Joining Forces to Tackle Obesity, 21-22 January 2002
Transcript : Prevention and Management: The Evidence Base
Speaker
Mike Kelly
Director of Research and Information
Dr Caroline Mulvihill
Research Specialist in the Health Development Agency
DR WILLIAM DIETZ: The title of the next section
is "Prevention and Management. The Evidence Base. Findings from the
Health Development Agency Systematic Review of Interventions to
Prevent and Manage Obesity". This will be introduced by Mike Kelly,
Director of Research and Information, followed by Dr Caroline
Mulvihill, the Research Specialist in the Health Development
Agency. Mike?
MIKE KELLY: Can I have the first slide up
please? Can someone from the technical side just give me a clue as
to how you move these slides on?
Okay, well good morning everyone. My name is Mike Kelly and I’m
the Director of Research and Information at the Health Development
Agency. You already heard a little about that from Imogen, my
colleague at the Department of Health, and I’m going to begin by
saying just a few things about what we’re doing with respect to
evidence generally, and then we’ll go on to talk about evidence
specifically, as it relates to obesity.
The Health Development Agency was actually set up to have
English only jurisdiction by statutory instrument following
publication of the Our Healthier Nation white paper. We’re a
successive body to the old Health Education Authority but, unlike
that body, we have no responsibility for running campaigns, for
doing that sort of thing. In particular, we’ve got a role with
respect to the development of the evidence base to tackle health
inequalities in England. And, in particular, to reduce health
inequalities across the broad sweep of public health, including
obesity, but also with reference to cancer, coronary heart disease,
accident prevention and a whole range of other topics.
We’re driven, to some extent, by the research and development
strategy of the Department of Health and the overall project in
which we’re involved has a number of different elements to it. But
what we’re trying to do, is to provide a systematic basis for using
scientific evidence in public health. Now, of course, there’s been
evidence around in public health for years and years and years.
But, the fact is, until relatively recently, there wasn’t a
systematic approach, either to pulling it together, to synthesising
it or applying it to policy. So our task is to do that.
Secondly, to provide high quality evidence about reductions in
inequalities and how they might be tackled. I should say that
that’s actually a rather tricky problem because if you look at the
evidence base in public health in the United Kingdom as a whole,
and ask the question, how much of that evidence collected by
Universities, funded by the Medical Research Council and others,
how much of it actually relates to reducing inequalities and how
much is about describing inequalities? Around about 96% of it is
about describing the problem and a mere 4% is about solving the
problem. So we’ve got to increase that evidence base in that
sense.
Our task is also to bring the knowledge base together,
importantly to identify the gaps - what we don’t know. We had an
interesting presentation this morning on one of the sort of real
problems we have, is that there are huge sways of material about
which we know relatively little and, of course, our task is to
underpin the Our Healthier Nation strategy and the NHS plan.
We want to move towards evidence informed interventions and
improvements in obesity and other fields. We are interested in
trying to improve health status, however you manage that, however
you measure that. Whether by life expectancy, disability adjusted
life years, quality of life, or whatever. We’re interested in
improving the health status of the whole population, but we’re also
interested in improving the health status for the most
disadvantaged. And very importantly, a real trick or a real problem
and the trick you’ve got to do to solve it, is that improving the
health status of the whole population doesn’t mean that you improve
the health status of the most disadvantaged. In fact, over the last
40 or 50 years, we have improved the health status of the
population of the whole of this country but at the same time the
inequalities gradient has got steeper. In other words, many of the
interventions that we have up our sleeve, the things that we can
do, improve the health status of part of the population but not the
whole of the population. And what we have to do is to be able to
break that apart and understand the kind of interventions, which
work in different sectors of the population.
The materials you’ll find on our website dealing with a range of
different topics can be, broadly speaking, characterised as
follows. You will find systematic reviews of other research, you’ll
find synthesis of research based materials - and I’ll talk a little
bit about the synthesis in a second or two - gateways to other
evidence based sites, bibliographical information, routine data
about the topic in question, links to the public health
observatories across the country, sections on what policies are
going into practice at the moment and links to other HDA websites
as well as a pot-pourri of other relevant material.
So, if you come on to the HDA evidence base website, you log on
to obesity and nutrition by the end of this financial year - a
month or so time - this is the kind of thing that you’ll find.
Our synthesis documents - and in a moment or two my colleague,
Caroline, will be talking about one of these relating to obesity -
follows the following format. We provide an executive summary on
each topic. This is an example drawn from the first one to be
published in a week or so time on the prevention of accidental
injury. The main document following that executive summary has a
protocol, an audit trail, about how we did what we did, how we
gathered the evidence together. You’ll find examples of evidence
that we know about what works, what’s effective - a series of
recommendations relating to research and relating to policy. The
headline statements in the content will identify where we know
evidence to be strong, how weak it might be, if it’s inconsistent -
and a lot of evidence is inconsistent - and how current it is. And
that’s not just how up to date with the kind of cultural changes
that Will Hutton was talking about in the first section. To what
extent, did what we know 10 years ago might it still be applied
now, where other changes have occurred?
Where are the gaps? What we don’t know - very, very important.
What are the implications for inequalities? Very, very important as
far as we’re concerned - as far as the ministerial team are
concerned, too. What do we know about cost effectiveness, if
anything? There are large areas in public health where we’ve got
good cost effectiveness data. There are others where we know almost
nothing.
Recommendations for future work and recommendations for policy.
This is the framework of our synthesis documents and by the end of
this financial year - in about 6 to 12 weeks time - we’ll have
about 10 of these on stock and on our evidence based website for
you to look at.
Now, we’re going to focus for the rest of the session on the
content on this evidence based approach as it applies to nutrition
and obesity and the leader of the team at the HDA on nutrition and
obesity is Caroline Mulvihill, who is going to come up now and talk
you through the headline findings about what we know to be
effective with respect to these issues of obesity and nutrition.
Caroline?
DR CAROLINE MULVIHILL: Good morning everyone.
First of all, I’d like to thank the National Audit Office for
inviting us to present today. As Mike has introduced our talk, my
colleague and I, Rob, who’s sitting over there, have been working
on a synthesis of what works to prevent and manage obesity. Now
this will be available by the end of March 2002 on our evidence
base website. This work will be continuously updated. This is a
moving feat because we are conscious that new evidence is coming
out all the time. There’s going to be two new Cochran views coming
out shortly plus the Centre of Views and Determination review on
obesity is currently being updated. When that is available we will
put this on our evidence base as well.
And as you can see, here’s an example of our evidence base
website and if you look at the bottom you can actually search by
topic, population, setting and by types of evidence.
Now the vignette of our work is mainly on lifestyle
interventions, so its diet, physical activity, behavioural therapy,
that kind of thing. Our synthesis will not be covering the surgical
or pharmacological treatment of obesity as this work is currently
being undertaken by Nice, so it seems pointless to duplicate the
work, but we have established links with Nice and at some point
we’ll be sharing our learning.
The methodology now for developing our synthesis: We did an
extensive search of the published literature dating back from 1996
through to December 2001. We followed up any queries with the
literature with authors, we checked the reference lists of all the
papers that we had coming in and we also consulted outside experts
and, at this point, I’d like to acknowledge the help of Doctors’
Caroline Summerbell, who’s been acting as an external adviser to
this work, and also to Dr Alison Abinall from the University of
Aberdeen who helped us with research. She is currently doing the
update of the CRD review of obesity.
The literature was collated and the quality was assessed in
terms of transparency, for simplicity and relevance, and in total,
nearly 140 review papers have been collated at this stage and Rob
and I have read all these papers, filled in critical appraisal
sheets and we have agreed which ones have gone on to the evidence
base.
At this point I’d just like to highlight something about the
papers that we have been gathering. We have been looking at reviews
of studies where weight loss has been one of the aims of the
studies. So where there’s been change in BMI, change in weight,
change in percentage overweight, we have included those studies
under our evidence base. So there are some interventions, say like
healthy eating interventions or physical activity interventions
where, although, as a by-product of intervention you would expect
some weight loss. If it’s not specifically in the aim of the
project we have not included this onto this current piece of work
and we decided this at the end stages just to make the work a bit
more manageable because, as you appreciate, this work can just grow
and grow and grow.
As I said, this is very much a review of reviews and not a
systematic review of individual trials. There are many centres
across the country who are doing systematic reviews and we decided
we would just do the review of reviews. Therefore, the work is
based on systematic reviews, analysis and synthesis. And where
there were no systematic reviews in a particular area we have
decided to go down a level of evidence to high quality literature
reviews in order to fill that gap.
So, as we are mainly speaking to systematic reviews, our finding
a main base on RCT trials. However, if we have gone down by a layer
of evidence to a high quality literature review these tend to be
based on non-RCT, experimental or observation studies and where we
have used lower levels of evidence in our synthesis, this will be
indicated.
I’d now like to go on to present some of our top line findings
from this work and it will mainly be on prevention, treatment and
maintenance. And, again, I’d like to say this is very much top line
findings and I’ve made the point of not going into too much detail
about intervention. I’ve been very conscious that some of our later
speakers on physical activity and diet are going into this in more
detail.
So, what is the evidence base for the prevention of obesity in
children? As you can see a recent Cochran review has showed there
is limited quality data on the effectiveness of obesity prevention
programmes and, as such, no generalisation or conclusions can be
drawn. And there seems to be a mismatch between the prevalence and
significance of the condition and the knowledge base in which to
inform preventative activity.
Furthermore, another review carried out by Storey on the
prevention of obesity in schools has done only a few primary
prevention research studies, targeted specifically to obesity
prevention, have been carried out and therefore the effectiveness
has not been established. However, there has been some school based
crime prevention programmes that target cardio vascular risk
factors, but these have not proved effective in reducing the
percentage of overweight.
However, there is some promising findings from the evidence,
mainly in relation to sedentary behaviours and there is encouraging
reductions in sedentary behaviours, may be useful. And this is
based on two studies of American schoolchildren and as you can see
the recent Cochran review also reinforces this finding.
Another promising finding, which was found in the, again, the
CRD review was that family therapy sessions have been found to
prevent the progression of severe obesity in children. And this was
based on one study carried out in Sweden.
As you can see, talking now about the prevention of obesity in
adults. There is very limited evidence to date. Only three
community-based studies have been carried out and these have
concluded that community based obesity prevention methods have not
been proven effective. There is insufficient evidence to recommend
in favour for or against community based obesity prevention
programmes. And this has been found by a Canadian review carried
out by Duccates. However, as we have been discussing for the last
two days, many authors consider that with the huge health risks and
the financial costs associated with obesity, priority should be
given to the prevention of obesity over weight loss interventions.
There is, therefore, an urgent need for further research in this
area.
But again, like children, there have been some promising
findings and some community based education programmes linked with
financial incentives may be effective. And this is based on one
theory to be carried out in the States, which is the Panda
prevention study.
Let’s move on to the treatment of obesity in children. There
have been from two good quality trials from the USA to suggest that
intervention is designed to reduce sedentary behaviour are the most
effective, which is very similar to the preventing of obesity
findings. There’s lots of conflicting evidence regarding
effectiveness of treating children and adults together. There’s
been three studies, I think, carried out but they’ve all used small
sample sizes and all conducted by the same North American research
group.
And finally, the benefit of parental involvement may vary
according to the age of the child. And may be a greater value of
those aged five to eight years. Again this is carried out in
studies looking into age groups 5 to 8 years, 8 to 13 years and 12
to 16 years, and the research has found that it was the 5 to 8
years that was most effective. I’m sure anyone out there who are
parents appreciate that as children get older they’re less likely
to comply with their parents’ wishes.
Therefore, there is a lack of high quality research or
systematic reviews regarding the role of physical activity in the
treatment of obesity in children. However, there is going to be a
forthcoming Cochran review on this area, which hopefully should
update some of this evidence.
I’d like to now move on to the treatment of obesity in adults.
I’d just like to cover the main dietary strategies here. The first
one being low calorie diets which is classified as a diet of 1,000
to 1,200 calories per day. This is from the National Institute of
Health report. It’s an American review carried out in1998 and they
found 34 RCT studies - there’s quite a lot of evidence there on the
role of low calorie diets - and they found that regardless of the
length of the intervention, low calorie diets did result in weight
reduction and they can reduce total body weight by an average of
about 8% over 3 to 12 months.
In addition, four studies that included a long-term weight loss
and maintenance intervention lasting 3 to 4½ years reported an
average weight loss of 4% over the long term. These effects can be
long lasting. And finally, four RCTs show consistently the weight
circumference issue, abdominal fat, also decreases with low calorie
diets.
And next I’d like to move on to very low calorie diets, which is
classified as 400 to 500 calories per day. Now, this is basic
common sense but very low calorie diets produce greater initial
weight loss than low calorie diets obviously because they are lower
in calories. However, the long-term effect is no different from low
calorie diets. Very low calorie diets is, when in conjunction with
behavioural therapy, produce a greater weight loss, post
intervention after 6 to 12 months compared to very low calorie
diets or behavioural therapy alone. It seems a combination of the
two works well together. However, weight regain is an issue for all
these treatment options and the effect of providing a maintenance
programme following initial weight loss requires further
research.
I’d like to move onto lower fat diets. This is, again, from the
same American review, which found nine RCTs on effective lower fat
diets. These lower fat diets varied from 20% to 30% energy intake
from fat and total calories in these diets range from 1,200 to
2,300 calories per day. And, as you can see, they found little
evidence to support the use of lower fat diets per se, independent
of calorie reduction. And what the second point is trying to say
is, lower fat diets work because they reduce calorie intake. If you
had a diet which was 2,000 calories but had a low fat diet of say
less than 30% intake from fat you will not lose weight. Lower fat
diets work because they help you reduce your total calorie intake.
Now as you all know, fat is a more energy dense nutrient therefore
if you reduce your fat you will reduce your calorie intake.
Before any diet here, I would also like to point out that there
will be other dietary interventions in our synthesis such as the
role of fibre and the provision of meal plans - we just haven’t got
time to cover it today.
Now, the treatment of obesity to physical activity alone: again,
as the slides show, physical activity can be effective in producing
modest weight loss - two to three kilograms independent of the
effect of calorie reduction through diet. However, if your goal is
to use exercise alone as a strategy for obesity reduction you would
have to do an exercise programme which would prescribe an energy
expenditure of 3,000 to 3,500 calories per week. This has been
taken from a review by Ross Inyanson, which although it’s not a
high quality systematic review, this is a case where we’ve used a
lower level of evidence because he’s found this paper quite
interesting. And in order to expend the 3,000 to 3,500 calories,
you would have to do apparently 45 to 60 minutes of purposeful
walking and it would have to be fairly purposeful for 70% in
maximum heart rate on most days of the week. And that’s a fairly
high-energy expenditure. That’s about two to three times higher
than your average physical activity intervention and, to that, 1 to
1½ days your total energy requirement. So if you wanted to use
physical activity alone as a method of treating obesity you would
have to burn some fairly serious calories in order to achieve
that.
And I’d also like now to talk about the combination of physical
activity and diet in the treatment of obesity. It’s found that the
combination of reduced calorie diet and increased physical activity
produces a greater weight loss than diet and physical activity
alone. Now, the combination of the two, you would need two
kilograms more than diet alone and five kilograms more than
physical activity alone. And again, this is taken from the American
review. So it just goes to show that by decreasing your energy
intake, increasing your energy expenditure, that does produce that
double whammy effect in order to treat obesity and it’s not the
"fad" idea as outlined in this cartoon here.
We’d like to just talk a bit more about the role of diet in the
treatment of obesity. The evidence shows that in order to treat
obesity, diet is the more effective method. However, physical
activity does have an important role in decreasing mortality and
obviously reducing cardio vascular risk factors. Although, obesity
does have its own factors that improve with weight loss independent
of physical activity, therefore we’d just like to emphasise at this
point, that in terms of research and policy there should be greater
emphasis on diet rather than physical activity in weight
management.
I’d just like to talk briefly about the role of behavioural
therapy as well. Now behavioural therapy is the modification of
behaviour patterns, new adaptive learning, problem solving, which
is often used in conjunction with dietary therapy. As you can see
here, the American review found that behavioural therapy used in
combination with other weight loss methods provides additional
benefits in assisting patients to lose weight in the short term,
however, these benefits are not found in the long term. This,
therefore, emphasises the great importance of continuing a
maintenance programme on a long-term basis.
And finally, another quote from this report, they found that no
one behavioural therapy appeared superior to any other, rather
multi-model strategies work best - so a combination of various
methods - appear to work best and those interventions with the
greatest intensity appeared to be associated with the greatest
weight loss. However, there have also been some promising findings
in terms of behavioural therapy, which was found in the CRD review.
One of those being queue avoidance, daily weight charting’s been
found to be effective, behavioural therapy by correspondence - this
is mainly in relation to, like long term outcomes - extending the
length of the intervention period and they also said that these
interventions would be of benefit when used with in conjunction
with other weight loss strategies.
At this point, I’d also like to talk briefly about alternative
therapies. Now the CRD review was carried out in the UK and the
American review did say that they would be looking at alternative
therapies. However, they were unable to find any RCTs that would
meet their inclusion criteria. They would only include trials where
the observation period was over one year so were unable to include
any alternative therapies in their reviews, however, as we are not
in the business of doing systematic reviews and we’re doing reviews
of reviews we have actually found a number of very good systematic
reviews on alternative therapies, which we have actually included
in our work.
The first one being Chitosan. For those of you who are not
familiar with Chitosan, Chitosan is a food supplement and it is
derived from the cuticle of crustaceans. There has been a very good
systematic review on the use of Chitosan and it was found to be
effective in five studies. However, concerns were raised about the
study design and the buyers. These five studies were carried out by
the same research group in Italy and the research was funded by the
supplement manufacturers. Therefore the author here, Ernst and
Pittlar has suggested, "That effectiveness needs to be confirmed by
more rigorous and independent tests".
There has also been a very good review on the use of gua gum.
And this has not found to be effective for reducing body weight.
There is also a number of adverse effects associated with its’ use,
therefore gua gum cannot be recommended. It basically causes some
fairly nasty side effects to the digestive system.
We also found some evidence on the use of acupuncture
acupressure. A systematic review found contradictory results on
effectiveness. Four trials have been carried out - two positive,
two negative - in favour of acupuncture and the most rigorous of
these four trials found no effect on body weight.
And finally, hypnosis. And there has been a whole series of
metro analyses, which have been published on the role of hypnosis.
The first paper was published by Kirsch, who’s listed at the
bottom, and then there was another paper published in response to
that paper by Ellison and then Kirsch responded back so there’s
been a whole series of academic debate, more on method analysis,
methodology, rather than the actual effectiveness itself. But
looking through all these various papers that have been produced,
it’s mainly based on one study that’s been carried out in 1980s,
which did show some very promising findings, which lasted in the
long term. However, there was a problem with drop out rates in the
study. So, therefore, at this point we feel that the evidence
appears promising but needs to have additional and more rigorous
studies carried out to confirm or deny the usefulness of hypnosis,
which is normally carried out in combination with behavioural
therapy. So we haven’t dismissed this method all together because
we think it could have a great potential, but it just needs further
confirmation.
At this point, I’d also like to talk about the maintenance of
weight loss and I’m sure you’re all familiar that it’s generally
accepted that lots of people who lose weight tend to regain it. So
we’d just like to talk about some evidence that we found on
maintenance.
It’s imperative that effective maintenance strategies are built
into any weight loss programme. However, there’s been very limited
evidence to date that we’ve been able to find and most of it’s in
relation to physical activity, therefore we conclude that physical
activity may or may not play a role in long term weight control or
in the maintenance of weight loss. And this finding was from a very
good systematic review carried out by Fockleholm and
Kookanan-Hardular which was just done recently and they found that
high physical activity levels of about 1,500 to 2,000 calories per
week are associated with improved maintenance of body weight and
that the impact of the usual prescribed routines remain very
limited.
There have been some very mixed results from RCTs and
prospective studies on the association between physical activity
and weight change and therefore conclusions cannot be drawn.
And finally, I’d just like to summarise with this table, which
we’ve done sort of, as an overview of the evidence to date
[Reference to visual aid]. As you can see we’ve divided it up into
prevention, treatment and maintenance. And what works, and what is
promising and what is conflicting. And as you can see, under the
treatment in the adult section, that’s where we found the most
evidence and it does go down in order of effectiveness. The most
effective is diet with physical activity plus behavioural therapy.
The next one is diet and physical activity, low calorie diets, very
low calorie diets and, lastly, low fat diets and calorie
restriction. And as you can see there are some empty boxes there.
Now that doesn’t necessarily mean there is a lack of effectiveness,
there is just a lack of evidence, and basically more research is
definitely needed in order to move some of the interventions that’s
in the ‘promising’ ‘conflicting’ boxes over to the ‘what
works’.
And finally, we have also highlighted some gaps in the evidence,
which we’d like to list today. The first one being population
groups. Now as we discussed earlier, low-income groups and minority
ethnic groups are a very much at risk group of obesity. However,
from our research of the literature, there was no mention of these
at all. Some mentioned it in the American literature but we haven’t
tackled this issue at all in the UK.
Also, in terms of research, we feel that a general lack of a
process evaluation of the intervention is being carried out. Many
of them just describe x calorie diet was given to these people and
this amount of exercise, and what we’d like to know is how did they
recruit patients? How did they appear to their diet? Any problems
they encountered, because this kind of information would be very
interesting if we want to do any sort of roll out, at a national
level. Also there’s very much a gap in terms of characteristics of
effective interventions and also a complete lack of evidence on
cost effectiveness and interventions.
And finally also, some gaps that we’d like to have filled in. It
would be quite nice to have some sort of characteristics of those
who have successfully lost weight in the long term. I know that in
the States they have a register of people who have successfully
lost weight and they use that to get the characteristics. Something
like that would be very useful to have in the UK. Also the
effectiveness of commercial weight loss programmes has not been
proven yet and the benefit of targeting specific groups or applying
a blanket approach to obesity to weight management.
And finally, is there a need for environmental population based
interventions?
And that’s the end of my talk. Again, I’d just like to mention
this is very much top line findings and the proper brief will be
available on our evidence base website by the end of March. Thank
you.
DR WILLIAM DIETZ: We have time for a few
questions. Yes, in the back.
QUESTION FROM FLOOR: Thank you. I have a few
concerns about some of the methodology that you have used in
collating this data. And, in particular, I’m a little bit worried
that we’re using different standards of evidence to evaluate
different kinds of trials. So, for example, you’ve concluded that
in relation to prevention, despite the fact that there are huge
community based random out of control trials, which may not be the
best model for assessing prevention programmes, but there’s no
evidence that any of these work or have anything valuable about
them. Yet, with some of the alternative therapies, despite the fact
we’ve got very small scale short term studies in which there have
been serious concerns raised over the methodology, they’re
concluded to be promising. I’m particularly concerned about the
Chitosan one, because Professor Ernst who did the review that you
referred to subsequently did a follow up study himself which was
the most rigorous study of a random out of control trial of
Chitosan and showed quite clearly that there was absolutely no
benefit over and above the dietary advice. And so, I really do
think that if we’re going to take this systematic approach, that it
is important to ensure we’re evaluating all studies against the
same criteria.
ROBERT QUIGLEY: We went into this with a
reasonably open mind about whether or not we look at alternative
therapies and when we first got our hypnosis paper across the table
we thought, "Crank, we’ll throw it out". And then we thought, "Well
actually, why don’t we actually sit down and read it and assess
what the authors have said about the effectiveness of those
processes". For example, the Ernst one that you talk about - the
RCT - he has criticised Chitosan quite strongly, especially those
five papers and he criticised them based on their time period and
the size of their study. The Ernst paper that you talk about had 17
people and went for 28 days so it itself was actually very, very
small and over a very short time period. And, I suppose all we’re
doing is, we’re going in with an open mind and we have got them in
the ‘promising’ / ‘conflicting’ area. We haven’t put the exercise
for the community interventions in the ‘conflicting’, we’ve put
them in the ‘promising’ area, whereas we’ve put the Chitosan and
the hypnosis in the ‘conflicting’ area. It’s just for ease of
presentation that we’ve slipped them into the same category.
DR WILLIAM DIETZ: One more question - way in
the back.
QUESTION FROM FLOOR: Thanks. It’s Ken Fox,
Bristol University. I’m a little concerned that they’re all using
terminology because, one, I don’t want to get into a debate of
whether it’s exercise or diet - I think both are critical. But one
conclusion that you made was that diet is much more efficacious
than physical activity for the treatment of obesity. Surely, you’re
talking about weight loss - short-term weight loss - when you make
that statement. Because many people in this room would say that the
treatment of obesity is about disease management, risk reduction,
long term effects, and so I think that we be careful how we use the
terminology here because that really does send out messages, which
are not really represented in the literature, if you look at
obesity treatment as being a long term management issue.
ROBERT QUIGLEY: I take the point. We did finish
on the final slide saying that the most efficacious treatment is
diet plus physical activity plus cognitive behaviour therapy with a
maintenance programme that goes on long term. But for treatment, we
did break it down by physical activity alone, diet alone and diet
plus physical activity combined. And the point we wanted to make
was that diet alone is far more efficacious than physical activity
alone and that diet plus physical activity is more efficacious than
any of those other two alone. So if you are looking at a group of
interventions that you wanted to run in a country or in a practice
or somewhere, you’d want to look down there and you’d want to make
sure that a large number of them focus on changing people’s diets
and you’d also want, obviously, some that changed physical
activity, but you’d want to make sure that a large number of them
focus on diet.
MIKE KELLY: What I think would help all of
these, in a presentation like this, where we’ve condensed down
evidence which, when this is a printed document, runs to about 80
pages, something like that. You’ll be able to decide, first of all
a transparent account of the different levels in standards that are
being applied which, I think, will answer the first question. We
are not attempting to say, this is all the same thing. We are
saying these are the different kinds of standards or these are the
sorts of criteria with which we’re using and you can judge for
yourself in terms of whether we we’ve kept our own standard and
criteria.
And secondly, trying to weave across a whole range of 140
reviews, and maintain a coherent set of terminology, is simply not
possible because for 140 plus all the primary research has been
done in the first place, uses a variety of terminology and
definitions somewhat differently. We have to, sort of, take a
birds’ eye view on this, but you’ll be able to follow the audit
trail back through to, I think, unravel some of those problems and
difficulties that might emerge from seeing that the headlines of
the statements that are in the presentation this morning.
DR WILLIAM DIETZ: Thank you. In order to keep
the programme on time we’ll take additional questions up here
during the break but let’s take a 15 to 20 minute break.