“Malaria deaths twice as high as was thought,� The Independent has reported today. Many newspapers have covered research that found that malaria claimed 1.2 million lives worldwide in 2010. The Guardian also reveals that the study “demolishes conventional thinking� that almost all malaria deaths are in babies and small children under the age of five.

Malaria-related deaths in the UK were not examined in this study. Malaria is not generally present in the UK, but this preventable disease is commonly contracted by unprepared travellers visiting tropical and subtropical regions. In recent years, newspapers have reported several cases of high-profile people who have caught malaria, including pop star Cheryl Cole and Premiership footballer, Didier Drogba.

The headlines are based on a disease-modelling study that examined a large database, alongside a systematic review of other studies, to identify deaths due to malaria across 105 countries over the past 30 years. The research found that malaria in 2010 was the cause of death for 1.2 million individuals, including 714,000 deaths in children younger than five years and 524,000 in individuals aged five years or older. The results tend to show an increase in mortality from 1980 to peak levels in 2004, but since then a clear decline.

The researchers say that the recent decrease in malaria mortality in Africa in particular is due to an increase in measures to control the disease, which has been supported by international help. They say that support from international donors needs to increase if malaria is to be eradicated.

However, the primary aim of this study was to predict trends over time in malaria mortality, not to try to find causes for malaria mortality or to examine the effectiveness of different solutions to the problem.

 

Where did the story come from?

The study was carried out by researchers from the University of Washington, Seattle, and the University of Queensland in Australia, and was funded by The Bill & Melinda Gates Foundation.
It was published in the peer-reviewed medical journal The Lancet. The papers accurately reflected the findings of the research.

 

What kind of research was this?

This was a modelling study that involved collecting all available data on malaria mortality between 1980 and 2010. During the past 10 years, efforts to tackle malaria have increased. This study aimed to accurately assess the trends in malaria mortality in order to check the progress of these efforts, and to identify areas that need future attention. To do this, the researchers developed a range of models to estimate mortality by age, sex, country and year.

 

What did the research involve?

As part of the Global Burden of Disease 2010 Study, all available data for mortality by cause from 1980 to 2010 are being systematically collated, and the researchers used this along with the Malaria Atlas Project (MAP). The MAP monitored the levels of transmission of Plasmodium falciparum (the parasite that causes the most severe form of malaria) in different countries.

The researchers describe how they used a large database to identify systematically all data for deaths identified as due to malaria. The researchers restricted their analyses to 105 countries that had information on malaria transmission during the 30-year period of interest. For countries that had eliminated malaria during this period, they identified the year of elimination and estimated the number of malaria deaths for the period when transmission was still occurring.

The researchers supplemented the information identified with a search of the global literature to identify published and unpublished ‘verbal autopsy’ studies. These record the probable cause of death based on the deceased's symptoms and likely medical diagnosis. The verbal autopsy method tends to be used in countries that lack a formal and reliable system for registering deaths. These were population-based studies that covered a period of at least one year and provided the number of deaths by cause according to verbal autopsy. The verbal autopsy method tends to be used in countries that lack a formal and reliable system for registering deaths.

In order to develop their models they divided the world into three groups:

• countries from sub-Saharan Africa and Yemen (45 countries)
• countries outside of sub-Saharan Africa (45 countries)
• countries with only Plasmodium vivax malaria (15 countries)

Malaria deaths in countries that only have Plasmodium vivax malaria are lower than others, so for these countries the researchers simply modelled malaria death rate by age. For the other 90 countries the researchers tested different predictive models, including:

• looking separately by sex
• looking separately by age group (less than five years and five years and older)
• looking at the transmission intensity of Plasmodium falciparum malaria, which is a key predictor of the number of malaria deaths

 

What were the basic results?

The study provides extensive mortality data by country. Overall, the researchers observe a fluctuation in the number of malaria deaths worldwide over the 30-year period:

• 995,000 deaths in 1980 (95% confidence interval CI 711,000 to 1,412,000)
• a peak level of 1,817,000 deaths in 2004 (95% CI 1,430,000 to 2,366,000)
• a decrease to 1,238,000 deaths in 2010 (95% CI 929,000 to 1,685,000)

In Africa there were:

• 493,000 deaths in 1980 (95% CI 290,000 to 747,000)
• an increase to 1,613,000 in 2004 (95% CI 1,243 000 to 2,145,000)
• about a 30% decrease to 1,133,000 in 2010 (95% CI 848,000 to 1,591,000)

Outside of Africa, malaria deaths have steadily decreased:

• 502,000 in 1980 (95% CI 322,000 to 833,000)
• down to 104,000 in 2010 (95% CI 45,000 to 191,000)

The researchers estimated that there have been more deaths in people aged five years or older than previous studies have estimated. In 2010 there were 435,000 deaths in over-fives in Africa (95% CI 307,000 to 658,000) and 89,000 deaths in over-fives outside of Africa (33,000–177,000). The comparative 2010 figures for under-fives are 699,000 deaths (95% CI 415,000 to 1,112,000) in Africa and 15,000 deaths (95% CI 4,300 to 31,000) outside of Africa.

Deaths in both under- and over-fives have been decreasing over the past five years. However, the trend of deaths for countries within Africa is different to that for those of countries outside of Africa: in Africa deaths have declined in both the under- and over-fives in the past five years, though deaths in the under-fives still remain clearly higher than those in the over-fives; outside of Africa deaths in both age groups have also steadily declined, though here the mortality rate in the over-fives is higher than those below this age.

 

How did the researchers interpret the results?

The researchers conclude that their findings show that the global malaria mortality burden is larger than previously estimated, especially in adults. They say that the recent decrease in malaria mortality in Africa is due to more measures being taken to control the disease, which has been supported by international help. However, they say that support from international donors needs to increase if malaria is to be eradicated.

 

Conclusion

This study has looked at a lot of data and used systematic methods to examine trends in malaria mortality over the past 30 years. It shows that malaria in 2010 was the cause of death for 1.2 million individuals, including 714,000 deaths in children younger than five years and 524,000 in individuals aged five years or older. The results tend to show an increase in mortality from 1980 to peak levels in 2004, but since then a clear decline.

The researchers say that the recent decrease in malaria mortality in Africa in particular is due to malaria control activities being increased, supported by international help. They say that support from international donors needs to increase further if malaria is to be eradicated.

However, the primary aim of this study was to predict trends over time in malaria mortality, not to try to find causes for malaria mortality or to examine the effectiveness of different solutions to the problem.

Links To The Headlines

Malaria is twice as deadly as first thought after disease claims 1.2million lives in a year. Daily Mail, February 2 2012

Malaria death toll far higher than previously thought. The Daily Telegraph, February 2 2012

Malaria kills 1.2m worldwide - double the level feared. Metro, February 2 2012

Malaria kills twice as many people as previously thought, research finds. The Guardian, February 2 2012

Malaria deaths twice as high as was thought. The Independent, February 2 2012

Links To Science

Murray CJL, Rosenfeld LC, Lim SS, et al. Global malaria mortality between 1980 and 2010: a systematic analysis. Lancet 2012; 379: 413–31

Editorial: New estimates of malaria deaths: concern and opportunity. The Lancet, 2012:379;385

A new study has found that “patients are more likely to die in hospital if they are admitted at the weekend,� according to BBC News. The broadcaster said the research backs up previous studies suggesting patients admitted at the weekend have a lower chance of survival.

The new study in question looked at over 14 million admissions to English NHS hospitals over the financial year of 2009/10. Researchers looked at risk of patients dying from any cause within 30 days of admission, taking into account various other factors that could influence the risk, such as age, reason for admission, and other medical illnesses. During the year there were 187,337 deaths that occurred within 30 days of admission, equating to 1.3% of all those hospitalised. When they looked at factors associated with risk they found a person admitted on a Sunday had 16% increased risk of dying following admission compared to a person admitted on a Wednesday. Conversely, patients were more likely to die mid-week day rather than a Saturday or Sunday.

While the study has found a pattern relating to admission day and the risk of dying, the reasons for this are unknown and it should not be assumed that the pattern is due to staffing levels or the availability of senior staff. There could be various reasons for the relationship; for example, it may be that people who need to see the doctor and be admitted on a weekend have more severe illness than people who would wait until the following Monday to be admitted. While this very large study has found a pattern, it will take further delving to unlock the reasons why, which are likely to be more complex than simply the availability of staff.

 

Where did the story come from?

This study was authored by researchers from University College London and various other institutions in the UK. The study was published in the Journal of the Royal Society of Medicine and received no outside funding.

 

What kind of research was this?

This was a retrospective cohort study aiming to see if being admitted at the weekend carried a higher risk of mortality than admission on a weekday. To do so the researchers looked at all hospital admissions that occurred within the NHS over the 2009/10 financial year. It was concerned with ‘30-day mortality’, that is, deaths occurring within 30 days of a hospital admission (either in or out of hospital).

The researchers adjusted their analysis to account for various factors that could have affected this risk, but do not describe how the severity of patients’ conditions was taken into account. This means it is difficult to tell how effectively this potentially major confounder has been accounted for. The severity of a patient’s illness, the type of care provided to them and the differences in their outcome are likely to relate to each other in complex ways, and so the topic will need further careful analysis.

 

What did the research involve?

The researchers analysed all admissions to the English National Health Service (NHS) during the
financial year 2009/10. They linked admission records to official mortality data from the Office of National Statistics to identify all deaths that occurred within the 30 days following an admission (both those occurring in or out of hospital).

Using their data the researchers then developed statistical models to account for risk of death following admission. In their main model they adjusted for factors that were likely to have a strong effect on mortality risk:

• age
• sex
• ethnicity
• whether or not the admission was an emergency
• source of admission (for example, from home or transfer from another hospital)
• diagnosis; number of previous emergency admissions
• number of previous ‘complex’ admissions
• medical co-morbidities
• social deprivation
• hospital trust
• day of the year (seasonality)
• day of the week admission occurred on

They looked at both risk associated with being admitted over the weekend, and with staying in hospital over the weekend (admitted during the week but being an inpatient over the weekend).

 

What were the basic results?

There were 15,061,472 admissions to the NHS in England over this one-year period, and the researchers had information on 30-day mortality and other patient characteristics for 14,217,640 of them (95% of all admissions). There were 187,337 deaths in hospital within 30 days of admission. Admission on weekend days was associated with an increased risk of 30-day death compared with admission on weekdays:

• Sunday admissions were associated with a 16% increased risk compared to those on a Wednesday (hazard ratio [HR] 1.16, 95% confidence interval [CI] 1.14 to 1.18)
• Saturday admissions were associated with an 11% greater risk versus Wednesday admissions (HR 1.11, 95% CI 1.09 to 1.13).

Conversely, deaths were more likely to occur during the week than at the weekend. Staying in hospital on a Sunday was associated with a slightly lower risk of death than staying in hospital on a Wednesday (HR 0.92, 95% CI 0.91 to 0.94), as was staying in hospital on a Saturday (HR 0.95, 95% CI 0.93 to 0.96).

There were 284,852 deaths overall – both in an out of hospital – and 34% of people that died did so after they had been discharged from hospital. Results for the researchers’ subsequent model, examining all deaths, not just those occurring in a hospital, were similar.

 

How did the researchers interpret the results?

The researchers conclude that admission to hospital at the weekend is associated with increased risk of dying within 30 days of admission. However, death is more likely to occur on a mid-week day than a weekend.

 

Conclusion

The main finding of this study was that being admitted to hospital at the weekend (Saturday or Sunday) is associated with a significant increased risk of death over the following 30-days. This study has strengths in that it has used an extremely large and reliable data set representative of almost all hospital admissions within the NHS in England during one financial year. The researchers’ model also accounted for a wide range of medical and sociodemographic factors and characteristics of admission that could have influenced the risk of death.

While the researchers’ models adjusted for a variety of important confounders, it is difficult to see from the report how they did this, making it difficult to decide whether all relevant factors have been appropriately adjusted for. Most importantly, this study has not examined the reasons why there may be increased risk of death with weekend admission, so no assumptions should be drawn about staffing levels or the availability of senior staff.

It is important to be aware that an increased risk of subsequent death of 16% (Sunday compared to Wednesday) is a relative measure, representing an increase of only about two extra deaths for every 1,000 people admitted on a weekend compared to a weekday (a x 0.16 relative increase beyond a 13 per 1,000 average baseline risk of death).

The researchers do offer some potential reasons for the patterns seen, putting forward the hypothesis that patients admitted at the weekend may include patients whose illness may have been severe enough to justify not waiting until a week day, while those who were less ill may have waited rather than going to the hospital at the weekend. This is an interesting, and indeed plausible theory, but it is not clear how the researchers adjusted severity of illness in their analysis, and therefore it is not possible to confirm if this phenomenon accounts for the small absolute difference in deaths seen.

Links To The Headlines

You ARE more likely to die if taken to hospital at weekend: Study confirms that NHS care is worse on a Saturday and Sunday. Daily Mail, February 2 2012

Hospital patients more at risk at weekends. The Guardian, February 2 2012

Risk of dying 'significantly' higher if you go into hospital on Sunday. Metro, February 2 2012

Links To Science

Freemantle N, Richardson M, Wood J, et al. Weekend hospitalization and additional risk of death: An analysis of inpatient data. Journal of the Royal Society of Medicine. Published online on February 2 2012

Britain is in the grip of a new “flesh-eating bug spread by sneezes and coughs�, according to the front page of today’s Metro. The newspaper says that the bacteria are spreading across Britain, as they can be caught through people coughing and sneezing on crowded trains and buses.

This unsettling news put some of the Behind the Headlines team off grabbing their free copy of the Metro at the station this morning, not because of the fear of catching deadly germs from the paper, but because its report was alarmist and overblown. The basis of this news was a laboratory study that investigated why healthcare-acquired meticillin-resistant staphylococcus aureus (MRSA) bacteria rarely cause infections in healthy individuals. The study found that healthcare-acquired MRSA has a high level of antibiotic resistance, but that this property comes at a cost of reduced virulence (being less able to cause infection). Conversely, the study found that the type of MRSA that is usually caught in a community setting is more virulent, but weaker against treatment with antibiotics.

This study has not investigated the transmission, effects or number of cases of community-acquired MRSA in the UK, the discussion of which formed the basis of many news reports on the research. The researchers state that MRSA outside the healthcare system and in the community is a growing concern, but cases are still very rare. This interesting research contributes to our knowledge of MRSA, rather than warning us of an invasion of airborne superbugs.

 

Where did the story come from?

The study was carried out by researchers from the University of Bath and the University of Nottingham in the UK; University College Dublin in Ireland; and Texas A&M Health Science Centre and the University of Texas in the US. It was funded by the UK Medical Research Council and a Biotechnology and Biological Sciences Research Council Studentship. The study was published in the peer-reviewed Journal of Infectious Diseases.

This story was widely covered. Most reports were alarmist, concentrating on the supposed emergence of a dangerous, highly infectious new form of community-acquired MRSA. Many newspapers suggested that transmission is easy, that it can lead to a “flesh-eating form of pneumonia�, and that cases are on the increase. These claims seem to be based on the press release for the research rather than the research paper itself. The study was actually laboratory-based research that had investigated why healthcare-acquired MRSA bacteria rarely cause infections in healthy individuals. Although there was some investigation of community-acquired MRSA, the results do not justify the news coverage.

 

What kind of research was this?

This was a laboratory-based study. It aimed to examine why healthcare-acquired MRSA bacteria rarely cause infections in healthy individuals. Healthcare-acquired, or hospital-acquired, means that the bacteria cause infections that mostly occur in healthcare environments.

The researchers initially covered the nature of MRSA and how it resists certain types of antibiotics. It is already known that MRSA is resistant to the antibiotics meticillin and oxacillin because it has acquired a piece of DNA called a ‘mobile genetic element’. Meticillin is an old antibiotic that is now no longer used and has been replaced by flucloxacillin.

Many staphylococcus aureus bacteria have now also developed resistance to the penicillin group of antibiotics (because they produce enzymes that can make penicillin inactive), but they are usually still susceptible to the antibiotic flucloxacillin. MRSA, however, does not have this susceptibility to flucloxacillin, and is, therefore, harder to treat than most staphylococci bacteria, needing stronger antibiotics still.

One particular genetic element that is key for deciding the properties of MRSA is called the ‘staphylococcal cassette chromosome mec’ (SCCmec). There are several different versions of this cassette, which each provide bacteria with slightly different properties. The researchers state that healthcare-acquired MRSA have type I, II or III SCCmec elements, whereas community-acquired MRSA have type IV and V elements. These different cassettes all contain a gene (mecA) that codes for a protein called PBP2a, located in the cell wall of the bacteria. PBPs (penicillin binding proteins) are a normal part of the cell wall of many bacteria. Many antibiotics work by inactivating PBPs, which cause the bacteria to die. However, the version of PBP encoded by mecA, PBP2a, is less sensitive to antibiotics, allowing the bacteria to survive.

 

What did the research involve?

The researchers initially determined whether deleting the mecA gene, which encodes the PBP2a cell wall protein, affects the toxicity of MRSA. They then took a healthcare-acquired MRSA strain and a version of this strain that they genetically modified to delete the mecA gene, and performed tests to see how each was able to break up a type of immune cell called a T cell in the laboratory.

The researchers then investigated the ability of the different strains to respond to ‘signalling molecules’, which normally cause the bacteria to activate their production of toxins. The virulence of these strains was confirmed using mouse experiments.

The researchers then compared the production of the PBP2a cell wall protein, T-cell toxicity and the resistance of healthcare-acquired MRSA to antibiotics, compared with community-acquired MRSA.

 

What were the basic results?

The researchers found that deleting the mecA gene caused the MRSA to become more toxic. This was because the expression of mecA results in cell wall changes that interfere with MRSA’s ability to detect or respond to signals to switch on toxin expression. MRSA with mecA deleted was also more virulent in a mouse model, causing mice to lose weight or die.

The researchers then compared MRSA strains with different SCCmec elements: those with type II elements (typical of healthcare-acquired MRSA) and those with type IV elements (typical of community-acquired MRSA). They found that typical community-acquired MRSAs had lower resistance to the antibiotic oxacillin, were more toxic to the immune system’s T-cells and expressed less PBP2a.

 

How did the researchers interpret the results?

“As a direct result of its high level of antibiotic resistance, healthcare-acquired MRSA is impaired in its ability to cause infection, which can explain its inability to cause infection in community settings, where antibiotic usage and the prevalence of susceptible patients are low.� In other words, healthcare-acquired MRSA makes a trade-off, sacrificing its ability to spread to healthy individuals in order to fight off a greater range of antibiotics.

 

Conclusion

This interesting study helps explain why healthcare-acquired MRSA infections are rarely found in healthy individuals. It found that expression of a gene that produces one of the proteins responsible for MRSA’s antibiotic resistance caused it to be less toxic. It also showed that typical community-acquired MRSA strains express less of this antibiotic-resistance protein, but are more toxic.

However, this intriguing lab study did not investigate the transmission, effects or number of cases of community-acquired MRSA in the UK, the discussion of which formed the majority of the news reports. On this basis, the research itself does not support the claims that we are under siege from an ‘airborne, bacteria-resistant, flesh-eating superbug’, as newspapers have today suggested.

Links To The Headlines

Flesh-eating bug spread by sneezes and coughs. Metro, February 2 2012

Deadly new superbug is heading for Britain. Daily Express, February 2 2012

New deadly MRSA strain on its way to the UK from USA. Daily Mirror, February 2 2012

Super-strong MRSA bug heading to UK. The Sun, February 2 2012

Flesh-eating bug spread by coughs and sneezes spreading across the UK. Daily Mail, February 2 2012

Links To Science

Rudkin JR, Edwards AM, Bowden MG et al.Methicillin Resistance Reduces the Virulence of Healthcare-Associated Methicillin-Resistant Staphylococcus aureus by Interfering With the agr Quorum Sensing System. Journal of Infectious Diseases, February 1 2012

“Sugar is so harmful that it should be controlled and taxed in the same way as tobacco and alcohol,� according to health experts quoted in today’s Daily Express. The researchers say that sugar indirectly contributes to 35 million deaths a year worldwide.

The news is based on a comment article by US health scientists, who argue that there has been a massive rise in diseases such as heart disease, cancer and diabetes since we began eating more sugar contained in processed food. The researchers argue that many of the health effects of excess sugar consumption are similar to those of alcohol, and that sugar should, therefore, be controlled and taxed in a similar way. They advocate introducing a tax on processed foods with added sugar, limiting sales during school hours and placing age limits on purchase. Interestingly, the authors rate sugar as more dangerous to health than saturated fat and salt, which they call dietary “bogeymen�.

It is important to highlight that the researchers’ article is a comment piece and, therefore, primarily reflects their views and opinions, rather than presenting direct research on the issue. While it is certainly an interesting concept, there is still a lack of evidence supporting the effectiveness of such measures and, crucially, whether the public would actually accept them.

 

Where did the story come from?

The article was written by researchers from the University of California. There is no information about any external funding. It was published in the comment section of the peer-reviewed scientific journal Nature.

The article was covered fairly by the papers, many of which included comments from UK experts including the UK Food and Drink Federation, which represents food manufacturers. The BBC also quoted an expert from the British Heart Foundation, who reportedly said that taxing salt and fat alongside sugar should also be considered.

 

What kind of article was this?

This was a comment piece in which experts discuss the global burden of general chronic disease related to sugar consumption and the need to regulate certain dietary items. In particular, the authors draw parallels between the health effects of sugar and the use of alcohol and tobacco, arguing that sugar should be regulated in a similar manner.

It is important to highlight that this was a comment piece only and, as such, it primarily reflects the views and opinions of the authors. A formal systematic review of the literature does not appear to have been conducted and, as such, it is not certain whether all relevant evidence and resources related to sugar consumption and its health effects will have been consulted.

Also, the short piece looks at the issue from a global perspective and, therefore, is not a direct commentary on sugar consumption in the UK. In fact, a map showing average added sugar consumption per day across different nations shows that people in the UK consume a relatively low amount of sugar, at least compared with the rest of the world. Much of the article’s content may be focused on policies suited to the US, which has by far the greatest per-head sugar consumption, at more than 600 calories worth of sugar per day.

 

What does the article say?

The article points out that, for the first time in human history, non-communicable diseases such as heart disease, cancer and diabetes, pose a greater health burden worldwide than infectious disease. While alcohol, tobacco and diet are all targeted as risk factors for these diseases by policymakers, only the first two – alcohol and cigarettes – are regulated by governments to protect public health. (Although, as the report points out, Denmark taxes food high in saturated fats and is now considering taxing added sugar.) The authors argue that fat and salt have become the current “dietary bogeymen� in the US and Europe, but that most doctors no longer believe that fat is the “primary culprit� of such disease. Doctors are apparently calling for attention to be turned towards the dangers of excess sugar consumption.

The authors estimate that over the past 50 years sugar consumption has tripled worldwide, mainly as a result of it being added to cheap processed foods. While excess sugar is thought to be a key cause of the obesity epidemic, they argue that obesity itself is not the root cause of disease but that its presence is a marker for metabolic damage. This, they say, could explain why 40% of those with metabolic syndrome (a collection of the key metabolic changes that lead to heart disease and diabetes) are not obese.

 

Why do they think sugar is dangerous?

The authors say that although sugar is described as “empty calories�, a growing body of evidence suggests that fructose (one component of table sugar) can trigger processes that lead to liver toxicity and a host of other chronic diseases. “A little is not a problem but a lot kills – slowly,� they say.

The authors argue that sugar meets all the four criteria used by health policy makers to justify the regulation of alcohol. These are:

• Unavoidability. While sugar was only available as fruit and honey at certain times of the year to our ancestors, it is now present in nearly all processed foods. In some parts of the world people are consuming more than 500 calories worth of sugar per day.
• Toxicity. There is growing evidence that excess sugar has an effect on human health beyond simply adding calories and can cause many of the same problems as alcohol, including high blood pressure, high blood fats, insulin resistance and diabetes.
• Potential for abuse. The authors argue that, like tobacco and alcohol, sugar acts on the brain to encourage dependence. Specifically, it interferes with the workings of a hormone called ghrelin (which signals hunger to the brain) and it also affects the action of other important compounds.
• Negative impact on society. The economic and human costs of these diseases place excess consumption of sugar in the same category as smoking and drinking.

 

What do they think should be done?

While the authors accept that sugar is “natural� and a “pleasure�, they argue that, like alcohol, too much of a good thing is toxic. Strategies to reduce consumption of alcohol and tobacco show that government controls, such as taxation and imposing age limits, work better than educating people. They make several proposals for controlling sugar, including:

• taxing any processed foods with added sugar, including drinks
• reducing the hours during which retailers can sell food containing added sugar
• tightening the licensing requirements on vending machines and snack bars selling sugary products
• controlling the numbers of fast food outlets and convenience stores
• limiting sales during school hours or imposing an age limit for drinks with added sugar

Finally, they argue that regulating sugar will not be easy, but it can be done with enough pressure for change, citing bans on smoking in public places as an example of what can be achieved.

 

What does this mean for me?

This article will be of interest to food scientists, health policy makers and the public alike, but the use of strategies to restrict the consumption of added sugar is complicated and, indeed, controversial. The implications of such moves would need to be considered in both medical and societal terms. They would need both medical evidence to support their effectiveness and assurance that the public would accept drastic changes, such as age limits on buying sweets. For example, in recent years, Denmark has imposed taxes on fatty foods, a move that has divided opinions greatly.

It is generally accepted that added sugar or excessive sugar consumption is bad for health and dietitians advise restricting sugar intake to the occasional “treat�. However, to what extent sugar is directly to blame for the rise in chronic disease and how much is due to other dietary components, such as saturated fat and salt, is open to debate. The current article does not appear to be a formal systematic review of the literature, and it is not certain whether all relevant evidence and resources related to sugar consumption and its health effects have been consulted. As such, it should be considered primarily to reflect the views and opinions of the authors.

In the UK at present, policymakers generally favour encouraging healthier eating through education and the provision of healthier options. This is carried out through public health campaigns such as 5 A DAY or by introducing new food ranges to schools. Whether this approach alone is adequate and whether healthier eating patterns should be encouraged by government regulation, is a crucial area of debate.

Links To The Headlines

Sugar 'is toxic and must be regulated just like cigarettes', claim scientists. Daily Mail, February 2 2012

Sugar tax needed, say US experts. BBC News, February 2 2012

Tax harmful sugar. Daily Express, February 2 2012

Links To Science

Lustig RH, Schmidt LA, Brindis LD. Public health: The toxic truth about sugar. Nature, February 2 2012

“Mind-boggling! Science creates computer that can decode your thoughts and put them into words,� the Daily Mail’s headline exclaimed today, while The Daily Telegraph heralded an era in which a “mind-reading device could become a reality�.

You’d be forgiven for thinking famous mind readers such as Derren Brown had just produced a telepathy implant. Instead, these reports are from a small study of 15 people that culminated in researchers being able to reconstruct the sound patterns of words using brain activity alone.

This research involved attaching electrical sensors directly to brains of people undergoing brain surgery to understand how they processed individual words that were played to them. The researchers demonstrated that the brain breaks words down into complex patterns of electrical activity. They were then able to create a mathematical algorithm that decoded and translated the brain activity back into a rough version of the original sound.

But the reconstructed words were not of good enough quality to be recognised by a human listener when played. The words were only recognised when the original and reconstructed sound patterns were compared visually.

This exciting and new research does raise the prospect of brain activity one day being translated into words using an implant. Such technology could help the vast numbers of people suffering from problems affecting speech. But it is important to recognise that this research is in its very early stages and a clinically effective implant is likely to be a long way off.

 

Where did the story come from?

The study was carried out by a collaboration of North American universities led by researchers from the University of California, Berkeley. It was funded by several academic grants and was published in the peer-reviewed science journal Public Library of Science (PLoS) Biology.

The researchers report that the human brain has evolved complex mechanisms to decode highly variable sounds into meaningful elements of language, such as words. Understanding this complex decoding in humans has proved difficult, as it requires recording brain activity on the exposed brain (with the skull removed).

This study took advantage of cases of rare brain surgery for epilepsy and brain tumours that allowed researchers to measure brain activity by attaching sensors directly to the brain surface. This provided a unique opportunity to understand how the human brain recognises speech.

This study received wide media coverage due to its futuristic appeal and was often given a sci-fi angle, with some suggesting a “mind-reading device could become reality�. This research does raise the possibility of developing a device that could interpret thoughts into speech in the future. However, it is important to note the authors’ own caution - that the technology of translating thoughts into words needs to be vastly improved before such a device could become a reality.

 

What kind of research was this?

This was a small study of 15 people undergoing brain surgery for epilepsy or brain tumour. It looked at whether the complex brain activity involved in processing spoken words, such as the sound wave form and syllable rate, could be reconstructed using a computer program.

The researchers believe that the brain processes internal thoughts in a similar way to hearing sounds, and hope that this type of technology could eventually be used to help those who cannot talk, such as those in a coma or in the much-feared “locked-in syndrome�.

 

What did the research involve?

Fifteen patients undergoing brain surgery for epilepsy or brain tumour were asked to listen to 47 real or invented words and sentences from different English speakers. All patients had normal language capabilities when they were enrolled in the study.

During this process electrical signals from the brain were recorded using multiple sensors attached directly to the part of the brain called the lateral temporal cortex, which includes the superior temporal gyrus (STG), thought to be very important in the processing of speech.

To understand and mimic the brain activity involved in processing heard words, the researchers used an approach referred to as “stimulus reconstruction�. In this case, the stimulus was hearing a spoken word.

Hearing words causes a large amount of brain activity involved in recognising and processing the different aspects of the sounds of the words, for example the different sound frequencies and timing of syllables. The word reconstruction involved creating a mathematical program (like that used in computer software) capable of decoding the vast amount of brain activity in such a way that it was possible to identify the original words heard by the participant.

The reconstructed signals from different mathematical models (linear and non-linear) were compared to those detected directly from the brain surface to see how good they were at mimicking the brain’s activity when hearing spoken words. The researchers also used the models to identify the most important areas of the brain involved in processing this information and what other factors influenced the accuracy of the sound reconstructions.

 

What were the basic results?

When constructing the mathematical models they found that the STG region of the brain was important in creating an accurate prediction of the sound pattern of the original word.

The sound patterns generated by the mathematical model allowed the identification of specific words to be generated directly from the brain activity of patients listening to the words. These took the form of visual representations of the word sound pattern. A total of 47 words were presented in pairs and, on average, the model correctly identified the word in approximately nine out of every ten instances (89%). This was significantly better than 50% correct identification, which would be seen simply by guessing.

Importantly, however, the quality produced from reconstructing the words was not good enough for them to be recognised by a human listener when played. The words were only recognised when the original and reconstructed sound patterns were compared visually.

The researchers found that different types of mathematical models performed better at reconstructing the sounds of words with particular characteristics.

 

How did the researchers interpret the results?

The authors concluded that their results demonstrated that key aspects of speech signals can be reconstructed from STG activity.

 

Conclusion

This study of 15 people undergoing brain surgery has demonstrated a method of reconstructing the sound of a heard word using only the signals obtained from the brain. This study represents an important progression in the field of speech reconstruction, which has the potential to improve the lives of many who suffer from speech difficulties in the future.

But the words, when reconstructed, were not of good enough quality to be recognised by a human listener when played. The words could only be identified when the original and reconstructed sound patterns were compared visually. The researchers suggest that improving the brain sensors detecting the STG brain activity may, in the future, improve the reconstructed sound to a level that could be understood by a person listening.

The mathematical formula used to reconstruct the words is at a very early stage and would need a significant amount of improvement and development before it could be considered for use in an implant or similar device in the future. Similarly, future speech reconstruction research would need to demonstrate it was effective in a large range of words, sentence patterns and languages. Currently, the mathematical program has only been tested on a limited vocabulary of 47 English words.

This research represents an intriguing first demonstration of the potential of speech reconstruction technology to transform the lives of people with communication problems in the future.

Links To The Headlines

Science decodes 'internal voices'. BBC News, February 1 2012

Mind-reading device could become reality. The Daily Telegraph, February 1 2012

Mind-boggling! Science creates computer that can decode your thoughts and put them into words. Daily Mail, February 1 2012

Mind-reading program translates brain activity into words, The Guardian, February 1 2012

Links To Science

Pasley BN, David SV, Mesgarani N, et al. Reconstructing Speech from Human Auditory Cortex. PloS Biology. Published online January 31 2012

“Heartburn pills taken by thousands of women ‘raise risk of hip fractures by up to 50 per cent’,� the Daily Mail reported today. The headline is based on a large new study of drugs called proton pump inhibitors (PPIs), which are commonly used to treat heartburn, acid reflux and ulcers.

The study found that post-menopausal women who regularly took PPIs for at least two years were 35% more likely to suffer hip fracture than non-users, a figure that increases to 50% for women who were current or former smokers. However, although this increase in risk is large, the overall risk of fractures remains small.

This was a large, well conducted study that suggests that long-term use of PPIs is associated with a small increase in risk of hip fracture, although the researchers point out that the risk seems to be confined to women with a history of smoking. Unlike previous research, this study took careful account of other factors that might affect risk such as body weight and calcium intake.

Women who are concerned about their use of PPIs are advised to consult their GP.

 

Where did the story come from?

The study was carried out by researchers from Massachusetts General Hospital, Boston University and Harvard Medical School and was funded by the US National Institutes of Health. The study was published in the peer-reviewed British Medical Journal.

Although the Mail’s headline is technically correct, it gives the impression that these drugs carry a very large increase in the risk of hip fracture. In fact, the study found that, in absolute terms, the increase in risk for regular users was small. Researchers found that among the women in the study who regularly used PPIs, about 2 in every 1,000 fractured a hip each year. In non-users, this figure was about 1.5 in every 1,000. This is a increase of about 5 fractures a year in every 10,000 women taking PPIs.

The Mail did point out this “absolute difference� towards the end of its story. Both the Mail and the BBC included comments from independent experts.

 

What kind of research was this?

The researchers point out that PPIs are among the most commonly used drugs worldwide. In the US they are available over the counter, but in the UK are available only on prescription. They are used for symptoms of heartburn, gastro-oesophageal reflux disease (GORD) and stomach ulcers. PPIs are thought to work by reducing acid production in the stomach. Concern has grown over a potential association between long-term use of these drugs and bone fractures, although the researchers say that previous studies have had conflicting results and many did not take other factors (called confounders) that might affect the risk of fracture into account.

In their cohort study of nearly 80,000 post-menopausal women, the researchers set out to examine the association between long-term use of PPIs and the risk of hip fracture. Unlike a randomised controlled trial, a cohort study cannot prove cause and effect. However, cohort studies enable researchers to follow large groups of people for long periods and they are useful for looking at potential long-term risks and benefits of treatments. The study was prospective, which means it followed participants in time, rather than collecting information retrospectively. This makes it more reliable.

 

What did the research involve?

This study took its data from a large ongoing US study called the Nurses Health Study, which began in 1976 and which sent health questionnaires every two years to 121,700 female nurses aged 30-55.

From 1982 participants were asked to report all previous hip fractures and in each biennial questionnaire, women were asked if they had sustained a hip fracture over the previous two years. Those who reported a hip fracture were sent a follow-up questionnaire asking for more details. Fractures from bad accidents, such as falling down a flight of stairs, were excluded from the study. A review of medical records for 30 of the women validated all self-reported fractures.

From 2000 to 2006 the women were asked if they had regularly used a PPI in the previous two years. In earlier questionnaires (1994, 1996, 1998 and 2000), the women were also asked if they had regularly used other drugs for acid reflux, called H2 blockers.

The biennial questionnaires also included questions on other factors including menopausal status, body weight, leisure activities, smoking and alcohol use, use of hormone replacement therapy (HRT) and other medicines. Researchers used a validated food frequency questionnaire to calculate the women’s total intake of calcium and vitamin D.

They then analysed the data for any association between regular use of PPIs and hip fracture, adjusting their findings for key confounders such as body weight, physical activity, smoking, and alcohol and calcium intake. They also took into account whether the reasons for using a PPI might have affected the results.

Finally, they carried out a systematic review combining their results with 10 previous studies on the risk of hip fracture and the long-term use of PPIs.

 

What were the basic results?

The researchers documented 893 hip fractures during the period of the study. They also found that, in 2000, 6.7% of women regularly used a PPI – a figure that had risen to 18.9% by 2008.

• Amongst women who had regularly taken a PPI at any time, there were 2.02 hip fractures per 1,000 person years, compared with 1.51 fractures per 1,000 person years among non-users.
• Women who regularly used PPIs for at least two years had a 35% higher risk of hip fracture than non-users (age adjusted hazard ratio (HR) 1.35; 95% confidence interval (CI) 1.13 to 1.62), with longer use associated with increasing risk. Adjustment for risk factors, including body mass index, physical activity and intake of calcium did not alter this association (HR 1.36; CI 1.13 to 1.63).

The increased risk did not change when researchers also took into account the reasons for PPI use:

• Current and former smokers who regularly used PPIs were 51% more likely to have a hip fracture than non-users (HR 1.51; (CI) 1.20 to 1.91).
• Among women who never smoked there was no association between PPI use and hip fracture (HR 1.06; (CI) 0.77 to 1.46).
• In a meta-analysis of these results with 10 previous studies, the risk of hip fracture in users of PPI was higher compared with non-users of PPIs (pooled odds ratio 1.30; CI 1.25 to 1.36).

The researchers also found that two years after women stopped taking PPIs, their risk of hip fracture returned to a similar level to that in women who had never taken them. Also, women taking H2 blockers had a “modest� increased risk of hip fracture but the risk was higher in women who took PPIs.

 

How did the researchers interpret the results?

The researchers conclude that their results provide “compelling evidence� of a risk between PPI use and hip fracture. They say the findings suggest that the need for long-term, continuous use of PPIs should be carefully evaluated, particularly among people who have smoked or are still smokers.

They suggest that PPIs may increase the risk of fracture by impairing the absorption of calcium, although in this study the risk of fracture was not affected by dietary calcium intake. The finding that the risk was confined to women with a history of smoking (an established risk factor for fracture) indicates that smoking and PPIs may act together (have a “synergistic effect�) on fracture risk.

 

Conclusion

This large study had several strengths. Unlike some previous studies, it collected information on and took into account other key risk factors for fracture, including body weight, smoking, alcohol use and physical activity. It also looked at the women’s use of PPIs every two years (rather than just asking them once) and took into account variations in use during this time in their analysis.

 

However, as the authors note, it also had some limitations:

• It did not ask about the brands of PPI used, nor the doses of PPI the women took, both of which could affect risk of fracture.
• The information about hip fracture was self-reported and not confirmed by medical records (although a smaller study has found self-reporting of hip fracture to be reliable).
• Also, the study did not record the women’s bone mineral density (BMD). Low BMD is an important risk factor for fracture and adding a measure of this could have strengthened the study.

Finally, because this was a cohort study, other factors both measured and unmeasured may have affected the results, even though researchers took many of these into account in their analysis. Socio-economic status and education, for example, were not established. Because this was a study of registered nurses, the applicability of the results to other socio-economic groups might be limited.

This study found that the long-term, regular use of these drugs is associated with a small increased risk in hip fracture among older women, a risk that seems to be confined to past or current smokers. Women who regularly take PPIs and who are concerned about these findings are advised to talk to their GP. Whether any change in use of this commonly prescribed drug is needed requires further study. 

Links To The Headlines

Indigestion drugs taken by millions linked to hip fractures. The Daily Telegraph, February 1 2012

Heartburn pills taken by thousands of women 'raise risk of hip fractures by up to 50 per cent'. Daily Mail, February 1 2012

Ulcer drugs 'link to fractures'. BBC News, February 1 2012

Links To Science

Khalili H, Huang ES, Jacobson BC, et al. Use of proton pump inhibitors and risk of hip fracture in relation to dietary and lifestyle factors: a prospective cohort study. British Medical Journal. Published online January 31 2012

 

“Drinking just one glass of milk a day could boost your brain power,� the Daily Mail has reported today. Milk is being hailed as a memory aid, the newspaper says, with a study showing that dairy products could “help stave off mental decline�.

The study on which the story is based found that adults with higher intakes of milk and other dairy products did better in memory and other brain function tests than those who drank little or no milk.

However, the Mail’s excitement is misplaced – the study did not show that milk was responsible for better mental performance. The type of study reported cannot show cause and effect. All it showed was that, at one point in time, people who drank more milk performed better in mental tests than those who drank less. It is possible that many other things influenced people’s performance in mental function tests, including occupation, stress levels, even how well they were feeling at the time they took the tests.

Milk may be good for your bones but so far there is no good evidence that it improves mental performance.

 

Where did the story come from?

The study was carried out by researchers from the University of Maine in the US and the University of South Australia. It was published in the peer-reviewed International Dairy Journal. It was partly funded by the Maurice de Rohan International Scholarship, the University of South Australia and the National Heart, Lung and Blood Institute, the National Institute on Aging and the National Institutes of Health, all in the US.

The Mail reported the study uncritically. Its suggestion that milk could help stave off mental decline is not supported by this research. It’s worth noting that the study was released to the press by a US PR company on behalf of the National Fluid Milk Processor Promotion Board, which is an industry-funded organisation set up by the US government to promote milk. This may explain how it found its way into the Daily Mail.

 

What kind of research was this?

This was a cross-sectional analysis of nearly 1,000 participants that aimed to investigate whether dairy food intake was associated with mental functioning. This type of study can provide a “snapshot� of various lifestyle factors and people’s health at one point in time, but it cannot establish cause and effect. A cohort study that recorded people’s dairy consumption over time and then tested their mental function more than once would provide more reliable results although even this type of study cannot establish cause and effect.

The researchers say that as the whole population ages, cognitive decline and dementia place a severe strain on both families and healthcare systems. Change in diet may have a role in preventing cognitive decline, but they say little attention has so far been paid to the relationship between dairy foods and mental performance.

The researchers say there is growing evidence that dairy products may be of benefit to cardiovascular health. Many experts would dispute this. Some dairy foods are high in saturated fat, which is associated with obesity and heart disease. Most dietitians advise a restricted intake of dairy products or consumption of low-fat varieties.

 

What did the research involve?

Researchers recruited 1,049 adults of all ages who were taking part in research looking at cardiovascular health and mental functioning. They collected health and lifestyle data from the participants by various methods including self-reports, medical examination, diagnostic interviews, health records and neuropsychological testing.

After excluding those who did not fulfil eligibility criteria (for example, because dietary or cognitive data were missing or because they had suffered a stroke), they were left with 972 participants.

To measure mental functioning of the participants, the researchers used a validated series of tests measuring memory, verbal recall, visual–spatial perception, organisational and verbal skills, and abstract reasoning ability. For dietary intake, they used a recognised questionnaire that included questions about nutrition and lifestyle.

The dietary component of this questionnaire included questions about dairy products. Milk was considered separately from total dairy foods. Total dairy foods were grouped as followed:

• cheese
• yoghurt and dairy desserts
• cream and ice-cream

Participants were asked how frequently they consumed such foods, with six possible responses:

• never
• seldom
• once a week
• 2-3 times a week
• 5-6 times a week
• once or more a day

Participants were also asked which type of milk they consumed – full fat, reduced fat or skimmed.

The researchers used validated statistical methods to analyse the relationship between mental performance scores and dairy intake. They adjusted their results for other factors that might affect the results, including age, education, smoking and alcohol.

 

What were the basic results?

The researchers report that participants who consumed dairy products at least once a day had “significantly higher scores on multiple domains of cognitive function� compared with those who never or rarely consumed dairy foods. In addition, those who reported eating dairy foods between two and four times a week performed significantly better on some of the tests than those who ate dairy foods once a week. The association between greater dairy food consumption and mental performance remained significant after adjusting for a number of risk factors. There was no significant association, however, between intake of specific categories of dairy foods (such as milk, cheese or yoghurt) and results of the tests.

 

How did the researchers interpret the results?

The researchers say their results support an association between high dairy food consumption and cognitive function. Although little is known about how dairy foods might influence mental functioning, they say that one possibility is that dairy food consumption may be beneficial for mental functioning through its “favourable effect� on cardiovascular risk factors such as obesity.

 

Conclusion

Contrary to the headlines, this study does not show that dairy food consumption has benefits for mental functioning. All it can do is provide a “snapshot� of a group of people’s dairy consumption and their mental functioning at one point in time. Some limitations are that:

• It relied on people self-reporting their dairy intake, which introduces the possibility of error.
• It is possible that many other factors (known as confounders) might have affected the results, including exercise habits, alcohol and stress levels, although researchers tried to adjust their findings for some of these.
• As the authors acknowledge, the dietary questionnaire did not specify size of portions or servings, which undermines the accuracy of estimated intakes.

Dairy products contain many nutrients that are needed for good health, in particular for the development of healthy bones and teeth. However, they are also high in saturated fat, which is associated with heart disease and obesity. At present there is no good evidence that dairy foods are especially beneficial for brain functioning.

Find out how dairy fits into a healthy diet using the Eatwell Plate.

Links To The Headlines

The white stuff: Drinking just one glass of milk a day could boost your brain power. Daily Mail, January 31 2012

Links To Science

Crichton GE, Elias MF, Doreb GA, Robbins MA. Relation between dairy food intake and cognitive function: The Maine-Syracuse Longitudinal Study. International Dairy Journal 2012:22;15-23

A “sunny break may be alternative to IVF,� the Daily Mail has reported. The newspaper said that sunlight can increase levels of vitamin D, which balances sex hormones in women and improves sperm count in men. It added that a study found some couples "may be undergoing unnecessary and costly fertility treatment when spending time in the sun could be the answer".

The news is based on a systematic review of any kind of scientific study that was related to vitamin D and fertility. The review found that there was a lack of human studies, particularly controlled human studies, which had looked at the effect of vitamin D on fertility. This review therefore mostly looked at animal laboratory and observational studies and it is not clear what the implications of this basic research is for infertile couples without further follow up with human studies.

The basic research showed that vitamin D plays a role in biological processes in sperm and ovary cells and may affect levels of sex hormones.

There are many reasons why a couple may be infertile. The cause of a couple’s infertility is usually determined prior to IVF or other fertility treatments. It is not possible to say, as the Daily Mail has suggested, whether spending time in the sun would prevent the need for fertility treatments, without assessing the cause.

 

Where did the story come from?

The study was carried out by researchers from The Medical University of Graz in Austria and was funded by two Austrian governmental agencies and the Styrian Business Promotion Agency 

It was published in the peer-reviewed medical journal the European Journal of Endocrinology.

The Daily Mail accurately reported some of the findings of this review but overemphasised the relevance to infertile couples. Without human controlled trials it is not possible to say whether spending time in the sun could reduce the need for fertility treatments, though the advice does present an attractive option.

 

What kind of research was this?

This was a systematic review that looked at all of the available scientific papers on vitamin D and fertility. Many factors can cause infertility. The researchers said that in approximately 30 to 40% of infertile couples the underlying cause is problems with the men’s sperm. In women, there are various factors that can mean that they do not release an egg or make it difficult for a fertilised egg to attach to and grow in the uterus. The researchers say that one major cause of female infertility is polycystic ovary syndrome (PCOS), a condition that affects their sex hormones.

This systematic review took a broad sweep approach to look at the evidence for a link between vitamin D and any aspect of fertility. Although systematic reviews are a good way of comprehensively looking at all of the evidence in an area, there can sometimes be limitations to pooling data if the included studies differ in design. In this systematic review, the researchers included both human and animal studies and care has to be taken in reporting which of the included studies have relevance to humans.

 

What did the research involve?

The researchers looked in one medical database for English language publications up to October 2011. They searched the terms and phrases: vitamin D, fertility, vitamin D and reproduction, vitamin D and PCOS. They also searched for alternative names for vitamin D and looked at the reference lists from the studies their search had found.

In most systematic reviews, the researchers listed their criteria for including or excluding studies. They may, for example, only include some study designs and not others. However, in this review, the researchers did not say how they decided to include studies. The researchers said that they did not find many human studies and have included animal and laboratory studies that can give information about the basic biology of vitamin D but do not tell us whether vitamin D can help infertile couples.

 

What were the basic results?

The researchers said studies have shown that:

• The vitamin D receptor has been found in human testes and sperm in men, and in the ovaries and placenta in women.
• Removing the vitamin D receptor in genetically modified mice leads to decreased sperm count and motility and affects the structure of the testes. In female genetically modified mice, removing this receptor causes changes to the structure of the ovaries and uterus.
• One study reported that in high latitude countries there is a large difference in the amount sunlight in the summer and winter. Also there are decreased conception rates in the winter months and peak conception rates in the summer months.
• One study suggested that women’s ovulation rates and the receptiveness of their uterus for a fertilised egg is reduced during long dark winters in high latitude countries.
• Studies investigating the association of vitamin D status with IVF had inconsistent results. One study found no association; one found that higher vitamin D levels had a positive effect, and one found that women with sufficient vitamin D had poorer outcomes then women with insufficient vitamin D.
• Three studies found a correlation between low vitamin D and some, but not all of the symptoms of PCOS.
• Studies looking at the effects of vitamin D on fertility in healthy women are sparse. One study of 101 young women found that higher vitamin D levels were associated with lower sex hormone levels. A small study found that a course of vitamin D supplementation had no statistically significant effect on sex hormone levels.
• One study of 300 men found that there was an association between higher vitamin D levels and higher sperm motility, but another study found no association between vitamin D and sperm count and the proportions of normal sperm.
• One study of 2299 men found an association between vitamin D levels and male sex hormone levels.

 

How did the researchers interpret the results?

The researchers said that evidence based largely on animal work and observation studies rather than controlled trials has suggested that vitamin D deficiency might be important for hormone disturbances including fertility in women as well as men. They say that these findings deserve further investigation.

 

Conclusion

This systematic review looked for all available studies prior to October 2011 that had looked at fertility and vitamin D. Besides this very broad search the review included animal, laboratory and observational studies, which means that it is difficult to draw conclusions on the implications of this data for people. The researchers noted that there was a real lack of human controlled studies. As a result, it is not possible to say that fertility problems in men and women could be helped by vitamin D supplementation, increasing vitamin D through diet or spending time in the sun.

Vitamin D and its human effects is currently a topic of immense interest to the public and to policy makers. This research looked at another angle, that of fertility, and is useful in giving a broad overview of the basic biology of vitamin D and a range of biological processes involved in infertility. It highlighted where there has been a lack of studies and where more work could be done. Future assessments into the role of vitamin D in fertility should as a minimum involve controlled human trials.

Links To The Headlines

Sunny break may be alternative to IVF: How the sunshine vitamin can help boost fertility. Daily Mail, January 30 2012

Links To Science

Lerchbaum E, Obermayer-Pietsch BM. Vitamin D and fertility - a systematic review. European Journal of Endocrinology. Published online January 24 2012

Many newspapers and TV stations have reported that medical regulators have launched an investigation into a type of hip replacement called a metal-on-metal (MoM) device (DePuy ASR hip replacement implant). The concern is that as the hip replacements wear down, metal particles can be released from the artificial hip, react with the soft tissue (such as muscle and ligaments) surrounding the joint and enter the bloodstream. In 2010, the UK regulator, the Medicines and Healthcare products Regulatory Agency (MHRA) issued a product recall for DePuy ASR, a brand of MoM artificial hip. This meant that surgeons were told not to implant DePuy ASR hip replacements and return any unused implants to the manufacturer.

The MHRA has urged surgeons to tell all patients that had received these DePuy ASR hip replacements about the recall, and to schedule them for annual follow-up visits. If the person who had a DePuy ASR hip replacement implant experiences pain, the surgeons should consider measuring the level of metals in their blood and should examine the soft tissue to see if reactions have occurred. If necessary, removal and replacement of the implant should be considered.

The Sunday Telegraph has brought this story to the public attention again because of what it says are subsequent developments. The Telegraph claims that the risk from the devices is greater than previously thought, with greater failure rates. The Telegraph says that the MHRA is drawing up a new alert for anyone with any type of metal-on-metal hip replacement. Channel 4 News reported that around 30,000 people in Britain have received MoM hip replacements.

A statement about the hip implants from the MHRA, issued on January 30 2012, said: “The majority of people with metal on metal hip replacements are at low risk of developing any serious problems. We are continuing to closely monitor all evidence. This needs more analysis before any conclusions can be drawn and further advice given. We have already taken prompt action to investigate safety concerns and have provided advice on patient management to relevant healthcare professionals.�.

Medical devices, like medicines, are regulated but are coming under more scrutiny, from both the regulators and the media following widespread concerns over the emergence of faults with illegally made PIP breast implants. Find out the latest NHS information on PIP breast implants.

 

What types of hip replacements are there?

In the UK, approximately 70,000 hip replacements are performed each year. In a total hip replacement operation an artificial ball is attached to the top of the leg bone and an artificial socket to the hip bone. The socket can be made out of plastic or ceramic, while the ball is metal. The ball is attached to a shaft, which is placed in the hollow of the leg bone (femur). Some people do not need a total hip replacement, but have a hip resurfacing operation. This has the advantage of removing less of the person’s own bone. The joint surfaces are replaced with metal inserts that cover the surfaces of the hip but do not extend down the inside or hollow of the leg bone. The metal mixtures used in hip replacements contain the metals chromium and cobalt.

 

What are the risks of problems following a metal-on-metal hip replacement?

When hip resurfacing was initially introduced, metal-on-metal (MoM) replacements were popular, especially with younger, active patients. An article by two orthopaedic surgeons working in Britain and published in the British Medical Journal in 2011 said that they were used in 10% of hip operations between 2006 and 2009, and 50% of all hip replacements in people younger than 50 years. However, problems with the metal resurfacing included raised chromium and cobalt in the blood, loosening of the joint, hip fracture and soft tissue reactions around the hip. It reported that problems with metal on metal hip replacements could include reactions to metal debris and associated pain, swelling, loss of movement and limping.

In March 2011, delegates at the British Hip Society annual conference discussed MoM hip replacements. Units in Belfast, Southampton, Cardiff and Stockton-on-Tees that had researched the outcomes for people who had these devices fitted over the short- to mid-term, said that a high proportion of MoM devices from other manufacturers may also be showing similar results to the withdrawn DePuy device. They found that, overall, the MoM devices showed a higher than anticipated early failure rate (most hip replacements last about 20-30 years). They found that 49% of people who had been fitted with the DePuy device needed to have it replaced by six years and between 12 and 15% who had other metal-on-metal hip replacements needed these to be replaced by five years. They said that the patients whose replacements failed tended to come to the doctors when they experienced pain. X-rays showed some patients had loosening of the joint, and some patients had raised levels of cobalt and chromium in their blood.

The inclusion of the word “poisoned� in some newspapers is likely to be wrong. Metal from the hip replacements can enter the bloodstream, but the levels of cobalt and chromium found give an indication of the wear to the hip replacement. No evidence for damage other than local tissue damage was presented. The MHRA’s advice is to monitor the level of chromium and cobalt to see if a patient requires further follow-up.

 

What is the advice for people who have had a MoM hip replacement?

The MHRA has not issued new guidance as yet. However, the report from the British Hip Society annual conference says that they believe that the existing advice from the MHRA still applies. This means that people who have been treated with a MoM hip replacement should be followed up regularly for five years and probably for the life of the implant. People with the withdrawn MoM hip replacements who experience pain should have this thoroughly investigated. Following the withdrawal of the DePuy device, and the MHRA guidance, the British Hip Society and the British Orthopaedic Association said:

• Everyone with a hip replacement that has been withdrawn should be informed and told that they will be under close clinical follow-up.
• Some form of follow-up should be carried out at least annually and patients should be given contact information so that they can be reviewed quickly if they have pain or lose function in their hip.
• Patients should be followed for the life of the implant until more data are available. If someone with a withdrawn MoM hip replacement experiences no pain or loss of function, no further investigations are required apart from standard follow-up.
• If a person with a withdrawn MoM hip replacement reports that they are in pain, the cause of the pain should be further investigated. Blood cobalt and chromium levels should be measured to indicate how much the device has worn, but there is no evidence that the implant must be replaced above a certain metal concentration.
• Treatment decisions should be confirmed with a second experienced “revisionâ€� surgeon.

People who have had a hip replacement, who are concerned, should contact their orthopaedic surgeon or GP. They should be given records of the type of hip replacement they had and receive the follow-up, if any, that is required.

Links To The Headlines

Health warning over hip implants. The Daily Telegraph, January 28 2012

MHRA investigation over 'toxic' hip replacements. Channel 4 News, January 29 2012

MHRA launches investigation after hip replacement 'poisoning' claims. Metro, January 29 2012

Poison fears sparked over hips. The Sun, January 29 2012

Poison scare for 40,000 from faulty hip implants. Daily Express, January 29 2012

Watchdog starts inquiry into hip replacements. The Guardian, January 29 2012

Fears over hip replacement poisoning. Sky News, January 29 2012

Poisonous hip implants 'putting thousands of British patients at risk' as medical watchdog launches investigation. Daily Mail, January 30 2012 

Men are far more likely to have the sexually transmitted human papillomavirus (HPV) in their mouths than women, the Daily Mail has reported. The Mail has outlined research into the prevalence of HPV, which is a risk factor mouth cancer and other cancers. Researchers found that HPV was more commonly found in people who engaged in all kinds of sexual activity – including vaginal, anal and oral. The Mail reports that the researchers suggest that HPV vaccination for men needs investigating to see whether it could help stop oral HPV and, potentially, oral cancer.

Mouth cancer has risen more than 20% in the past 30 years. Tobacco use and prolonged, heavy alcohol drinking are the biggest risk factors, but the presence of oral HPV is also a clear risk factor for the disease.

The latest research set out to estimate the proportion of people infected with oral HPV in the United States, and any factors associated with infection. It found that approximately 7% of the US population aged 14 to 69 years were infected with this virus, and that men were more likely to be infected than women.

This study shows a marked difference in oral HPV infection between men and women in the US, but does not necessarily reflect how many people in the UK are infected. There are many different types of HPV, and not everyone who is infected will go on to develop cancer.

HPV is known to cause cervical cancer, and a vaccine campaign for girls aims to reduce its prevalence among women, and so reduce the number of cervical cancers. It remains unclear whether vaccinating men would have an effect on the presence of oral HPV or reduce the number of cancers.

 

Where did the story come from?

The study was carried out by researchers from Ohio State University, the US National Cancer Institute and a US company called Information Management Services. The research was funded by Ohio State University, the US National Cancer Institute, John and Nina Cassils and the pharmaceutical company Merck. Merck is the manufacturer of Gardasil, the cervical cancer jab that targets several strains of HPV, including type 16, which is most commonly associated with oral cancer.

The study was published in the peer-reviewed Journal of the American Medical Association.

This research was covered appropriately in the media, with the Daily Mail emphasising that the prevalence estimate was drawn from a US population, and pointing out that not all individuals infected with oral HPV will go on to develop oral cancer. The BBC was careful to point out that it is not known if the existing vaccines against HPV used for preventing cervical cancer are effective against oral HPV infection and that vaccination cannot be recommended for the primary prevention of oropharyngeal cancer.

 

What kind of research was this?

This was a cross-sectional study that examined the number of people aged 14 to 69 infected with oral HPV in the United States.

Cross-sectional studies are a useful way to generate estimates of the number of cases in a population. However, they only collect information at one point in time, and cannot tell us why things are related, or how things change over time. This study provides a snapshot of the number of infections in one time period (between 2009 and 2010), but it does not attempt to link these numbers to the risk of developing oral cancer.

Background information supplied by the researchers suggests that the number of cases of oral cancer has increased over the past 30 years in several countries, and HPV has been directly implicated as the underlying cause.

 

What did the research involve?

Researchers recruited a sample of individuals that was intended to be representative of the US population. They conducted interviews and a physical examination. During the interview, participants provided information about:

• sociodemographic factors – such as age, sex, education, socioeconomic status, sexual orientation and marital status
• substance use – including tobacco, alcohol and marijuana
• sexual behaviour – including ever having had sex, ever having performed oral sex, age at first sex, number of sexual partners and history of sexually transmitted infection

During the physical examination samples of cells were taken from the inside of the mouth. These samples were sent to a laboratory where researchers isolated DNA from the cells to determine whether the individual was infected with oral HPV and, if so, to identify the virus type. They tested for 37 HPV types, of which 18 were ‘high-risk’ DNA types.

The researchers then analysed the data, arriving at overall estimates of the number of infections in the US population. They also conducted an analysis that accounted for sociodemographic and behavioural factors.

 

What were the basic results?

There were 5,579 participants in the beginning of the study. Of these 5,501 (98.6%) were included in the analysis. The researchers found that overall:

• 6.9% of participants were infected with HPV (95% confidence interval (CI) 5.7% to 8.3%)
• 3.7% of participants were infected with a type of HPV classified as having a high risk of causing cancer (95% CI 3.0% to 4.6%)
• 3.1% of participants were infected with a low-cancer-risk type of HPV (95% CI 2.5% to 3.9%)
• the most prevalent type of virus detected was HPV-16 (1.0%, 95% CI 0.7% to 1.3%)

When the researchers accounted for sociodemographic and behavioural factors in their analysis, they found that the following variables were independently associated with oral HPV infection:

• Age: infections peaked at two distinct age groups - in those aged 30 to 34, and again in those aged 60 to 64. This pattern was stronger for men than women.
• Sex: men had more than twice the number of infections as women (10.1% male versus 3.6% female; prevalence ratio (PR) 2.33, 95% CI 1.66 to 3.26). When looking at the most common HPV type (HPV-16) this increased to a nearly fivefold difference (1.6% male versus 0.3% female; PR 5.41, 95% CI 2.12 to 13.83).
• Lifetime number of sexual partners: those with two or more partners had significantly more infections than those who had no sexual partners. The prevalence of infection increased with increasing numbers of lifetime partners.
• Current smoking intensity: those who smoked 10 or more cigarettes a day had significantly more infections than those who had never smoked or who no longer smoked. This association was stronger for women than for men.

Ethnicity, marital status and alcohol and marijuana use were not independently associated with oral HPV infection.

 

How did the researchers interpret the results?

The researchers concluded that approximately 7% of the US population between the ages of 14 and 69 were infected with oral HPV. They say that this is significantly lower than infection with genital HPV.

 

Conclusion

This was a relatively large cross-sectional study that estimated the number of oral HPV infections in the US among 14 to 69 year olds. These estimates cannot be directly generalised to the UK.

The researchers say that their data provide evidence that oral HPV infection is mainly sexually transmitted. This is because infection was uncommon among participants with no previous sexual partners, but was up to eight times higher among those with previous partners, and increased significantly as the number of partners increased. The researchers do point out, however, that their study did not collect information on possible non-sexual transmission methods.

While policy decisions regarding HPV infection generally focus on genital HPV among females, this research demonstrated that, at least in the US, men are more likely to be infected with oral HPV. As high-risk types of oral HPV have been shown to cause mouth cancer, this research may open up discussions on the need to address these risks. Options for reducing the risk of infection include targeting modifiable behaviours, such as smoking and sexual behaviour. Whether current vaccines against HPV can prevent oral cancer is unknown and this research does not provide any evidence as to how effective any vaccine might be.

All in all, this was a well conducted cross-sectional study that estimated the prevalence of oral HPV infections in the United States. However, it does not provide any information on the number of participants who went on to develop oral cancer. It is important to remember that there are many different types of HPV, and not everyone who is infected will go on to develop cancer. This study cannot tell us the rates of oral HPV infection in the United Kingdom, but may provide information on risk factors for infection that apply to populations outside the US.

Links To The Headlines

More men 'have oral cancer virus'. BBC News, January 27 2012

More than 16 million Americans have oral HPV. Daily Mail, January 26 2012

Links To Science

Gillison ML, Broutian T, Pickard RKL, et al. Prevalence of oral HPV infection in the United States, 2009-2010. Journal of the American Medical Association. Published online January 26 2012