Examination of Witnesses (Questions 61-79)
PROFESSOR DAME
CAROL BLACK,
DR RICHARD
EDWARDS, DR
ALLAN HACKSHAW
AND DR
RICHARD ASHCROFT
20 OCTOBER 2005
Q61 Chairman: Could I welcome you and
could I ask you, Professor Black, if you and your colleagues could
introduce yourselves to the Committee?
Professor Dame Carol Black: I
am Carol Black. I am President of the Royal College of Physicians.
I have been its president for the last three years and two months
and one day a week I practice as a Professor of Rheumatology at
the Royal Free Hospital. Could I perhaps ask my colleagues to
introduce themselves?
Dr Ashcroft: Good morning. My
name is Richard Ashcroft. I am Reader in Biomedical Ethics at
Imperial College, London, where I work in the Department of Primary
Care and Social Medicine.
Dr Edwards: I am Richard Edwards.
I am a senior lecturer in public health at the University of Manchester.
I originally trained in respiratory medicine, hence my interest
in tobacco, and I am involved in tobacco policy-related research,
particularly around air quality in the hospitality industry.
Dr Hackshaw: My name is Alan Hackshaw,
I am Deputy Director of Cancer Research UK and University College
London Cancer Trial Centre. I have been there for two and a half
years and previously I was a senior lecturer in epidemiology and
medical statistics at Bart's Medical School where I did a significant
amount of work in tobacco and health.
Q62 Chairman: Could I open this session
up and ask you to summarise for us the main health effects of
second-hand smoke and how important they are for individuals and
for public health?
Professor Dame Carol Black: Thank
you very much. The main health effects of smoking would be (1)
lung cancer, (2) heart disease, (3) chronic bronchitis and (4)
stroke. They are the main health risks that we perceive to be
of great importance, and we believe banning public places from
the effects of smoking would, of course, help all the individuals
who work in those places and reduce their risk of acquiring those
diseases.
Q63 Chairman: How reliable and robust
is the evidence of harm caused by second-hand smoke?
Professor Dame Carol Black: I
think the evidence with respect to lung cancer and to heart disease
is particularly strong. I think we would have to say that the
evidence with respect to chronic bronchitis and to stroke is perhaps
less strong, but perhaps I could ask one of my colleagues to give
you the in depth detail.
Q64 Chairman: Mr Hackshaw, could
you tell us how the estimates are arrived as well?
Dr Hackshaw: The estimated number
of deaths or the increase in risk associated with the diseases?[1]
Q65 Chairman: Both.
Dr Hackshaw: First of all, the
overwhelming evidence for passive smoking disease comes from a
wealth of evidence from active smoking. If you accept that active
smoking causes diseases, then you must accept that passive smoking
is associated with some risk: because if you smoke 10 cigarettes
a day, your risk of heart disease or lung cancer or any other
number of diseases is going to be less than somebody who smokes
40 per day, and if someone smokes five a day it is less than someone
smoking 10 a day, so risk changes with increasing exposure. Passive
smoking you can think of as a mild form of active smoking, so
it must be associated with some risk. There are many studies on
active smoking. There have also been many studies in passive smoking
in non-smokers. There are over 50 on lung cancer and they consistently
show that the increase in risk is of the order of 25%. Similarly
for the studies of heart attacks: they consistently show that
the risk is of the order of about 25%. Also chronic lung disease
and similar evidence for stroke, although there are fewer studies.
Estimates of the number of deaths were published in the BMJ recently
by Professor Jamrozik. That was a simple analysis based on various
estimates of the prevalence of exposure, people who are exposed
to passive smoke, the increase in risk associated with four specific
disorders and the number of people who get lung cancer, heart
disease, stroke and chronic lung disease each year, and if those
estimates are put together in a formula you get a rough idea of
how many deaths per year you can expect.
Q66 Chairman: What is that figure?
Dr Hackshaw: The figure quoted
in the report is about 12,000.[2]
Q67 Chairman: When you use the phrase
"simple analysis", how robust is that from a scientific
point of view? Has it stood the test that science does in terms
of evidence by being overlooked, as it were, and then . . .
Dr Hackshaw: Everyone wants a
precise number, but in most things in medicine you cannot get
that, so you have a rough idea of what it may be. We know it is
going to be something of the order of a few thousand when you
put all these four disorders together. Heart disease is quite
common—about 120,000 a year get it—so intuitively
there is a feel that you might get a few thousand associated with
passive smoking. Similarly for lung cancer: the estimate the may
be a few hundred. It is difficult to get precise estimates, but
the important thing that matters is not precise estimates, it
is the order of magnitude of several thousand.
Q68 Chairman: How widely accepted
is the science that is underpinning this claims?
Dr Hackshaw: The methodology that
underpins the claims is established methods in epidemiology.
Q69 Chairman: Is it questioned by
other scientists at all?
Dr Hackshaw: Not that I am aware.
Q70 Chairman: How precisely can we
attribute the deaths solely to the effects of second-hand smoke
rather than to other environmental or lifestyle factors?
Dr Hackshaw: You are speaking
of the risk to an individual. If someone, a non-smoker, has lung
cancer and they say they have been exposed to passive smoke, the
question is: is that lung cancer due to that person's exposure
to passive smoke? The answer is that you cannot say for certain,
but that is as with many things in medicine—you cannot say
with certainty there is a risk to an individual—but we do
know that with a group of people who are exposed to passive smoke
the extra number of deaths or non-fatal diseases would be greater
than a similar group that is unexposed, so you are talking about
groups of people rather than an individual.
Q71 Dr Taylor: I think I ought to
draw attention to my declaration of interests to point out that
I am a fellow of this organisation. My reason for supporting this
inquiry is really to look at the other side: because the side
in favour of a total ban appears to be overwhelming and I hope
the inquiry is going to get some evidence from the other side
as well to get to a balanced decision. We have already heard that
95% of second-hand exposure occurs in the home. I think it was
Dr Adshead who said that. The tobacco manufacturers are claiming
that second-hand smoke is small and inconsequential compared to
other pollutants, and Dr Adshead really answered that, saying
it is indoor pollutants of which tobacco is by far the most important
and therefore the strongest; but taking all these arguments, when
the number of people affected working behind a bar is going to
be small, can we justify the sweeping legislation that you are
advocating?
Professor Dame Carol Black: Yes,
I think we can. A partial ban will really not be of any help to
us at all. The fact is that if we could make these places smoke-free,
we would be helping people to give up. We know that. We know that
there is that evidence, and you only have to look at the figures
now coming out of the Irish experience, of the reduction in smoking,
as a result of that policy. Therefore, it results not only in
the individual giving up but it results in more smoke-free homes.
There is good evidence for that. As it results in more smoke-free
homes, it helps the next generation, and our great concern is
that children should not be exposed to a smoke environment. Really
you are building up a benefit, not only to the individual smoker,
but actually within the home. I think that even though the numbers
may be small, we absolutely know it is a real risk, and I think
that there is no excuse for a partial restriction.
Q72 Dr Taylor: The aim, as has been
said before, is to affect the smoking of all the people rather
than just to attack passive smoking?
Professor Dame Carol Black: Yes,
and I think the other thing is that preventing smoking in public
places is the most certain way of narrowing the mortality gap
that we see in cardio-respiratory disease between those of high
and low income. There is nothing that this government could do
for health that would be better than to actually bring in this
ban, absolutely nothing.
Dr Edwards: Can I add a small
comment. You focused on the small numbers involved if you are
looking at the exemptions in the bar staff and so on. If you think
about bringing in regulation to prevent a proven occupational
health hazard, which this is, say you were looking at low dose
radiation: if you were looking at introducing a regulation to
proven that exposure, you would usually, I think, look at the
people who were most exposed, and if the regulation that came
in that exempted people who were most exposed—for example,
in the example of radiation you exempted radiographers and you
exempted people working in the nuclear industry—that would
be a pretty strange regulatory intervention. The present proposal
is exactly that, because there is no doubt at all, there is overwhelming
evidence, that bar staff are the most heavily exposed occupational
group and bar staff in deprived areas, which are the pubs which
people have commented on already and we have shown evidence of
that as well, the ones which are most likely to be exempted are
non-food serving and the smokiest. What you are saying is that
you are having a regulatory proposal where the people at most
risk with the heaviest exposure are exempted, and that to me does
not make any sense whatsoever. The second thing, it was mentioned
about the levels of exposure to exhaust fumes and so on. We are
doing some measurements at the moment of particulate levels in
pubs around the north-west. If you look at levels of particulates,
and the one that is particularly used is PM2.5, which is a particle
that goes down into the lungs and so it is a big health risk.
If you look at the levels in heavily trafficked roads, you may
be looking at levels of 20, 50 micrograms per cubic meter (mg/m3),
something like that. If you go into a very smoky pub—and
I can show you a graph here, if you like—we have found levels
of up to 1400 mg/m3. There is a huge difference several orders
of magnitude. So when you are talking about exposure from particles
which are known to affect health, and there are plenty of studies
to show that particulate matter affects health, some of the places
where you get the very greatest exposure is in the indoor environment
in smoky pubs, much more than you do from traffic pollution at
the road side.
Dr Taylor: That is very, very powerful.
Mike Penning: The point I was going to
make has been covered by the previous question.
Q73 Charlotte Atkins: Some organisations
would argue that the answer to all this is ventilation and that
that can deal with second-hand smoke and that this is far too
Draconian a way forward. What is your comment on that?
Professor Dame Carol Black: The
only thing you do by improving ventilation, however good your
ventilation system is, is you make the air smell rather better,
you just circulate the air around, you do nothing to take away
the carcinogens in that environment from being present. I think,
Richard, you might like to give the figures.
Dr Edwards: It is the same thing.
The team that I work with in Manchester have done a previous study
looking into about 60 pubs in Manchester and they found that there
was no significant effective ventilation on nicotine levels and
on particulate levels between the different pubs. They have just
done a study in a pub in Cannock which has put in some state of
the art filtration equipment. The particulate levels with the
filtration equipment switched off were about 800 or 900 mg/m3,
so again much higher than a heavily trafficked road, huge levels.
When the filtration equipment was put on the levels were about
500 or 600 mg/m3. You can say, yes, there is a reduction, maybe
30%, 40%, whatever the figure is, but a reduction to still a very
high level is meaningless, and there is no evidence that ventilation
reduces the level of carcinogens and the level of toxic components
in second-hand smoke to levels which would protect health, and
even the ventilation industry and the tobacco industry do not
claim that. If you look at their statements about ventilation,
they talk about improving comfort, improving the appearance of
air quality. They make no claims about health effects. None of
them has ever done that, and that is because they cannot.
Q74 Charlotte Atkins: What about
the work of DrAndrew Geens? Are you familiar with his work? I
think he comes from Glamorgan.
Dr Edwards: I am, yes.
Q75 Charlotte Atkins: What comment
would you make about his work, because he seems to imply that
it would make a difference?
Dr Edwards: He has done a study
in Manchester in one of the airport hotels there, and it is interesting.
A lot of what he presents is percentage reductions, which, as
I have said, if the levels are very high is meaningless. The other
thing is that in some of the studies that I have seen of his,
the point when the monitoring stopped was about eight o'clock
in the evening, just as the places are starting to fill up with
smokers. I am not quite sure what the reason for that is.
Q76 Charlotte Atkins: Perhaps we
ought to ask him.
Dr Edwards: As I understand it
the funding for a lot his studies comes from the tobacco industry,
so it may be there is a conflict of interest there. I think there
are an awful lot of other studies by independent scientists looking
at ventilation and it has never been shown to reduce levels to
an appropriate level to protect health. There are other problems
with ventilation. It is very expensive. For a pub it may be five,
10, 15 thousand pounds to install. If you are going to have ventilation,
then you have to maintain it. You have to switch it on. In a lot
of the pubs in Manchester that our team went round it was not
switched on. It may not be working if it is not maintained. You
have got to have a regulatory enforcement infrastructure to check
that it is working and that it is achieving air quality. If you
look at, say, the Public Places Charter, all the things about
ventilation are talking about air changes or a supply of air.
They do not talk about achieved air quality. That is what we are
interested in, because that is what causes the health effects.
Q77 Charlotte Atkins: Presumably,
if the air smells a bit better, as Professor Black is suggesting.
Dr Ashcroft: Which it probably
does.
Q78 Charlotte Atkins: Then of course
it could lull people into a false sense of security. Thank you.
Dr Hackshaw: Having separate smoking
and non-smoking areas—as many places have at the moment—also
has no effect. You can measure nicotine in the air, which is tobacco
specific, and you can measure that in smoking and non-smoking
areas and find them to be quite similar, so ventilation or non-smoking
and smoking areas do not work.
Chairman: Dr Geens did write a letter
to the Committee, not with any hard evidence, as it were, but
it is our intention to send him the transcript of the last few
minutes and invite him to comment on what has been said.
Q79 Dr Naysmith: I would like to
pull out a little bit what Dr Edwards said just now, when he said
that ventilation was "useless". You did use that word,
did you not?
Dr Edwards: It has not been shown
to reduce levels of tobacco smoke pollutants to anything like
a level that would protect against the health effects.
1 Dr Hackshaw later informed the Committee that the
estimate of risk due to ETS comes from studies of non-smokers
who were or were not exposed to ETS. There have been many studies
of lung cancer and heart disease, but fewer on stroke and chronic
bronchitis hence why the evidence is sometimes referred to as
less strong. This does not mean that there is no excess risk;
it simply indicates that there is some uncertainty over the precise
estimate of the increase in risk. Back
2
Dr Hackshaw later informed the Committee that this includes deaths
among smokers exposed to ETS and due to ETS. The number of deaths
among non-smokers is about 7,500 and using conservative assumptions
it would be about 4,000. These numbers do not include deaths from
diseases other than lung cancer, heart disease, stroke or chronic
bronchitis, nor do they include a multitude of non-fatal diseases
or childhood disorders. Back
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