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Ageing brain, Fish Oils, Adaptive Trials, Yoga

Deciding between healthy ageing and early dementia, fish oils, and evidence for the health benefits of yoga. Plus what does being in an adaptive trial mean for patients?

Deciding between healthy ageing and early dementia; how useful are modern imaging techniques in deciphering this difficult question that many families are grappling with. Margaret McCartney tries to make sense of conflicting research on the impact of fish oils on children's reading ability and memory - how can the same research group, in the same university run two trials and get completely opposite results? And recently Baroness Tessa Jowell called for more access to adaptive trials but what does this type of research actually mean for patients taking part? Plus the evidence for the health benefits of yoga.

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28 minutes

Programme Transcript - Inside Health

Downloaded from www.bbc.co.uk/radio4

 

THE ATTACHED TRANSCRIPT WAS TYPED FROM A RECORDING AND NOT COPIED FROM AN ORIGINAL SCRIPT.  BECAUSE OF THE RISK OF MISHEARING AND THE DIFFICULTY IN SOME CASES OF IDENTIFYING INDIVIDUAL SPEAKERS, THE BBC CANNOT VOUCH FOR ITS COMPLETE ACCURACY.

 

 

INSIDE HEALTH – Programme 10.

 

TX:  20.03.18  2100–2130

 

PRESENTER:  MARK PORTER

 

PRODUCER:  ERIKA WRIGHT

 

 

Porter

Coming up over the next half hour:

 

Supplements for schools – Margaret McCartney tries to make sense of conflicting research on the impact of fish oils on children’s reading ability and memory.

 

Adaptive trials – heralded by some, including Labour peer Tessa Jowell, as a more flexible, faster way of developing new treatments for cancer.  But what does being in an adaptive trial actually mean for patients?

 

And the health benefits of yoga – not the sort of thing we normally cover on Inside Health, but when the evidence-based Cochrane library set out to assess whether yoga helps people with conditions like back pain and heart disease, we couldn’t resist asking what the researchers discovered.

 

But first, a question from a listener that I suspect will rings bells with most of you, for one reason or another.

 

Clip

I’m 84-years-old, I’m physically very fit and walk and swim and recently I’ve been under quite a lot of stress and I’ve been finding that I’m losing my memory, short-term memory, forgetting things and I obviously saw my doctor who arranged for me to have a scan.  So, what I’d like to know is, is it possible to differentiate from a scan what is signs of early dementia or the ageing process of a healthy 84-year-old brain?

 

Porter

It’s an issue that affects most families.  If you are not worried yourself, then you may well have a parent or grandparent grappling with this question.  Scans are just part of the diagnostic process but how effective are they at deciding what’s normal and what’s not when it comes to the ageing brain?  I know just the man to ask.

 

Nick Fox is Professor of Neurology and Director of the Dementia Research Centre at University College London and he has a special interest in the early detection and progression of dementia.

 

Fox

The brain, which is this amazing convoluted shape, packed into this tiny box we call the skull, is losing volume year by year throughout our 20s, 30s, 40s and 50s.  How much?  Much less than 1% during that time, .2%, but that gradually increases, so that in our 70s we’re losing about a half a percent per year.  And that’s an average of everybody.

 

Porter

How do we know that?

 

Fox

We know that historically from post-mortem.  Large samples going back hundreds of years actually, there were records kept – autopsies, post-mortem examinations were done.  Some actually from the former Soviet Union where brainwaves were carefully catalogued and people looked at what was the average brain weight of a 40-year-old or a 45-year-old or a 50-year-old.  But it’s only recently that we’ve had good imaging data that has been able to say not how on average what the brain looks like after death but how it changes in life.  And so, there are good longitudinal studies now of this brain imaging and interestingly they are actually fitting with those cross-sectional studies.  So, we do lose a small amount of brain volume and mass through our 20s, 30s and 40s and then as we go into our 60s, 70s and 80s that accelerates.

 

Porter

How do we know what’s normal though?  So, if our brains are shrinking and becoming less powerful as we get older, when does that become a clinical problem?

 

Fox

It’s often difficult. What we use historically is normative data and by that I mean a large number of people who are normal or healthy for that age.  But of course, like anything your brain is hugely variable between people.  So, imagine your hand size, just because your hand is smaller than somebody else’s doesn’t mean that it’s lost volume.  If you glance across at my hand it’s ridiculous to start worrying that there’s something wrong with your hand or my hand because one is bigger or smaller.  What really matters is the change that’s happened to you or to me.

 

Porter

But herein lies something that puzzles me and that’s when we’re looking at the brain now using modern imaging, so a CT or a MRI scan, how do you know, if you’re taking a picture of my brain, I’m 55, take a picture of my brain now, it’s a snapshot of what’s happening to my brain, how do you know if it’s a. normal and b. whether it’s shrinking more rapidly or less rapidly than somebody else’s – you don’t?

 

Fox

We’re very good at picking up an abnormality, something that shouldn’t be there we’re very good – a brain tumour – we know that shouldn’t be there.  You’re absolutely right, it’s much harder to know whether the brain is shrinking more than it should be and how we do that is we look at the brain and we see how much space there is around it but there’s wide variability, so you have to be – have gone a long way from normal before a radiologist or a neurologist will look at a scan and say – that’s really not right.  So, we have – this looks very normal, we’re okay with that – this looks really very abnormal and might suggest a particular disease, such as Alzheimer’s disease.  And then there’s a big grey area between where we think possibly, probably normal for age.  And that possible, probably is all down to that wide variability between what you were born with and that wide variability of what the slings and arrows of age have dealt you.

 

Porter

But at Inside Health that’s the bit that we’re interested in, is this grey area, because it’s an area that puzzles clinicians, it’s an area that puzzles our patients.  So, how big is that grey area?  I mean if you were to take a scan of a group of people in their 60s or 70s what proportion might fall in that area where there’s a bit of a thing going on there, we don’t know if it’s suspicious or not?

 

Fox

If you take a snapshot of a lot of people and they were all healthy, by definition, some people will seem at one edge of the distribution because of course they must be.  If we say that something’s abnormal at, let’s say, the bottom 5% or 10%, we take enough people, there’ll be some people in that bottom 5 or 10%.  The key thing is not whether they’re at the edge of that distribution but how predictive that is of a disease process.  I think as a clinician I’m much less interested in whether or not your brain or your hand size is small compared to the rest of the population but whether it’s abnormal to the extent that I can predict that you’re at higher risk.  So, this grey area for a disease like Alzheimer’s disease, where the question is, is this normal ageing or is this early Alzheimer’s disease, is probably, on a cross-sectional scan, two or three years of change.

 

Porter

So, that’s not a big difference.

 

Fox

So, what we think is that the disease process has got to be present for quite some time before it becomes obvious.  So, that two or three years is not two or three years of normal ageing, it’s two or three years of the beginnings of Alzheimer’s.  So, by the time somebody has had the disease for two or three, four years scans look very different from normal.  If you’re in the earlier stages of a disease, like Alzheimer’s disease, where you lose volume, it can be very hard to tell.  And that often is very frustrating for people, clinicians and patients, when they’re told that the scan looks probably normal for age. 

 

Porter

This is the great conundrum, isn’t it, people come and see you because they’re concerned about symptoms, maybe memory loss, maybe confusion, whatever, you do a scan and they’re at the beginning of this process and you can’t tell by looking at the scan whether that’s normal ageing, is what you’re saying, for sure or whether they’re at the start of a more rapid decline?

 

Fox

For volume loss you’re absolutely right.

 

Porter

Is there anything else you look for on the scan besides volume loss that’ll give you a clue?

 

Fox

We look at certain regions more than others – the hippocampus to do with memory.  But we also look at whether or not there’s evidence of vascular damage, because that’s the other process.  If you like, the most common pathologies we’re worrying about in this setting and where the grey areas of what’s normal and what’s abnormal ageing, really come into play, are two processes – neurodegeneration, diseases like Alzheimer’s disease and vascular, mini strokes, tiny vascular damage that build up and in time would lead to vascular dementia.  And those are the two big disease processes which border on normal ageing.  What radiologists, when they look at scans and just do a visual assessment, they have that database in their head, having seen lots and lots of people’s scans and it is a remarkable skill that they kind of hold what I think is normal for a 55-year-old…

 

Porter

In the same way that if I met someone in the street and they said they were 55 I’d have an idea whether they look normal or not?

 

Fox

Exactly and you probably have the same sort of uncertainty that we have in judging a scan.  So, you see somebody and you might say – gosh they look pretty well preserved, I was really surprised that they were actually 65, they could have passed for 55 – the same is probably true for scans.

 

Porter

But I am meeting all sorts of people from all sorts of walks of life, a radiologist is only looking at scans that have been ordered by another doctor that’s worried about a patient.  Which suggests that that population might be skewed in some way – at 55 they might look more poorly for instance.

 

Fox

Ah but there’s lots of normal scans I’m afraid that come through.  There are people who are scanned because they have their headache or they have their dizziness, where we’re not looking for neurodegeneration.  And so, that is the sort of thing that actually leads to their head database of the radiologist.

 

Porter

So, just to be clear, I’m imagining the radiologist sitting in their room looking through piles of these scans, I mean they are simply looking, they’re not taking detailed measurements necessarily, they’ve just got a pattern that they’re looking for and they can spot when things are awry?

 

Fox

In most clinical situations that’s absolutely right…

 

Porter

They’re not comparing to some database.

 

Fox

No, it’s a visual assessment.  The database is in their head, that’s their clinical experience.

 

Porter

How useful is doing a scan?

 

Fox

I find they’re really helpful.  So, what I’m looking for is the pattern of change and I would be looking for – if I’m worried that you might have Alzheimer’s disease, you’re complaining about memory and I don’t know whether that memory complaint is because you’re a bit anxious, you’re sleeping badly, whatever or it’s really the early stages of Alzheimer’s disease.  I will look specifically at memory areas and say does that look a bit smaller than the rest of the brain in terms of it is disproportionately being affected.  And it’s picking up those patterns.  What we have had as guidance, which I think has been sensible guidance, from NICE is that people should have a scan unless there’s some reason not to, it’s obvious that they don’t need one.  And that seems to me sensible.  Now there are, out for consultation at the moment, draft guidance and that includes a slight change, which is that one should consider imaging.  That may sound like it’s exactly the same thing, doesn’t it, but actually the danger would be that in certain settings people are off the hook.

 

Porter

So, scanners are busy, hospitals are short of cash, scans are expensive.

 

Fox

There is always the risk that someone’s short of money, that they might say well we don’t really need those scans.

 

Porter

And why might that bother me as a patient going to such a clinic where they’re doing fewer scans?

 

Fox

If you use the me or my test, that’s the what I would like for me or my family, I would want somebody to have had a scan.

 

Porter

Professor Nick Fox talking to me at the Dementia Research Centre at UCL.

 

Continuing with brains – albeit at the other end of the age spectrum – fish oils and school children.  New research published earlier this month concluded that fish oil supplements don’t boost reading ability or memory in children who are struggling academically.  Yet, six years ago the same group from the University of Birmingham gained widespread coverage for finding the exact opposite – that fish oil supplements did boost performance at school, prompting many a parent to give them to their children.  Confused?  So were we.

 

Margaret McCartney has been looking at the conflicting evidence and is in our Glasgow studio.  Margaret, two trials, two very different results.

 

McCartney

This time round we have a paper saying that fish oils don’t make a difference but how much media coverage did it get?  Practically none.  Rewind to 2012, when this group’s first paper came out and it was absolutely everywhere – we had parents in the newspapers saying that their children were for the first time interested in classical music, they were asking questions about everything – mechanics – and they wanted to know about engineering, they wanted to know about physics and science and wasn’t it astonishing.  So, when we’ve got, what looks like, positive results we have very positive media coverage, effusive, with great stories but when we have a trial that shows that something doesn’t work it’s a bit quiet.

 

Porter

Publication bias.

 

McCartney

This is fascinating because if we just get our information from newspapers and the television…

 

Porter

As most people do.

 

McCartney

… we could be profoundly misled.  And I don’t know if you remember back to 2006 there were a lot of trials being done in England, not very good quality in many cases, many without a placebo and many without a control group, which made it look as though fish oils were quite good.  What we didn’t have was really high-quality studies.  And this group have come up with two really good studies, placebo controlled randomised control trials, the best sort of stuff you can get, following children up very carefully over 16 weeks for each one.  The first time they found small improvements in some areas.  Now the additional problem is that at that time there was no staggering improvement in these children, there were some small differences that were noted, but the newspapers went to town on this, you would have thought a miracle had been discovered.  In fact, the NHS website behind the headlines debunked a lot of them at the time and illustrated what the authors themselves had said which was we need to repeat this study because we’re not completely sure the results we’ve found are true, we need to do this again, we need to try and repeat it and make sure that the result holds.  And they have repeated it – the result does not hold.

 

Porter

So, what they’re saying now is that their initial findings were doubtful and that the second study’s the correct finding.  Because I mean you could look at it from the other way – if I play devil’s advocate – I mean which study should we believe here?

 

McCartney

Well what you really want to do is look at all the studies and then what you want to do is exclude the ones that are really poor quality, that we can’t rely on at all.  And actually, if you go and look in the literature there’s actually been quite a few studies now and the higher quality of the study the less effect there is on reading and behaviour for fish oils in children.

 

Porter

Margaret, looking at the two trials that this group from the University of Birmingham did, I mean they were both similar sized, so why did they get a different result, what did they do differently second time round that perhaps made this result more accurate in your eyes?

 

McCartney

Well, I’m not sure whether they did things necessarily differently, certainly they tried to improve the way they’d done things to get a better-quality result.  But I think what this illustrates is the wider issue in medicine and psychology, in particular, sometimes called the reproducibility crisis, which means that quite often we have set our store very high on research that was done previously but we’re not able to do it again, we’re not able to reproduce it.  And why might that be?  Probably lots of different reasons.  What you don’t want to have is a treatment or an intervention that only worked in one group of people in one place at one particular time.  You want to be confident that you can keep doing that in different populations at different times, and so that’s why it’s really important to ensure that you’re building on solid foundations, that you’re not just taking bits of a study that are actually not particularly reliable and trusting them more than you should.

 

Porter

Margaret, talking about the importance of quality research I wanted to ask you about adaptive trials, following Baroness Tessa Jowell’s call earlier this year for more of this type of research to be done in the field of cancer.  The Labour peer has a brain tumour and believes adaptive trials would allow volunteers to take part in a faster more flexible type of research that might allow them to switch to more promising treatments sooner.  This is what she told Nick Robinson on Today.

 

Clip – Today – Tessa Jowell

Well the important fact about an adaptive trial means that it can start, not achieve what you want and then move on to the next version.

 

Robinson

You don’t simply have to wait for a set number of weeks or months…

 

Jowell

No, exactly, exactly.

 

Robinson

And that allows you to try more than one thing.

 

Jowell

Exactly.

 

Porter

Margaret, we’ll go into the characteristics of what makes a trial adaptive in a moment but first of all, do you think they’re good for patients?

 

McCartney

Well they might be and they also might not be quite as good as the standard trials we’ve got already.  What I think these trials are trying to achieve is something that everyone wants, which is getting a clear answer sooner rather than later because obviously patients in this position do not always have time on their side and they want to get to know what the effective treatment is for them as quickly as they can.  So, I can understand that.  But there’s lots of issues with adaptive trials, particularly because the people are moving treatment arms during the trial, you have to be absolutely sure that you’re going to know at the end of the day whether that treatment has helped or hindered that patient.  I think it may help some people with some conditions but adaptive trials have many uncertainties about them.  I’m not sure that it’s quite so simple at all, to be honest.

 

Ashby

My name is Deborah Ashby and I am Head of the School of Public Health at Imperial College and I’ve been working in clinical trials for more years than I care to remember.

 

The reason we do clinical trials is to learn.  But sometimes it’s frustrating that we don’t learn fast enough.  So, what an adaptive trial does is try to learn faster.  Everybody wants to the answer, if you’re a patient who needs something, you already need the results of the trial to inform your treatment.

 

Porter

Well Tessa Jowell and cancer being a good example – they don’t want to wait a decade for an answer, they want an answer much quicker.

 

Ashby

They want an answer now.  Now some trials are intrinsically – you’ve got to wait a long time, if you want to know the effect of a treatment on 10-year survival there’s not much option but waiting 10 years.  But there’s some other things where the reason for slowness is actually that perhaps there’s a small number of patients or there’s a lot of treatments coming through and we don’t really know which ones to test out first.  Do we do them sequentially, how do we do them?  And so, sometimes by clever use of trial design you can learn the answers a bit faster especially to these early stage questions.

 

Heneghan

In a conventional trial we have a protocol that we set out at the beginning of the trial and we stick to it, there are no modifications whatsoever.  Unless we find something seriously harmful going on.

 

Porter

Carl Heneghan is Professor of Evidence Based Medicine at the University of Oxford.

 

Heneghan

In an adaptive trial you are allowed to modify some key components of the trial as you go along.  But you have to set out them adaptations before you start.  And what it allows you to do is adapt certain things, like one of the things is the sample size.  So often you might – I might do a trial and I’ll say we’re going to recruit 400 people but as I come towards the end of that and analyse that sample size I realise I’ve got it wrong and there may be too few people to determine if a treatment’s effective.  So, an adaptive design might allow me to recruit more than the 400 people.

 

Porter

And that differs from a conventional trial in that really in most conventional trials it has to run its course.

 

Heneghan

Correct, and you can’t deviate.  I’ve been involved in trials where we’ve come to the end and we’ve gone – we seem to have an effect here but it’s not statistically significant because we didn’t recruit sufficient people.  And that’s really disappointing.  And that’s at the end of a three-year trial.

 

Porter

And the only way you can then do that is to do another big trial with more people.  But if you’d been doing an adaptive trial you might have been able to have tweaked it halfway through is what you’re saying.

 

Heneghan

Yeah, because often when you’re making up the sample size calculation you’re not quite sure how much benefit you’re going to get, so there is a general bit of guess work to try and say this size of effect will correspond to 400 people in this trial.  And if you get that wrong you’ve blown three years of research.

 

Porter

But it must be quite a challenge as an organiser of a trial like this to try and work out all the what ifs at every junction going forwards because they’ve got to be laid down in black and white from the start.

 

Heneghan

And that’s one of the issues is you have to run simulations to try and work out what might and might not happen.  And some people are saying well actually the amount of work you have to do to get that right, you’re better off just starting the trial and cracking on.  And the issue right now is – cancer’s a very important area, sheer number of treatments and molecules coming to the market, if you’d have gone back 25 years ago there were probably three or four agents, now there are different receptors, different resistant mechanisms, different pathways which mean that at any one time there are 10s if not 20s of drugs just for one cancer in development.  So, what we’re saying is some of these processes, right at the outset, you can adapt, so it’s not you make it up as you go along, before you start the trial you can adapt the methods you use.  So, one example would be you might start out with different doses.

 

Ashby

So, a conventional trial, if we have five doses to test, would take five groups of people, randomised between them and follow them up.  Now it might be that the lower dose is pretty useless and so actually we’ve, if you like, wasted the time of those patients who are on the lower dose, whereas if we learn maybe we could randomise more patients the higher dose and learn more about the high dose.  So, the design adapts as we go along.

 

Porter

The only concern that I have with this idea of adaptive trials is who’s making the decision to adapt the trial?  Is that being done because they want to get a better result, so you might say ooh this drug doesn’t seem to be working, perhaps we’ll try and give it a little bit more, give it a little bit longer or…

 

Ashby

That’s why it has to be done in a very planned way.

 

Porter

Because the term adaptive may make some participants think that it’s flexible.

 

Ashby

Patients enter the trial consented and of course they can withdraw at any stage.  But having accepted that it’s not then their choice what treatments they follow.  In many cases some of these will be placebo-controlled trials, so they might be what we call blind to the patient, they may not even know what treatment they’re on.  But certainly, they will be following a sort of pre-specified plan that if certain things happen, if they respond in certain ways, then something else might happen to them or the next patient might get a different dose.  It’s not under their control in the way that you might like.

 

Porter

They’re not masters of their own destiny in terms of saying oh actually I’d quite like to try that arm instead?

 

Ashby

No, they don’t get to pick and choose what treatments under these trial designs.

 

Porter

Do you think we use adaptive design enough, could we be using it more?

 

Ashby

I think there’s certainly a role for them to be used more. 

 

Heneghan

Regulators are keen on it, manufacturers are keen on it and now what you’re seeing is the public’s really keen on it, so it’s going to happen.  And thinking cancer, it has huge potential if – if these trials are done robustly and second is, we understand clearly the adaptation to have had to be decided before the trial, not after the trial because if you’re doing it after the trial’s started that’s called making it up and we see that quite a lot in terms of switching outcomes, protocol violations and that shouldn’t happen.

 

Porter

Professors Carl Heneghan and Deborah Ashby.  And there is more information on adaptive trials on the Inside Health page of the Radio 4 website, where you can also subscribe to our weekly podcast service so, no matter how busy you are, you need never miss another episode again.

 

Yoga actuality

Now the shoulders to soften…

 

Porter

The putative health benefits of yoga…

 

Yoga actuality

Legs are either bent or straight…

 

Porter

Not normal fare for us here at Inside Health, but when the renowned Cochrane Library decided they warranted further investigation we invited the lead researcher to come and tell us what the evidence revealed. 

 

Susan Wieland is Assistant Professor of Family and Community Medicine at the University of Maryland, and Coordinator of Cochrane Complementary Medicine.

 

Yoga actuality

...exhale, naturally softening down.

 

Wieland

There was a review of yoga for low back pain and we actually found that when it’s compared to doing nothing it’s better in terms of improved back related function and pain.  Although the amount of change in pain was pretty small.

 

Porter

Any harms evident?

 

Wieland

Yes, there were minor adverse events but there was nothing that was serious.  Unless you do something kind of wild and crazy like put your leg behind your head when you have back pain.

 

Porter

Not that I could get my leg behind my head anyway.

 

Wieland

With or without back pain, same.

 

Porter

What else was positive?

 

Wieland

There was also a review published a couple of years ago on yoga for asthma and there, there were improvements in health-related quality of life and also in asthma symptoms.  Just as in the yoga for low back pain the outcomes were only followed up to about six months.

 

Yoga actuality

… one side or rock backwards and forwards and coming to sitting.

 

Porter

One of the areas you looked at was cardiovascular disease, prevention both primary, so that’s healthy people who’ve never had a heart attack or stroke and people who’d had a heart attack and stroke.  Did you find any impact there?

 

Wieland

So, that was a really great example of where there’s just not enough evidence.  So, there’s some short-term evidence for favourable effects on diastolic blood pressure, HDL cholesterol and triglycerides.

 

Porter

All of which are markers possibly for a stroke or heart attack.

 

Wieland

Exactly – markers of risk of heart attacks.  But they didn’t have studies that were long enough, that followed people to see whether or not they actually had a heart attack or died or anything like that.  And then they also went and looked at secondary prevention, so in somebody who’s already got coronary heart disease can yoga help prevent a new episode or can it improve quality of life.  And they said we’re only interested in looking for trials that are six months or longer and they found none.

 

Porter

So that’s the problem, so when you turn around and say there’s no evidence that yoga helps ward off a second heart attack or stroke it’s because the research hasn’t been done, it’s not that there might not be an effect?

 

Wieland

Yes, it doesn’t mean that we’ve proven yoga doesn’t help.  But a lot of times it’s quality of life, where we expect to see yoga have an effect.  People with breast cancer can benefit, where it was things like fatigue, trouble sleeping, depression, anxiety.

 

Porter

It’s multifaceted isn’t it, there’s much more of a mental and emotional side to it.

 

Wieland

Yes, it’s often called a complex intervention because it has multiple components.  And those components may interact.  So, they may not act in isolation.  It’s very variable in how it’s implemented, so that’s also very complex.  So, it is tricky.

 

Yoga actuality

…up to the ceiling…

 

Porter

The other issue with these sorts of interventions is that they often polarise opinion.  I mean if you were into yoga you really are in to it and if you’re not you’re probably not.

 

Wieland

Part of the lack of yoga research is because nobody has a big financial interest in the outcomes of yoga.  But there are a lot of people who are really passionate about yoga and believe it can help and want to find that evidence.  So, this can lead to the same sorts of bias you see stemming from financial interests, so, holding back negative publications, fishing for outcomes that are positive.

 

Porter

And then there’s the publication bias.  I mean your study of the back pain got quite a lot of coverage here in the UK, I don’t know if you saw that and I can just see that – our papers would lap up the combination of back pain and yoga.

 

Wieland

Yeah, it’s definitely true that there is a possibility of bias.  And even the systematic reviewers, that’s why Cochrane has teams of systematic reviewers, where I’m not a yoga expert but we did have a yoga expert on the team, as well as some medical experts.  So, it’s something you always have to be conscious of when you’re looking at the evidence.

 

Yoga actuality

Namaste.

 

Porter

Namaste.  And there’s a link to that Cochrane review and Susan Wieland on our website.

 

Just time to tell you about next week’s programme, the last in the current series, when I visit a pioneering eye bank tackling a shortage of donor eyes for sight-saving surgery.

 

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