An Australian scientist has written a provocative opinion piece which looks at the impact of grazing on bushfires, as well as the problem of feral flora and fauna in Australia. It suggests considering all potential solutions, including the introduction of wild elephants to keep introduced grasses under control.

Below the author explains his intentions while other experts in the field respond to the piece. 

Feel free to use these quotes in your stories. If you would like to receive a copy of the embargoed paper or to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

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David Bowman, author of the Comment piece, is Professor of Environmental Change Biology at the School for Plant Science at the University of Tasmania (author comment)

“This piece is intentionally challenging. We are going to be driven, whether we like it or not, to think outside the square, because current approaches to land management in many of our landscape settings - in protected areas and unprotected areas, productive landscapes and outback Australia - are not working. Or the approaches we’ve got are not sustainable. We’ve got some big challenges ahead, that’s the point, and we have to be honest about it. Humans are a very important part of Australian ecology.

What I’m saying can be completely misconstrued and that will be sad if it’s put into a polarising debate. What I’m saying is that these challenges open up really fresh thinking which is what we need.”

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Dr Aaron Petty is from the Research Institute of the Environment and Livelihoods at Charles Darwin University, Northern Territory

“I will speak mostly about Gamba grass, as it is the major focus of this piece and his only rationale for why elephants are needed. What Professor Bowman suggests is that “the usual approaches…are not working”, but the fact is the usual approaches have not even been tried effectively. As far as I know Gamba Grass has not yet been declared a weed of national significance, although that status is pending. In the Northern Territory, Gamba Grass was only recently, in 2008, declared a controlled weed and its sale as hay banned. This came only after the tireless work of a dedicated and small group fighting against intense pressure and lobbying from the cattle industry.

Prof. Bowman is quite correct in his concern about Gamba Grass as it has the potential to irreversibly alter the structure of our northern savannas. He is also correct that only chemical treatment and physical clearing of the landscape can control it. However, the proportion of the landscape at present invaded by Gamba grass is large, but a tiny proportion of our northern savannas. Containing the spread of Gamba grass will be costly, but tiny compared to, say, recent money applied to prop up the car industry.

Likewise, Prof. Bowman claims that efforts to control buffalo are ineffectual. Yet this is not so, the Brucellosis and Tuberculosis Eradication Campaign (BTEC) was immensely successful in eradicating buffalo from Kakadu National Park, rapidly repairing wetlands that were severely damaged from buffalo overpopulation. So, in short, we are not out of ideas, we merely lack the political will to implement the steps needed to control our environmental problems.”

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Professor Richard Hobbs is an Australian Laureate Fellow with the School of Plant Biology at The University of Western Australia

“Dave Bowman has rightly suggested that we need to consider new and varied approaches to tackling Australia’s ecological management conundrums. He points out that existing approaches have largely failed to make an impact on the massive problems of wildfires, feral animals, weeds and so on. I agree that we need to think broadly about alternatives - but we need to do this sensibly and with an eye on the lessons of the past.

Dave provides a wide spectrum of potential strategies, some of which have more merit than others. The Nature article contains some interesting contradictions: in one sentence Dave highlights the importance of controlling the ad hoc release of non-native animals and plants, but in the next advocates the introduction of predators to control feral animals and herbivores to graze the flammable grasses.

Does bringing elephants and komodo dragons into Australia make ecological sense, given the unforeseen circumstances generated by earlier introductions (usually carried out with the best of intentions)?  Species introduced to solve one ecological problem frequently end up causing more and often worse problems themselves. The Nature article mentions fire in both the north and the south of Australia but doesn’t differentiate between the different systems and factors at play. Elephants are unlikely to make any difference to the occurrence of forest fires in Victoria, even supposing Victorians were happy to have elephants running around their state, but they do have the potential to wreak ecological havoc in any ecosystem they are introduced to.

Maybe we need to come to terms with the fact that some of our ecosystems may remain changed because of the species we’ve already introduced, rather than introducing more in the hope that they can fix things for us.

In amongst the more outlandish suggestions lurk ideas that are less risky and can work - indeed some are already being implemented, such as the reinstatement of Aboriginal fire management in the north. Programs such as the Australian Wildlife Conservancy’s fire management in the Kimberley are having great success. These in themselves are radical innovations, but ones based on sound ecological understanding.

While I agree that the full spectrum of options needs to be canvassed, discussion of bringing elephants to Australia is probably more of a useful ploy to get people’s attention than a serious option for the future.”

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Dr Ricky Spencer is a Senior Lecturer with the Native and Pest Animal Unit at the University of Western Sydney

“Professor Bowman is obviously trying to raise some very important issues that we face in Australia; the problem is that his comments are careless given recent proposals for the establishment of game reserves in NSW and introduction of new potential feral animals into these reserves. His comments about introducing more dingoes to control other feral animals are also irresponsible because the science behind meso-predator release or suppression is in its infancy and at best correlative. If we did go down the road of introducing elephants to Australia, we had better develop the technology to clone saber-tooth tigers to eventually control the elephants.”

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Professor Patricia Werner is a Visiting Fellow at the The Australian National University’s Fenner School of Environment and Society

“Professor Bowman is the same fellow that made the headlines in the Northern Territory News about five years ago when he advocated introducing African large grazing mammals to rid the place of introduced grasses (i.e. gamba grass, mentioned in this article). So, this is not new.

As for elephants and rhinoceroses, these are browsers, not grazers (as are various types of antelope, cattle, etc.). They eat not only grass but leaves, twigs, fruits, roots they dig up, and even bark. An adult elephant can eat 150 - 300 kg of vegetation a day, only about half of which is grass. They digest only about 40 per cent of what they eat, so have to rely on volume to get enough food to sustain themselves.

There are countless studies in Africa showing that when elephants are removed from an area, tree cover increases. That is, elephants reduce/keep down trees, eating juvenile trees, stripping bark, etc. Are we in Australia prepared to try yet another landscape-scale “experiment” as we did with foxes, rabbits, etc, and merely hope that the elephants don’t find our native Australian trees tasty?  Can we somehow command them to eat only introduced African grasses?  And would we mind seeing our wooded savannas turn to a more grassy-savanna such as those that dominate in Africa - match any rainfall area to ours and you will find less woody cover than we have.”

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Dr Don Driscoll is a Fellow at The Australian National University’s Fenner School of Environment and Society

“Professor Bowman makes two critical points in his paper with which I agree. Australian ecosystems are in a desperate state of degradation due to invasive plants and animals. Invasive species have wiped out much of Australia’s natural heritage, they continue to destroy what we have left, and international trade combined with pressures to increase agricultural productivity worsen the problem. The second critical point that Bowman makes is that, because of this ongoing environmental catastrophe, we need to put all of the management options on the table to try to find ways of reducing the rate at which our biodiversity succumbs to the impacts of invasive alien species.

We should therefore consider introducing elephants and rhinoceros to Australia. We should also reconsider widely implemented practices such as culling dingos or burning forests to reduce fuels in southern Australia as an asset-protection measure. Introducing elephants to Australia would likely be rather quickly rejected as a method for controlling invasive gamba grass. The cost of fencing, the effectiveness of controlling the problem (think cane-toads and cane-beetles), and the risk of adverse impacts (e.g. elephants have a tendency to push trees down) would, I suspect, quickly render the elephant option less attractive than alternative actions for controlling gamba grass.

On the other hand, evidence is mounting that dingos have enormous environmental benefits with little increased risk to the cattle industry, and wide-spread fuel reduction in forests has negative environmental and water quality impacts, while having little influence over the risk of house loss in wildfires. It is crucial to consider all of the management options for dealing with invasive species (even ideas that might seem crazy at first), and it is just as crucial to consider their cost and the evidence of the kinds of impacts that each option will have on a range of societal objectives.”

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*Bring elephants to Australia?, Bowman., Nature, Vol 482, 2012

In a comment piece, international scientists argue that added sweeteners pose dangers to health that justify controlling them like alcohol. Here an Australian expert puts the arguments into context for Australian readers.

Feel free to use these quotes in your stories.  Any further comments will be posted here. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

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Prof Kerin O’Dea is Director of the Sansom Institute for Health Research in the Division of Health Sciences at the University of South Australia

“I agree with Lustig et al that added sugars in western diets are problematic.  I am quite comfortable with dietary sugars if they come from whole foods (i.e. fresh fruit and some vegetables) – as the sugar is diluted with water, fibre and a range of other nutrients.

With added sugars (in many drinks and an ever larger number of processed foods) the sweeteners are extra calories.  Sucrose is a disaccharide comprised of one molecule of glucose and one molecule of fructose. Glucose is an important energy source for most cells in the body. In contrast, fructose is taken up primarily by the liver  – and if you are over-consuming energy then it is converted efficiently to fat.  If you do not over-consume energy then fructose is not a problem.  However, added sugars are mostly in energy-dense processed foods or added to drinks, and frequently are over-consumed.

Much used to be made of the fact the fructose does not elicit significant insulin or leptin responses (low GI)  – however, it is now recognized that these two hormones are important satiety signals for the brain. Because of this I argue that fructose ‘gets under the satiety radar’.”

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Prof Leonie Segal is Foundation Chair of the Health Economics & Social Policy Group at the University of SA, with an international profile in the economics of nutrition. She was a member of the Ministers Preventative Health Taskforce

“A focus on added sugar is most timely, with increasing evidence of its negative health effects.

The public health arguments for intervening are indeed strong, with perhaps the most important consideration, not highlighted by the authors, the imperative of governments to protect vulnerable members of society, especially where the capacity for well-informed decision making is limited or non-existent.

Because eating habits and taste tend to be influenced by what we eat as infants and young children, an unhealthy habituation or addiction to sugar, which influences lifetime health, can be established from a very young age when the ability and capacity to make informed eating choices are simply unavailable. This provides a strong case for governments to intervene to encourage healthy food choices, by children and thus families. And as the authors argue excess sugar is a crucial aspect of current poor food choices and thus an important focus of such policies.

While at its extreme alcohol may have more damaging effects than sugar, excessive consumption of sugar is considerably more prevalent than excessive alcohol consumption, part of the reason why population level strategies make sense.”

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Prof Peter Clifton is Head of Nutritional Interventions at Baker IDI Heart and Diabetes Institute

“Alcohol toxicity is not just metabolic  – it causes violence and road deaths and sugar in any of its forms cannot compete with this statistic. Almost all of the evidence against sugar is epidemiological  – that is association not necessarily causation.

In intervention studies with fructose, up to 10% of calories show no metabolic effects while a few studies with fructose at 25% of energy do show a modest increase in triglycerides but not high enough to cause pancreatitis.

There are no controlled interventions that show feeding fructose or sucrose causes hypertension and none that show that a controlled reduction in sugar alone reduces blood pressure. However, there is evidence to show that increasing sugar-sweetened beverage intake does cause modest weight gain as the liquid calories are not compensated by a reduction in calories from other foods.

Sugar is just another form of over-consumed calories  – easily available and very palatable but no more metabolically deadly than starch or fat calories and certainly not equivalent to alcohol.”

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Dr Alan Barclay is an accredited practicing dietitian and nutritionist, Chief Scientific Officer for the Glycemic Index Foundation Ltd and head of research at the Australian Diabetes Foundation

“This commentary is a provocative piece intended to encourage debate. Many of the statements simply do not apply to Australia and on certain issues there is little evidence to support their views. ‘Sugar’ is not the issue, it is far more complicated than that.

The authors state that over the past 50 years, consumption of sugar has tripled worldwide. However, in Australia sugar consumption has dropped 23% since 1980. Despite this, during that time cases of overweight or obese people have doubled, whilst diabetes has at least tripled.

The authors believe that attention should be turned to ‘added sugar’, which they have defined as any sweetener containing the molecule fructose that is added to food in processing. The authors suggest that fructose can trigger processes that lead to chronic diseases including liver toxicity, however one would need to eat at least 135g, or about 32 teaspoons, of pure added fructose per day on top of what one already eats. Only one per cent of Americans eat more than 100g per day of total fructose. The only disease proven to be related to excess frequent sugar consumption is tooth decay  – a significant problem  – but even then, refined starch is at least equally as cariogenic but is rarely acknowledged as a problem.

Lustig and his colleagues claim that sugar should be regulated like alcohol because it is unavoidable, toxic, has potential for abuse and has a negative impact on society. However, it is certainly not unavoidable, it is only ‘toxic’ in unrealistic amounts and to suggest that consuming sugar is a form of abuse is one of the worst cases of puritanism that I have seen in a while. It’s worth noting that soft drinks and other non-core ‘party’ foods are already taxed (GST) in Australia.

Just like anything else, sugar should only be eaten in moderation. As we continue our research we are finding out more and more about the importance of refined starch and specific fatty acids and the average Australian can do a lot to improve their diet, but casting sugar as the ultimate villain and calling for regulation is misleading, unfounded and unnecessary.”

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[*The toxic truth about sugar, A Comment piece, Lustig et al., Nature, 2012 (482), pp27-29]

Feel free to use these quotes in your stories.  Any further comments will be posted here. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

* ‘Embryonic stem cell trials for macular degeneration: a preliminary report’ by Steven Schwartz et al. is published in The Lancet, 23^rd January 2012.

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Professor Martin Pera is Chair of Stem Cell Science at the University of Melbourne and Program Leader of Stem Cells Australia

“The report in the Lancet today from scientists at UCLA and Advanced Cell Technologies provides hope for patients suffering from dry macular degeneration, a very common cause of blindness. Although the work is preliminary, the study shows that replacement of retinal pigment epithelial cells (the cell type that is lost in this disease) by grafts derived from human embryonic stem cells appears to be safe, and may lead to an improvement in vision. This landmark study is the first published account of a human trial of embryonic stem cell based therapy. The authors described results from only two patients, and it is possible that the improvements that they observed may be related to other factors apart from the graft itself. Nonetheless the early findings are most encouraging.

Macular degeneration is a very promising target for stem cell therapies, because the required cell type can be efficiently produced from embryonic stem cell cultures, and because the eye is easily accessible for surgery and for monitoring the progress of the graft. Centres in California, the United Kingdom, and elsewhere are also progressing towards clinical trials of stem cell therapies in this disease. It will soon be clear whether these preliminary results published today are a harbinger of a new era in cell therapy for this devastating medical condition.”

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Dr Bernie Tuch is Director of the New South Wales Stem Cell Network

“This is a wonderful concept which should be strongly supported. It provides hope that something positive can be done about it for people who are losing their vision.”

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Dr Andrew Laslett is Research Group Leader, Stem Cells, CSIRO Materials Science & Engineering, Victoria

“This report allows cautious optimism that cells derived from human embryonic stem cells may be useful for the treatment of a common cause of blindness, namely macular degeneration. It is very early days and only two patients have been reported on to date but this first ever peer-reviewed report of a human embryonic stem cell-based human clinical trial demonstrated no adverse side effects and both patients showed mild improvement in their vision. The long term hope, based on these results, is that earlier intervention may lead to greater improvements in visual acuity for people with macular degeneration and that these improvements will persist and be safe.”

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Associate Professor Kuldip Sidhu is Director of the Stem Cell Lab and Chair of Stem Cell Biology at the University of New South Wales

“This is an another significant proof of principle that hESC-derived cells have potential in therapeutics if produced carefully avoiding residual hESCs that may cause teratoma - a major concern so far in the use of such cells. In this study a pure population of RPE derived from hESCs were transplanted into the patients eyes diagnosed with macula degeneration. Although only the phase I trials on two patients were carried out and the short term follow up for four months shows cell survival and apparently no adverse effects or tumours formation - a significant way forward in the clinical use of such cells in future. It is too early to conclude that clinical outcome is due to transplanted cells, it may simply be a trophic effects as also pointed out by the authors in this publication. A further long term follow up on these patients is essential to rule out adverse affects if any. Apparently the protocol developed for obtaining RPE from hESCs in Dr Robert’s lab so far involves the use of feeder cells from animals that can be avoided in the future as feeder-free systems are evolving rapidly.”

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Expert response from UK scientists

Compiled by our colleagues at the UK Science Media Centre

Expert reaction to preliminary data on stem cell trial for macular degeneration, as published in The Lancet*

Professor Daniel Brison, Co-Director of the North West Embryonic Stem Cell Centre, Manchester, said:

“This is a very exciting moment for embryonic stem cell therapies.  This is the first peer-reviewed scientific report showing that cells derived from human ES cells can be transplanted safely into a patient with no sign of complications.  Although the study is limited to safety considerations, very small in scope, and at a very early stage, this is nonetheless a ground breaking moment for embryonic stem cell therapies.  It is also very significant for the UK that the second trial of these therapies has now begun in London, only 4 months behind the US trial.  These trials have used human ES cells created at research grade and this was possible as they were transplanted into the eye which is a very localised site in the body.  In order to realise the full potential of ES cell therapies in the future, it will be very important to use the new generation of clinical grade ES cells now being produced in the UK.”

Professor Chris Mason, Chair of Regenerative Medicine Bioprocessing, University College London, said:

“The preliminary data on the two US patients treated using human embryonic stem cell-based therapies in June 2011 is highly encouraging, but is only the start of gathering the necessary safety data before it is possible to test if the therapy will have an impact on patients’ vision. Overall the process of testing for safety and efficacy is likely to take a minimum of 5-10 years before the potential therapy could enter routine clinical practice.

“It is not surprising that the first European human embryonic stem cell-based therapy was carried out in London, given that the UK is a world leader in cell therapy.

“The safety of embryonic stem cell-based therapies in patients is now slowly starting to emerge with both Geron data for spinal cord injury and now ACT for retinal disease. It is still a long way to go before we will have the answer as to whether embryonic stem cell-based therapies will be safe and efficacious, but progress continues to be made towards striving for the ultimate goal of life-changing therapies for patients and their carers.”

Dr Dusko Ilic, Senior Lecturer in Stem Cell Science, Kings College London, said:

“The most important thing is that Robert Lanza and his team at the Advanced Cell Technology get across a message to the media and the public that ongoing clinical trials for dry age-related macular degeneration and Stargardt’s disease with retinal pigment epithelium (RPE) derived from hES cells are safety trials. Even though in preclinical trials, the RPE were capable of extensive photoreceptor rescue in an animal model of retinal disease, resulting in improvement in visual performance without evidence of untoward pathology, we should keep in mind that people are not rats. The number one priority of initial clinical trial is always patient safety. If everyone expects that the blind patients will see after being treated with hES cell-derived RPE, even if the treatment ends up being safe (which is what Advanced Cell Technology are trying to determine in this trial), they risk being unnecessarily disappointed.”

Professor Peter Coffey, Director of the London Project to Cure Blindness said:

“At last seeing fruits of human embryonic stem cell research entering clinical trials. This will help determine the safety of these therapies. I am immensely happy that this has happened in the eye. And will only help those patients with, until now, blinding eye diseases. Hopefully we will be able to enter our own clinical trials using embryonic stem cell therapy soon.”

* ‘Embryonic stem cell trials for macular degeneration: a preliminary report’ by Steven Schwartz et al. is published in The Lancet today, 23^rd January 2012.

Across the world countries are having to face the serious issue of depleting water tables as the ever-increasing thirsts of agriculture and industry compete for every drop. In the US a prime example is of an aquifer that extends all the way from South Dakota to northern Texas, yet it has been lowered by nearly 50 metres. In India an aquifer that took 40,000 years to fill was emptied in just over a century, leaving the remaining water too salty and inaccessible to easily use. The problems are no different for us, we rely on underground reservoirs that have built up over thousands of years but we are draining the water far faster than it is being replaced. Amidst the controversies of the Murray-Darling Basin, coal seam gas and desalination plants, Australia is having to sit up and take notice.

An international panel of experts have come together to discuss just how bad the situation really is, what can be learned from other countries and, most importantly, what can be done.

Join the briefing to ask questions such as:

• How much water is stored and how quickly are we using it up?
• What are the contamination risks and what can we do to protect our water?
• How much does Australia’s agriculture and industry rely on groundwater? How important is it for our own drinking water?
• How do current questions over water (desalination plants, coal seam gas and the Murray Darling basin) fit into the picture and what does the future bring?
• What can we learn from other countries and what do governments need to be doing?

Follow the full presentation here |  Audio only is also available here (higher quality available on request  - 12Mb)

SPEAKERS:

• Prof Robert Glennon is Morris K. Udall Professor of Law & Public Policy at the University of Arizona, USA. He specialises in water use, is the author of Unquenchable: America’s Water Crisis and What To Do About It and was on the Advisory Board at the Centre for Comparative Water Policies and Laws, University of South Australia, Adelaide in 2011
• Prof Edward Sudicky is a Professor in the Department of Earth Sciences at the University of Waterloo, Canada and currently holds a Canada Research Chair in the field of quantitative hydrogeology. He received the O.E. Meinzer Award from the Geological Society of America in 1999, the Hydrology Award from the American Geophysical Union in 2002 and the M. King Hubbert Award from the National Ground Water Association in 2007. Professor Sudicky is a Fellow of the Royal Society of Canada, the Canadian Academy of Engineering, the American Geophysical Union and the Geological Society of America.
• Dr Leonard Konikow works at the United States Geological Survey as a research hydrologist. He has received the M. King Hubbert Science Award from USA National Groundwater Association. He was Chairman of the Hydrogeology Division of the Geological Society of America, has served on the USA National Research Council (NRC) Committee on Groundwater Modeling Assessment and was the Chairman of the American Geophysical Union’s Groundwater Committee.
• Em. Prof Ghislain de Marsily holds the position of Emeritus Professor at Pierre & Marie Curie University (UPMC) in Paris, France. He has served on numerous advisory boards including the Nuclear Waste Program of the European Commission and The Commission of Environmental Management Technology of the US National Academy of Science. He is the author of the concept of ‘Hydrogeological Natural Parks’ which suggests a protective action be taken to prevent the degradation of ground water resources.
• Prof Craig Simmons is Director of the National Centre for Groundwater Research and Training in South Australia and Professor of Hydrogeology at Flinders University, Adelaide. He is also a member of the National Water Commission’s Groundwater Technical Advisory Committee.

DATE: Mon Jan 23 2012
START TIME: 10.45am AEDT
DURATION:  48 min
VENUE: Sydney CBD (also available online).

For further information, please contact the AusSMC on 08 7120 8666 or email us.

In the ongoing debate over the benefits and harms of hormone replacement therapy, an international team of researchers has suggested that findings from the Million Women Study, which were used to establish that hormone replacement therapy (HRT) causes breast cancer, do not in fact prove a causal link.

The Million Women Study (MWS) is the largest study of its kind on the topic and has produced four reports (2003, 2004, 2006 and 2011). It was one of three major pieces of research that prompted a rethink of the long-term safety of HRT and its proponents state the findings have been replicated in many other studies.

Today’s paper is co-authored by Australian Prof Henry Burger, Emeritus Director of Prince Henry’s Institute of Medical Research, Melbourne, and Past President of the International and Australasian Menopause Societies.

Australian and UK experts respond below.

Feel free to use these quotes in your stories. Any further comments will be posted here. If you would like a copy of the paper or to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

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Dr Andrew Penman is Chief Executive Officer of Cancer Council NSW

“This research review offers no new conclusions when it comes to assessing the well-established link between hormonal replacement therapy (HRT) and breast cancer.

The reality is that the overwhelming body of global evidence confirms a link between HRT and breast cancer. Cancer Council NSW research conducted in 2008 added to this evidence with our study showing that Australian women lowered their use of hormone replacement therapy (HRT) by more than half since 2001, and this resulted in sustained reductions in the number of women developing breast cancer.

Our research reveals that HRT use dropped 55 per cent between 2001 and 2005. During the same period there was also a nine per cent drop in breast cancer rates among women aged 50 years and older, which is the equivalent of 800 fewer cases. No changes were seen in breast cancer rates in women aged under 50 years, who do not usually use HRT.

These results are consistent with other evidence that women can reduce their risk of breast cancer quickly by stopping or reducing use of HRT. So, by reducing their use of HRT, women and their doctors have had a very positive impact on breast cancer in Australia.”

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Prof Ian Fraser is Professor in Reproductive Medicine at the University of Sydney

“These authors rightly draw attention to the problems inherent in the so-called “Million Women Study”. For reasons well addressed by these authors the title of the study has inappropriately given the MWS analysis a measure of authority which size alone does not justify.

Tiny statistical differences, as promoted by the Million Women study, cannot be convincingly demonstrated by the techniques used, even though the authors attempted to ‘control’ for some of the recognized biases. It is not possible to control for all known and unknown biases in such studies, and this is well demonstrated by the authors of this latest article in the Journal of Family Planning and Reproductive Health Care. Sadly, the Million Women study did not add anything valid to the debate on HRT existing at the time it was published.

The present authors are very well respected endocrinologists and epidemiologists who have undertaken a new and critical analysis of the data presented in ‘Million Women’ and have clearly demonstrated biases, which could not be allowed for in making the conclusions which ‘Million Women’ published.

Any statistical analysis is only as good as the quality of the data analysed. Breast cancer epidemiology is so complex, and so many factors have been shown or suspected to influence incidence rates, that data analyses have to be extraordinarily comprehensive to allow for all relevant and known factors (and, when statistical differences are tiny, they must also take into account possible unknown confounding factors). The current authors have highlighted this fallacy clearly.

This detailed critique is long overdue, and is an important contribution to the ongoing debate on the well-recognized benefits of hormone replacement therapy contrasted with a small number of uncertain disadvantages. The debate raised by the Million Women study merely frightened women without giving them a clear view of the potentially valuable benefits balanced against a theoretical risk. Women need clear, balanced, accurate and unemotional information about the quality of published scientific recommendations. The Million Women study failed to do this, and the current article goes a long way to remedying this.”

Prof Fraser has limited availability for interviews today

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The following comments were compiled by our colleagues at the UK Science Media Centre

Comments from Valerie Beral, Professor of Epidemiology and Director of the Cancer Epidemiology Unit, University of Oxford, and Richard Peto, Professor of Medical Statistics & Epidemiology University of Oxford:

“HRT is one of the most important causes of breast cancer in the world and women can easily change their risk by stopping.” Professor Valerie Beral and Professor Richard Peto, Oxford

Prof Dame Valerie Beral:

This paper is a re-statement of views held by many consultants to HRT manufacturers (as these authors are) attempting to dispute evidence about the adverse effects of HRT. The issues raised are not new and have been refuted previously.
The authors omit to say that Million Women Study findings, of an increased risk of breast cancer in users of HRT, especially of oestrogen-progestagen combinations, have been replicated in over 20 other studies. The totality of the worldwide evidence is now overwhelming.
In line with the findings from these studies, the recent large decrease in HRT use has been followed in many countries by a nationwide decline in the incidence of breast cancer.

Prof Sir Richard Peto:

A. Changes in hormonal stimulation of invisibly small clumps of hormone-sensitive breast cancer cells can have a BIG effect on cancer rates within just ONE OR TWO years.
Ordinary breast cells can be stimulated to divide by the female hormone, estrogen. Even when one cell from the breast has gone wrong and has turned into the seed of a growing cancer, that cancer can still be dependent on the continued stimulation by the body’s own oestrogen. Hormone-sensitive breast cancers can, however, be shrunk (and sometimes cured completely) by drugs such as tamoxifen, which block the action of oestrogen on the breast cancer cells.
In women who have had a hormone-sensitive breast cancer apparently completely removed from their breast, invisibly small deposits of cancer cells may remain either nearby or in distant parts of the body that, without drug treatment, would cause breast cancer recurrence and eventually death.
Our review of the randomized trials of daily tamoxifen vs no tamoxifen (Lancet 2011, 378: 771-84) showed that daily tamoxifen halves breast cancer recurrence rate during the first year or two, and that these rapid gains persist. These trials also showed that tamoxifen prevents one-third of the deaths from breast cancer.
A few breast cancers are not hormone sensitive, and tamoxifen does not help patients with this type of cancer.

B. Hormone replacement therapy (HRT) was supposed to replace the body’s own oestrogen after the menopause, and many non-randomized studies have produced strong evidence that it can cause a substantial risk of breast cancer.
The Million Women Study has shown that oestrogen-progestagen HRT, the type most commonly used in the UK, substantially increases the risk of developing a hormone-sensitive breast cancer. As is biologically plausible, in view of the rapidity of the benefit from tamoxifen, the HRT-associated risks fall rapidly after use stops.
In the Million Women Study participants were recruited just before they attended a breast screening clinic, at which some cancers were detected. But, even if attention is restricted to cancers that were detected only later, hormone-sensitive cancers are still three times as common in HRT users as in non-users or ex-users.

Thus, the Million Women Study provides strong, biologically plausible evidence of causality, i.e. of an increased probability of getting breast cancer among otherwise similar women (and a rapid decrease after they stop).

Hazel Nunn, head of health information at Cancer Research UK, said:

“Women shouldn’t be unduly worried by this latest review of HRT and breast cancer risk. HRT can be an effective short-term treatment for menopausal symptoms - women taking it should try and use the lowest dose possible for as short a time as they need it.

“If you are considering starting or stopping HRT, or using it for a long time, you should discuss it with your doctor. The issues are different for every woman and your doctor will be able to help you weigh up the benefits and risks of different types of HRT and make the right choice based on your own circumstances.

“In the UK, HRT use has been falling since the start of the Millennium. Studies suggest that in 2005 there were 1,400 fewer cases of breast cancer in the UK among women aged 50-59 than would have been if there had been no drop in HRT use.”

Comments from the International Menopause Society:

President-Elect of the International Menopause Society, Professor Rod Baber (Sydney) said:

“This review of The Million Women Study (MWS) highlights the problems associated with any observational study regardless of size. Potential biases inherent in any observational study make it difficult for such studies to accurately comment on relative risks of less than 2 and this paper identifies them in a clear concise manner. In the MWS identified biases including time order, information and detection bias, confounding, internal and external consistency may all have contributed to the excess risk of breast cancer with HRT use found in this study. HRT may contribute to increased breast cancer risk but the evidence from this study is flawed and does not assist in the decision making process.
“Every woman has individual risk factors for breast cancer, a number of which are modifiable and she should discuss these with her physician when considering whether or not to use hormone replacement therapy so that an accurate assessment of risks and benefits may be made”

International Menopause Society Board member, Professor Anne Gompel (Paris) said:

“This paper is a meaningful analysis of the MWS by an expert in Epidemiology, and puts forward the fact that the numbers of patients included in a study does not guarantee the accuracy of results. I would advise everyone to read this paper closely, since it highlights some of the important requirements of a good quality epidemiological study. For example, Professor Shapiro shows that the real relative risk is actually difficult to evaluate when it is under 2.
“There are other studies which do show risks and benefits for HRT, so I believe that the take home message is that, for a given woman, the important evaluation is her own risk. Recent papers on breast density, alcohol, obesity and exercise suggest that taking all these factors into account should help to identify which patients are at risk. HRT does not carry the same risk and benefit for each woman; some women will have increased risks, some will have only benefits, and this also applies to breast cancer.”

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* Does hormone replacement therapy cause breast cancer? An application of causal principles to three studies Part 4. The Million Women Study, Shapiro et al., Journal of Family Planning and Reproductive Health Care, doi: 1136/jfprhc-2011-100229