Can your blood type affect your memory in later years?

People with blood type AB may be more likely to develop memory loss in later years than people with other blood types, according to a study. AB is the least common blood type, found in about 4 percent of the U.S. population. The study found that people with AB blood were 82 percent more likely to develop the thinking and memory problems that can lead to dementia than people with other blood types.
New research suggests that people with blood type AB may be more likely to develop memory loss in later years than people with other blood types.
Credit: © Africa Studio / Fotolia

People with blood type AB may be more likely to develop memory loss in later years than people with other blood types, according to a study published in the September 10, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology.

AB is the least common blood type, found in about 4 percent of the U.S. population. The study found that people with AB blood were 82 percent more likely to develop the thinking and memory problems that can lead to dementia than people with other blood types. Previous studies have shown that people with type O blood have a lower risk of heart disease and stroke, factors that can increase the risk of memory loss and dementia.

The study was part of a larger study (the REasons for Geographic And Racial Differences in Stroke, or REGARDS Study) of more than 30,000 people followed for an average of 3.4 years. In those who had no memory or thinking problems at the beginning, the study identified 495 participants who developed thinking and memory problems, or cognitive impairment, during the study. They were compared to 587 people with no cognitive problems.

People with AB blood type made up 6 percent of the group who developed cognitive impairment, which is higher than the 4 percent found in the population.

“Our study looks at blood type and risk of cognitive impairment, but several studies have shown that factors such as high blood pressure, high cholesterol and diabetes increase the risk of cognitive impairment and dementia,” said study author Mary Cushman, MD, MSc, of the University of Vermont College of Medicine in Burlington. “Blood type is also related to other vascular conditions like stroke, so the findings highlight the connections between vascular issues and brain health. More research is needed to confirm these results.”

Researchers also looked at blood levels of factor VIII, a protein that helps blood to clot. High levels of factor VIII are related to higher risk of cognitive impairment and dementia. People in this study with higher levels of factor VIII were 24 percent more likely to develop thinking and memory problems than people with lower levels of the protein. People with AB blood had a higher average level of factor VIII than people with other blood types.

Story Source:

The above story is based on materials provided by American Academy of Neurology (AAN). Note: Materials may be edited for content and length.

Journal Reference:

  1. Kristine S. Alexander, Neil A. Zakai, Sarah Gillett, Leslie A. Mcclure, Virginia Wadley, Fred Unverzagt, and Mary Cushman. ABO blood type, factor VIII, and incident cognitive impairment in the REGARDS cohort. Neurology, September 2014 DOI: 10.1212/WNL.0000000000000844

Neuroscientists decode brain maps to discover how we take aim.

A new brain map shows how the brain encodes allocentric and egocentric space in different ways during activities that involve manual aiming. The study finding will help healthcare providers to develop therapeutic treatment for patients with brain damage in these two areas, according to the neuroscientists.
Boy swinging tennis racket (stock image). A recent study shows that different regions of the brain help to visually locate objects relative to one’s own body and those relative to external visual landmarks.
Credit: © waltkopp / Fotolia

Serena Williams won her third consecutive US Open title a few days ago, thanks to reasons including obvious ones like physical strength and endurance. But how much did her brain and its egocentric and allocentric functions help the American tennis star retain the cup?

Quite significantly, according to York University neuroscience researchers whose recent study shows that different regions of the brain help to visually locate objects relative to one’s own body (self-centred or egocentric) and those relative to external visual landmarks (world-centred or allocentric).

“The current study shows how the brain encodes allocentric and egocentric space in different ways during activities that involve manual aiming,” explains Distinguished Research Professor Doug Crawford, in the Department of Psychology. “Take tennis for example. Allocentric brain areas could help aim the ball toward the opponent’s weak side of play, whereas the egocentric areas would make sure your muscles return the serve in the right direction.”

The study finding will help healthcare providers to develop therapeutic treatment for patients with brain damage in these two areas, according to the neuroscientists at York Centre for Vision Research. “As a neurologist, I am excited by the finding because it provides clues for doctors and therapists how they might design different therapeutic approaches,” says Ying Chen, lead researcher and PhD candidate in the School of Kinesiology and Health Science.

The study, “Allocentric versus Egocentric Representation of Remembered Reach Targets in Human Cortex,” published in the Journal of Neuroscience, was conducted using the state-of-the-art fMRI scanner at York U’s Sherman Health Science Research Centre. A dozen participants were tested using the scanner, which Chen modified to distinguish brain areas relating to these two functions.

The participants were given three different tasks to complete when viewing remembered visual targets: egocentric reach (remembering absolute target location), allocentric reach (remembering target location relative to a visual landmark) and a nonspatial control, colour report (reporting color of target).

When participants remembered egocentric targets’ locations, areas in the upper occipital lobe (at the back of the brain) encoded visual direction. In contrast, lower areas of the occipital and temporal lobes encoded object direction relative to other visual landmarks. In both cases, the parietal and frontal cortex (near the top of the brain) coded reach direction during the movement.

Story Source:

The above story is based on materials provided by York University. Note: Materials may be edited for content and length.

Journal Reference:

  1. Ying Chen et al. Allocentric versus Egocentric Representation of Remembered Reach Targets in Human Cortex. Journal of Neuroscience, September 2014 DOI: 10.%u200B1523/%u200BJNEUROSCI.%u200B1445-14

Activating single gene could extend human lifespan by 30% – scientists .

Published time: September 10, 2014 18:12

Reuters / Susana Vera

Reuters / Susana Vera

In an experiment on fruit flies, UCLA biologists activated just one gene, AMPK, which extended their lifespan by nearly a third, by helping them to get rid of “cellular garbage” causing old age diseases such as Parkinson’s. Humans have the same gene.

“Instead of studying the diseases of aging — Parkinson’s disease, Alzheimer’s disease, cancer, stroke, cardiovascular disease, diabetes — one by one, we believe it may be possible to intervene in the aging process and delay the onset of many of these diseases,” said author David Walker, an associate professor of integrative biology and physiology at UCLA, whose paper was published last week in the scientific journal Cell Reports.

“We are not there yet, and it could, of course, take many years, but that is our goal and we think it is realistic.”

David Walker (Photo: UCLA)

David Walker (Photo: UCLA)

UCLA’s laboratory conducted the study on 100,000 fruit flies, used because they have been genetically mapped, and scientists can easily mutate just one gene within a population, limiting variables, and ensuring a perfectly controlled experiment.

Those flies with the gene activated in their intestines lived just over eight weeks, instead of the usual six, and, almost as crucially, remained healthier for longer into their lifespans. Projected onto the current US life expectancy of 78, this would correspond to an average lifetime of 101 years.

The impressive results were achieved by activating a process called autophagy, which is stimulated by AMPK.

Autophagy – which translates from Greek as ‘eating oneself’ – allows cells to isolate and discard old, dysfunctional fragments, known as cellular garbage, which can damage healthy cells. Many of the old-age diseases are widely thought to result from decreased rates of autophagy, which eventually build up millions of unhealthy cells in the body.

While humans have the AMPK gene, in most people, it is ‘turned off’.

Researchers also found that switching on the gene in one part of the body results in its activation elsewhere.

“A really interesting finding was when [lead author] Matthew Ulgherait activated AMPK in the nervous system, he saw evidence of increased levels of autophagy in not only the brain, but also in the intestine. And vice versa: Activating AMPK in the intestine produced increased levels of autophagy in the brain — and perhaps elsewhere too,” Walker said.

Fruit flies (Reuters)

Fruit flies (Reuters)

This means that in the future, doctors could perform treatments in easier to reach areas, such as the stomach, even though the main benefits of the therapy could be in harder-to-access ones, like the brain.

The wider conclusions drawn by the team are not just about the single gene AMPK, but demonstrate the key role of autophagy in longevity.

“Matt moved beyond correlation and established causality,” Walker said. “He showed that the activation of autophagy was both necessary to see the anti-aging effects and sufficient; that he could bypass AMPK and directly target autophagy.”

Intriguingly, while the benefits of genetic AMPK treatment appear to be years away, there is already a drug on the market that stimulates existing AMPK genes, which are activated when cells reach a low energy level, as a sort of repair mechanism.

Metformin was synthesized as long ago as 1922, and has been widely used to fight diabetes since the late 1950s, and can now be bought cheaply as a generic. Despite considerable side effects, in recent years it has been touted in multiple studies as decreasing the incidence of cancer and heart disease, and is already used by some as an anti-aging drug, though it cannot be prescribed as such. This appears to dovetail with UCLA’s research on AMPK, which was acknowledged by Walker, who stopped short of advising healthy people to take metformin.

WHO calls for action to reduce global suicide rate of 800,000 a year

  • Poor and middle-income countries rank the worst in the study
  • But some developed nations are worse than others–rates in Britain and Germany worse than much of Europe, US and Australia
  • Guyana has the highest rate of suicide, at 44.2 out of every 100,000, with North and South Korea the second and third worst

The World Health Organization has released global suicide statistics that reveals the United States is about average worldwide while the nations of Guyana, North and South Korea have the highest rates.

More than 800,000 people each year worldwide commit suicide – around one person every 40 seconds – with many using poisoning, hanging or shooting to end their own lives, says the study released Thursday.

In its first global report on suicide prevention, the United Nations health agency said some 75 percent of suicides are among people from poor or middle-income countries and called for more to be done to reduce access to common means of suicide.

Global suicide rate: The report found that suicides take place all over the worldand at almost any age. Globally, suicide rates are highest inpeople aged 70 and over, but in some countries, the highest rates are found among the young.

Global suicide rate: The report found that suicides take place all over the worldand at almost any age. Globally, suicide rates are highest inpeople aged 70 and over, but in some countries, the highest rates are found among the young.

High suicide rates also persist in more developed nations. South Korea, for example, has the world’s third highest rate — 28.9 out of every 100,000 people.

The United States is grouped along with countries such as Australia, Spain and much of Europe whose rates are between 10 and 14.9 per 100,000.

The report found that suicides take place all over the world and at almost any age. Globally, suicide rates are highest in people aged 70 and over, but in some countries, the highest rates are found among the young.

In the 15 to 29-year age group, suicide is the second leading cause of death globally.

The WHO’s director general Margaret Chan said the report was a ‘call for action to address a large public health problem which has been shrouded in taboo for far too long.’

Pesticide poisoning, hanging and firearms are among the most common methods of suicide globally, the report said, and evidence from Australia, Canada, Japan, New Zealand, the United States and Europe shows that restricting access to these means can help to stop people from committing suicide.

In the 15 to 29-year age group, suicide is the secondleading cause of death globally. Suicide rates as a whole go up as the country's income rate goes down

In the 15 to 29-year age group, suicide is the secondleading cause of death globally. Suicide rates as a whole go up as the country’s income rate goes down

Governments should also set up national prevention plans, the report said, noting that currently only 28 countries are known to have such strategies.

The report found that in general, more men die by suicide than women. In richer countries, three times as many men kill themselves as women, and men aged 50 and over are particularly vulnerable.

In poor and middle-income countries, young people and elderly women have higher rates of suicide than their counterparts in wealthy nations, the report found. And women over 70 are more than twice as likely to commit suicide than women aged between 15 and 29.

‘No matter where a country currently stands in suicide prevention, effective measures can be taken, even just starting at local level and on a small scale,’ said Alexandra Fleischmann, a scientist at the WHO’s department of mental health and substance abuse.

Other preventative measures include encouraging responsible reporting of suicide in the media, such as avoiding language that sensationalizes suicide.

Early identification and management of people with mental illness and drug and other substance abusers is also important.

‘Follow-up care by health workers through regular contact, including by phone or home visits, for people who have attempted suicide, together with provision of community support, are essential, because people who have already attempted suicide are at the greatest risk of trying again,’ the report said.

The WHO report was published ahead of world suicide prevention day on September 10.


Thyroid cancer now suspected in 104 youths from Fukushima; government denies link to radiation

From the desk of Zedie.

Thyroid cancer now suspected in 104 youths from Fukushima; government denies link to radiation.

The latest health report from Fukushima Prefecture counts 104 young people with confirmed or suspected thyroid cancer, suggesting a dramatically higher than normal rate. Because nuclear disasters release large amounts of radioactive iodine, which accumulates in the thyroid gland, thyroid cancer is a known risk of such events.

“Many people are being diagnosed with cancer at this time, thanks to the high-precision tests,” said radiation biology professor Yoshio Hosoi of Tohoku University. “We must continue closely examining the people’s health in order to determine the impact of radiation exposure on causing thyroid tumors.”

Yet, in spite of this shocking figure, the prefecture is attempting to downplay any potential connection with the 2011 Fukushima nuclear disaster.

Tumor rate 20 times normal

In March 2011, the Fukushima Daiichi nuclear power plant suffered multiple meltdowns following a massive earthquake and tsunami, and released enormous amounts of radioactive material into the surrounding environment.

On June 30, 2014, the prefecture publicized the result of thyroid gland tests on 300,000 residents who were 18 or younger at the time of the nuclear disaster. Of those with suspected or confirmed thyroid cancer, the average age at the time of the disaster was 14.8. Of the 104 cases, 57 have been confirmed as cancerous and one has been categorized as a benign tumor.

A rate of 104 cases in 300,000 youths translates to an average of nearly 35 cases per 100,000. In contrast, the thyroid cancer rate among teenagers of equivalent age in Miyagi Prefecture, far from Fukushima, is only 1.7 per 100,000.

The Aizu region, just over 80 kilometers from Fukushima, has a rate of 27.7 per 100,000, with examinations still ongoing. The Nakadori region, which includes the city of Fukushima itself and several mandatory evacuation zones, has a rate of 35 per 100,000.

Government denies link, but signs continue to emerge

Fukushima officials have denied any connection between the elevated cancer rates and the nuclear disaster. In addition, some officials have attempted to cast doubt on the findings by noting that it took four years for thyroid cancer rates to rise following the 1986 Chernobyl disaster, and that many of the youths with suspected cancer are not showing any symptoms.

“In order to scientifically compare the results of the development rates of each region, we must take into account age and other characteristics [of the 104 people],” said Hokuto Hoshi, chair of the panel designated to discuss and analyze the results of the health survey.

Critics counter that thyroid cancer screening techniques have significantly improved since 1986, allowing earlier detection.

Indeed, a 2004 study published in the journal Radiation Research found that thyroid cancer rates 18 years after the Chernobyl disaster were directly related to the radioactive iodine dose absorbed by patients back in 1986.

In July 2014, a Japanese doctor wrote an open letter to the newsletter of the Association of Doctors in Kodaira, metropolitan Tokyo, explaining that he believes eastern Japan to be too contaminated by radiation for humans to safely inhabit. The author, Shigeru Mita, had worked as a doctor in metropolitan Tokyo for more than 50 years before deciding that the region was no longer safe.

In the letter, Mita noted that, since the disaster, he had seen dramatic increases in radiation-induced health problems. These problems included “nosebleed, hair loss, lack of energy, subcutaneous bleeding, visible urinary hemorrhage, skin inflammations, coughs and various other non-specific symptoms,” as well as rheumatic muscle problems similar to those seen after the Chernobyl disaster.

Other problems, such as declining white blood cell counts in children under the age of 10 and persistent respiratory symptoms, showed rapid improvement in patients who moved to western Japan.

Sources for this article include:


Salt Doesn’t Cause High Blood Pressure? Here’s What a New Study Says .

Sodium has long been labeled the blood-pressure bogeyman. But are we giving salt a fair shake?

A new study published in theAmerican Journal of Hypertension analyzed data from 8,670 French adults and found that salt consumption wasn’t associated with systolic blood pressure in either men or women after controlling for factors like age.


Why not? One explanation, the authors write, is that the link we all assume between salt and blood pressure is “overstated” and “more complex than once believed.” It should be noted, however, that even though the study found no statistically significant association between blood pressure and sodium in the diet, those patients who were hypertensive consumed significantly more salt than those without hypertension—suggesting, as other research has, that salt affects people differently.

As for the factors that did seem to influence blood pressure, alcohol consumption, age, and most of all BMI were strongly linked to a rise. Eating more fruits and vegetables was significantly linked to a drop.

“Stopping weight increase should be the first target in the general population to counteract the hypertension epidemic,” the study authors wrote.

All of which is surprising given the fact that Americans are bombarded with warnings that we eat far too much: just yesterday, the Centers for Disease Control and Prevention (CDC) issued a reportfinding that 90% of U.S. children eat more sodium than guidelines recommend. Almost half of that comes from 10 processed foods that kids tend to eat a lot of: pizza, bread, processed meats, savory snacks, sandwiches, cheese, processed chicken, pasta dishes, Mexican dishes, and soup.

The CDC firmly believes that salt directly influences blood pressure. “We consider the totality of the evidence,” said Janelle Gunn of the CDC’s Division of Heart Disease and Stroke Prevention at a press conference. “A vast majority of scientific research confirms that as sodium is reduced, so is blood pressure.”

We’ve reported before that the science surrounding salt is crazy confusing, and conflicting studies come out with some frequency. In keeping with the frustrating reality of so many nutrient groups, no one side has definitively won the debate.

In the meantime, it surely can’t hurt to curb some of our salt-laden processed-food intake—but the pounds we shed may be even more helpful than the salt we shun when it comes to lowering blood pressure.

The Built-From-Scratch Heart .

Organ transplantation—removing a piece of one person and sewing it into another—is one of the weirder things that humans have figured out how to do. And our bodies don’t necessarily like it. Immunosuppressive drugs can keep a person’s body from noticing that there’s a foreign object in there, for awhile, at least. But those drugs take their own toll, and eventually, the body can get wise and start to reject the organ.

Even so, actual humans organs are so good at doing their jobs that, in many cases, there isn’t a better alternative. Doctors and researchers have been trying, for instance, to develop an artificial heart for thirty-five years. The first artificial heart, implanted in 1969, kept its recipient alive for three days. On Monday, Carmat, a French biotechnology company that’s created the world’s newest artificial heart—the first to mix synthetic and biological materials—announced that the second of four patients participating in a trial had received their transplant.

The Carmat heart’s valves are made of tissue from a cow’s heart, as are the membranes that come into contact with the patient’s blood. It’s meant to last for up to five years, to extend the life of patients waiting for donor hearts or who aren’t eligible for that sort of transplant. The Carmat’s first test patient received his heart this past December and lived for 75 days; that trial was considered a success.

Even better than a donated heart though, and even better than a functioning artificial one, would be a bioartificial heart, grown from the patient’s own cells. An organ like that the body would recognize as its own.

In the past few years, medical researchers have been making steady progress towards creating one. Cleaning out the cells from the heart’s scaffold—decellularizing it—is the first step. This is what it looks like when you empty a rat’s small heart of all its cells:

What’s left there is a structure of collagen and other proteins that helps the living cells grow and stay in just the right place. The next step is filling the scaffold with new cells, in just the right places, ready to start expanding and contracting. The last step: encourage it to start beating.

In 2008, at the University of Minnesota, a team led by Dr. Doris Taylor used this technique to make a rat’s heart from new cells and convince it to beat. It didn’t pump much blood—just 2 percent of the capacity it might have. But it worked.

Since then, Taylor told Nature last year, she’s managed to create hearts that pump much more efficiently, up to 25 percent of normal capacity. She and other researchers in the field are working on larger hearts too: The scaffold of a pig’s heart, for instance, is close enough to a human’s that it could serve as the basis of bioartificial human heart. These researchers are getting closer to the moment where they’re going to start talking to the FDA about transplanting bioartificial grafts onto human hearts. It won’t be a whole heart at first, most likely. They’ll start with one part—a valve, probably. Soon enough though, it might be possible to fill a whole heart with a patient’s own cells and transplant it back into her body.

How Robotics are Improving Treatment for Head and Neck Cancers.

Head and neck (oropharyngeal) cancer is the sixth most common cancer in the U.S., with nearly 40,000 new cases diagnosed each year. Though tobacco and alcohol use can raise the risk of developing the disease, exposure to the human papillomavirus (HPV) poses an even greater risk. People who have had an oral HPV infection have a 50 times greater risk of developing head and neck cancer versus the general population. Currently, nearly three quarters of head and neck tumors test positive for HPV. A growing number of these newly diagnosed cases are among men in their forties and fifties.

With robotic surgery (left), there is no incision and no scars, while open surgery (right) involves an incicsion from the lip to the ear.

Since the early 1990s, patients with head and neck cancers have been treated primarily with chemotherapy and radiation. Surgery has been avoided as a first line treatment because head and neck tumors can be difficult to reach, requiring invasive surgery that can affect organ function, lead to swallowing difficulties, and require a feeding tube.

Donald Annino, MD, DMD and Tom Thomas, MD, MPHDivision of Otolaryngology at Brigham and Women’s Hospital (BWH), now use state-of-the-art robotics to treat patients with head and neck cancer. Transoral robotic surgery (TORS) is a minimally invasive procedure that uses a combination of high-definition 3D magnification, robotic technology, and miniature instruments to remove a benign tumor or cancerous tissue from a patient’s throat (pharynx or larynx). Since offering the service in 2011, Annino and Thomas have performed over 45 procedures using TORS.

Unlike open surgery, no external incision is required for TORS. Instead, slender robotic arms and tiny surgical tools are guided to the tumor site through the mouth. There are four robotic arms – one equipped with a high definition 3-D magnification camera and three that act as the surgeon’s arms – each holding a different instrument, depending on the particular task. The camera gives the surgeon enhanced detail, true depth of field, and a panoramic view, and the robotic hands allow surgeons a greater range of movement versus the human hand. Enhanced visualization, precision, and dexterity provide important advantages when working in delicate areas of the throat.

“TORS has been a safe option for patients with head and neck cancer. It results in a shorter hospital stay and improved quality of life,” says Annino. Ongoing research, he adds, indicates that TORS also may reduce the need for radiation and chemotherapy later.

Ozone layer that started depleting in 1980s healing .

The protective ozone layer that started depleting heavily in the 1980’s is on a recovery mode according to a new assessment by 300 scientists across the world released on Thursday. “Assessment for Decision-Makers”– a summary document of the Scientific Assessment of Ozone Depletion 2014 published by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) indicates that the ozone layer is expected to recover to 1980 levels before the middle of this century in many parts.

But the news for India is grim. Tropical countries were not significantly affected by the above ozone depletion problem. But, along with severe climate change impacts, India and other tropical regions may face an ozone depletion problem towards the end of the century. Gufran Beig, project director at System of Air Quality Weather Forecasting and Research (SAFAR) of IITM, Pune and only Indian scientist in the international expert review team has flagged off certain ozone concerns for India. Climate change is inducing a change in circulation patterns in the upper layers of the atmosphere that will influence ozone concentration adversely, he has said in his submission.

This undated image provided by NASA shows the ozone layer over the years, Sept. 17, 1979, top left, Oct. 7, 1989, top right, Oct. 9, 2006, lower left, and Oct. 1, 2010, lower right. The fragile ozone layer is finally starting to rebound, says a United Nations panel of scientists. (AP photo)

These changes in the tropical circulation of winds (called Hadley Cell Circulation) will be as a result of climate change and can deplete the ozone layer in future as per the model projections because they tend to shift air in these layers, said Beig. He shared the document he sent to UNEP/WMO with TOI where he adds that concentration of aerosols–suspension of fine liquid droplets in the atmosphere, often particulate air pollution, can negatively impact the ozone layer over the tropics because of their chemical properties. “It has been the opinion of scientists that increasing greenhouse gas emissions and consequent change in the weather system will impact the ozone layer adversely. There has to be immediate measures to cut down on GHG emissions,” he added. Beig has also highlighted that emissions from fossil fuel, bio-fuels, industries and power sector, troposphere or ground-level ozone, a toxic gas is increasing in India which also a problem.

Due to successful implementation of the Montreal protocol across the world that mandated phasing out ozone depleting substances such as chloroflurocarbons (CFCs) used in refrigerators, air conditioners and solvents, the ozone problem has been tackled unto larger extent. But now there is also a problem with the new alternatives. Hydrofluorocarbons (HFCs) which are now widely used (replacing CFCs) do not harm the ozone layer but many of them are potent greenhouse gases and have very high global warming potential. Their emissions are growing at a rate of about 7 % per year. Left unabated, they can be expected to contribute very significantly to climate change in the next decades. We have to avoid them” Beig added., Replacements of the current mix of High GWPs (Global Warming potential) HFCs with alternative compounds with low GWPs would limit this potential problem.
The ozone layer was expected to recover towards its 1980 level by mid-century, or slightly later for Antarctica, where it gets dangerously thin every year between mid-August and November or December.

“The development you saw during the 1990s that the ozone hole got bigger from year to year — that development has stopped, so it has levelled off,” said Braathen.

“We think in about 2025 or thereabouts we’ll be able to say with certainty that the ozone hole is getting smaller,” he added.

Progress could be sped up by as much as 11 years if existing stocks of ozone-depleting substances — many of them stored up in old fridges and fire-extinguishers — were destroyed.

The largest ozone hole on record was about 30 million square km in 2006. The hole now covers about 20 million square km — big enough for the moon to pass through — but may not have peaked this season.

The size of the hole varies from year to year, partly due to temperature in the upper atmosphere.

The reduction of ozone-damaging chemicals would also help the environment, the report said, as many of the substances were also greenhouses gases blamed for global warming.

But the rising levels of other greenhouses gases in the atmosphere had “the potential to undermine these gains,” said the report.

One of the ozone-depleting substances that was supposed to have been phased out – carbon tetrachloride, a solvent – was still being released into the atmosphere suggesting, the report said, illicit production and usage over the past decade.