chesler, Ph.D., investigator at NIH’s National Center for Complementary and Integrative Health (NCCIH), the researchers discovered that the patients have mutations in the PIEZO2 gene that appear to block the normal production or activity of Piezo2 proteins in their cells. Piezo2 is what scientists call a mechanosensitive protein because it generates electrical nerve signals in response to changes in cell shape, such as when skin cells and neurons of the hand are pressed against a table. Studies in mice suggest that Piezo2 is found in the neurons that control touch and proprioception.

“As someone who studies Piezo2 in mice, working with these patients was humbling,” said Dr. Chesler. “Our results suggest they are touch-blind. The patient’s version of Piezo2 may not work, so their neurons cannot detect touch or limb movements.”

Further examinations at the NIH Clinical Center suggested the young patients lack body awareness. Blindfolding them made walking extremely difficult, causing them to stagger and stumble from side to side while assistants prevented them from falling. When the researchers compared the two patients with unaffected volunteers, they found that blindfolding the young patients made it harder for them to reliably reach for an object in front of their faces than it was for the volunteers. Without looking, the patients could not guess the direction their joints were being moved as well as the control subjects could.

The patients were also less sensitive to certain forms of touch. They could not feel vibrations from a buzzing tuning fork as well as the control subjects could. Nor could they tell the difference between one or two small ends of a caliper pressed firmly against their palms. Brain scans of one patient showed no response when the palm of her hand was brushed.

Nevertheless, the patients could feel other forms of touch. Stroking or brushing hairy skin is normally perceived as pleasant. Although they both felt the brushing of hairy skin, one claimed it felt prickly instead of the pleasant sensation reported by unaffected volunteers. Brain scans showed different activity patterns in response to brushing between unaffected volunteers and the patient who felt prickliness.

Despite these differences, the patients’ nervous systems appeared to be developing normally. They were able to feel pain, itch, and temperature normally; the nerves in their limbs conducted electricity rapidly; and their brains and cognitive abilities were similar to the control subjects of their age.

“What’s remarkable about these patients is how much their nervous systems compensate for their lack of touch and body awareness,” said Dr. Bönnemann. “It suggests the nervous system may have several alternate pathways that we can tap into when designing new therapies.”

Previous studies found that mutations in PIEZO2 may have various effects on the Piezo2 protein that may result in genetic musculoskeletal disorders, including distal arthrogryposis type 5, Gordon Syndrome, and Marden-Walker Syndrome. Drs. Bönnemann and Chesler concluded that the scoliosis and joint problems of the patients in this study suggest that Piezo2 is either directly required for the normal growth and alignment of the skeletal system or that touch and proprioception indirectly guide skeletal development.

“Our study demonstrates that bench and bedside research are connected by a two-way street,” said Dr. Chesler. “Results from basic laboratory research guided our examination of the children. Now we can take that knowledge back to the lab and use it to design future experiments investigating the role of PIEZO2 in nervous system and musculoskeletal development.”

This work was supported by the NCCIH and NINDS intramural research programs.

{An international research team co-led from the Children’s Hospital of Eastern Ontario (CHEO) and the University of North Dakota studied the aerobic fitness levels of children and youth across 50 countries.The results are available now in the British Journal of Sports Medicine.}

“Kids who are aerobically fit tend to be healthy; and healthy kids are apt to be healthy adults. So studying aerobic fitness in the early years is very insightful to overall population health,” said Justin Lang, lead author, Healthy Active Living and Obesity (HALO) research group, CHEO and PhD student, University of Ottawa. “It’s important to know how kids in Canada or America fare on the world stage, for example, because we can always learn from other countries with fitter kids.”

The study involved analyzing 20-meter shuttle data, also called the beep test, from 1.1 million kids aged 9 to 17 years old from 50 countries. The beep test is the most popular field-based test of aerobic fitness levels of children and youth. It is also standardized and commonly used around the world.

“If all the kids in the world were to line up for a race, the average American child would finish at the foot of the field,” said Dr. Grant Tomkinson, senior author, associate professor, University of North Dakota. “Canada, on the other hand, fared moderately well placing just above middle of the pack. This study is the largest of its kind so it’s exciting to have this evidence at hand.”

Another key finding of this study is that income inequality — the gap between rich and poor as measured by the Gini Index — is strongly correlated with aerobic fitness. Children and youth from countries with a small gap between rich and poor appear to have better fitness.

Study collaborators include co-authors from the University of Montreal and University of South Australia.

Ranking highlights:

* Top 5 fittest countries:

Tanzania
Iceland
Estonia
Norway
Japan
* Canada placed 19 out of 50

* America placed 47 out of 50

* The least fit is Mexico

{You might be able to blame your genes for weighing more and increasing your risk of obesity, but you can no longer blame your genes for failing to lose weight, a comprehensive study has found.}

Carriers of the FTO gene are known to be on average 3 kilos (6.6lbs) heavier and 70% more likely to be obese. However, researchers at Newcastle University, publishing in The BMJ today, report that in a review of eight studies involving over 9,000 people, carrying this gene did not prevent them losing weight.

John Mathers, Professor of Human Nutrition at Newcastle University, who led the study, said: “You can no longer blame your genes. Our study shows that improving your diet and being more physically active will help you lose weight, regardless of your genetic makeup.”

{{Getting the weight off}}

Obesity is a major health problem and, in the UK, more than 25% of adults are obese. For some people, carrying the risk variant of the FTO gene can lead to them being heavier and increasing their risk of obesity. The FTO gene has been shown to have the biggest effect in this area.

In a major collaborative systematic review and meta-analysis, the international team used individual data from 9,563 adults who were enrolled in randomised controlled weight loss trials around the world to find out whether carrying the risk version of the FTO gene affects how much weight people lose.

They found that carrying the risk version of the FTO gene had no effect on weight loss as Professor Mathers explains: “We were excited to find that people with the risk version of FTO respond just as well to weight loss interventions as everyone else.

“This is important news for people trying to lose weight as it means that diet, physical activity or drug-based weight loss plans will work just as well in those who carry the risk version of FTO.

“For public health professionals, it means that the adverse effects of the FTO genotype on weight gain are not an impediment to weight loss interventions.”

FTO gene carriers

Importantly, the team found that the response to weight loss interventions for people carrying the risk variant of the FTO gene was similar for men and women, younger and older and people of different ethnicities. However, most people in the studies were Caucasians with smaller numbers of those from Black/ African American and Hispanic backgrounds. The team say future research should explore effects of FTO on weight loss in other ethnic groups. In addition, the effects of other obesity-related genes on weight loss remain to be investigated.

In a linked editorial in The BMJ, Dr Alison Tedstone, chief nutritionist at Public Health England, says the causes of the obesity epidemic are multiple and complex, but current evidence suggests they have little to do with gene profiles.

She argues that, if we are to turn back the tide of obesity, a focus on personalised interventions based on the genome “may not pay off, at least in the short term.” Instead, she says “a rebalancing of research towards whole systems approaches including environmental drivers may be of greater benefit to the population in the long term.”