Select Committee on Health Minutes of Evidence

Examination of Witnesses (Questions 169-179)

26 JUNE 2003


  Chairman: Colleagues, could I welcome you to this session of the Committee and welcome our witnesses. Before we begin, could I welcome Paul Burstow, who is making his debut at the Committee today: we are very pleased to see you here. I think it is appropriate to pay tribute to your predecessor Sandra Gidley, who was a first-class member of the Committee who was responsible for initiating certain inquiries. We are very grateful for her efforts. I am sure you will follow her lead in many ways. We are very pleased to see you here.

  Dr Taylor: May I add my comments. I appreciate her work as a pharmacist. I think in government as a whole there is a lack of professionals in positions of authority.

  Chairman: Apart from lawyers, of course!

  John Austin: And teachers.

  Jim Dowd: Lawyers, lecturers and social workers.

  Q169  Chairman: Thank you. Could I ask the witnesses briefly to introduce themselves to the Committee.

  Dr Barrett: I am Dr Timothy Barrett. I am a paediatrician at Birmingham Children's Hospital, responsible for a clinic of about 350 children with diabetes and I am a senior lecturer in the University of Birmingham doing research into diabetes and genetics.

  Dr Rayner: My name is Geof Rayner. I am Chair of the UK Public Health Association but also representing the Faculty of Public Health Royal College of Physicians.

  Professor Peto: I am Julian Peto, Head of Epidemiology at the Institute of Cancer Research and I also have a part-time Chair at the London School of Hygiene and Tropical Medicine.

  Professor Lacey: My name is Hubert Lacey. I am Professor of Psychiatry at St George's. I run the St George's Eating Disorder Service. It is not only the largest in the UK but probably the largest in the English speaking world. It deals mainly with anorexia and bulimia nervosa—with a small offshoot into obesity, because of lack of funding.

  Professor Wardle: I am Jane Wardle. I am Professor of Clinical Psychology in the Department of Epidemiology and Public Health at University College and I am Director of Cancer Research UK's Health Behaviour Unit there. As part of my role there, I do research into obesity, including beginning to run some treatment studies for paediatric obesity.

  Professor Sir George Alberti: I am George Alberti. I am emeritus Professor of Medicine, Newcastle, and Senior Research Fellow at Imperial College. I am also the Trolley Tsar—sorry, the National Director for Emergencies Access, and President of the International Diabetes Federation. I have worked in diabetes for the last several decades, and also ran a very unsuccessful obesity clinic for many years!

  Q170  Chairman: Obviously, from the evidence we have had from a range of witnesses, the obesity problem has been something that has been emerging for some considerable time. Why has it taken so long for us to wake up politically to address the issue?

  Professor Sir George Alberti: I suppose because it has insidiously crept in. My own experience, talking to an ex-minister while she was a minister, is that she did not want to know. She did not want to tell the public a very simple thing: "Eat less." That did not seem to be a great vote-catcher. Medically I think we have been enormously unsuccessful at altering people's habits and it has just sort of crept in. It is only as we have begun to see epidemics of the consequential diseases that it has really begun to grab hold of people.

  Q171  Chairman: You are saying that it is a politically difficult issue for governments to address.

  Professor Sir George Alberti: Yes.

  Q172  Chairman: For the reasons you gave.

  Professor Sir George Alberti: Yes.

  Professor Lacey: I think there is another clinical reason, Chairman, which is that as a group clinically they are not liked: people do not find them attractive to work with. They are often subject to stigma, not only from the general population but also, to a degree, from professionals too. I would agree with Professor Alberti, the other reason professionally is that they are very difficult to respond to treatment.

  Dr Rayner: I would add that I think it is society looking at itself, really. We are talking about basically the medical consequences. Obesity and super-obesity, but overweight as well, these are consequences of changes in society. We are actually very poor at recognising the powerful cultural change that has happened in this country. And it is happening worldwide. We are not talking just about a UK epidemic. All the reasons that you have been presented with, from changes in dietary patterns to the reduction of physical activity, these are big changes in society. We need big explanations. When you have big explanations which you cannot pinpoint exactly then it is very difficult to see what you can do about it. What do we do about it? If there was a magic pill or bullet or something, but there is not, so we actually have to face up to these big cultural changes and we do not have solutions. We call it a lifestyle illness or lifestyle pattern which explains it, but actually it is our society changing. How do we deal with that?

  Professor Peto: In relation to cancer, cancers tend to be studied individually because the causes of different cancers tend to be different. Although it has been known for a long time that breast cancer and endometrial cancer are associated with obesity, it was not until quite recently, when very large American cohort studies, particularly studies of non-smokers, were done, that it was realised what a large contribution overall cancer mortality was making to the effects of obesity, that a whole range of cancers are actually affected. The risks are not huge, and they only emerge in very large studies, but in this particular one, a very large cohort study, it has emerged quite suddenly that among non-smokers obesity was by far the largest avoidable cause of cancer. Heart disease and diabetes obviously have been recognised for a long time, but the realisation that it was a major contribution to cancer has really only emerged quite recently.

  Q173  Chairman: We will obviously talk about the public health sector later on and public health steps that might be taken, but, looking back at how the trends have emerged over the years, what ideally might have happened, say, some years ago that could have prevented us being where we are now? What should have happened and at what point? Who should have been responsible for doing something?

  Professor Sir George Alberti: I think a massive public education programme—there is one, it has got through to a few people, but I think it has never been emphasised adequately—and tackling the food industry head on.

  Chairman: We will get into the specifics later on, so perhaps we should not pursue that further.

  Q174  Julia Drown: I want to ask Sir George Alberti about diabetes in particular. Obviously we are seeing huge increases in the number of people with diabetes. Could you briefly outline to us what the evidence is on the role of weight gain in diabetes and whether that is disputed or generally accepted.

  Professor Sir George Alberti: Number 1, it is generally accepted. We have seen worldwide, in a number of societies, a parallel increase in overweight, obesity and diabetes. Just as an example, I have studied diabetes and obesity in East Africa—as one does—and in the rural areas there were less than 1% of people over the age of 15 with diabetes and less than 2% overweight. Move into the city, and we are up to 20-25% overweight and 8% diabetes: an eight-fold increase. Some of the populations who have become wealthy very rapidly, like the American Indians in Arizona, where they were given the worst bit of land, as you know, oil wells were found, so they became very wealthy, stopped working, became very overweight, and half the adults in that population have diabetes. It is the same on the South Sea island of Nauru, which was basically a large coral reef of bird droppings, which was mined as fertiliser. Overnight, in the fifties, it became the second richest country in the world and the people are very overweight, life expectancy is falling, and diabetes is the main accompaniment of that. You cannot separate it completely from physical inactivity. Each of them, independently, has a two-, three-, four-fold increase in risk. There was a very good prospective study of nurses in the United States which showed that, if your body mass index was 22 (that is, nice and skinny like I am) and you compared yourself with those people with a body mass index of 35 (which is pretty obese), there was a 92-fold increase in risk of diabetes. I think it is very, very solid. With the additional impact of physical activity, which is probably equally important—or physical inactivity. Society is pushing both physical inactivity and overeating as well, or eating the wrong things.

  Q175  Dr Taylor: Could we go back to the links between obesity and cancer, really to Professor Peto—and I must say that the paper we have had from Cancer Research—which is precisely one side of a sheet of paper—is absolutely splendid because it is the sort of length that we can actually digest. This does tell us that about one in eight of cancer deaths in non-smokers is due to being overweight or obese, so it is a real problem. It also goes on,"... the link between obesity and cancer has been poorly acknowledged." Could you give us any idea of the mechanisms of this link? Is that a possible question or just not known?

  Professor Peto: One straightforward one is that there is a correlation between obesity and circulating levels of things that are associated with cancer risk. I mean, hormones—oestrogen, particularly in post-menopausal women, which certainly would contribute to breast and cancer of the uterus. Insulin, of course, in relation to diabetes. What its relation to cancer is, I do not know, but IGF-1 (insulin-like growth-factor type 1) is emerging as an important circulating correlate of cancer risk for a whole range of cancers. That is correlated with obesity. So there are endogenous processes associated with obesity which certainly correlate with cancer risk in the general population. In relation to oesophageal cancer, which is quite an important cancer, there is gastro-oesophageal reflux which is likely to increase the risk of oesophageal cancer. Cancer of the gall bladder is trivial, but gall stones are associated with obesity and with cancer, so in that particular site there is a plausible mechanism. We are talking about cancer mortality not incidence and the relationship with obesity seems to be stronger with the death rate than with the incidence rate. The reason for that is probably that very obese people are diagnosed late. Whether or not, once the cancer is there, obesity has any effect on the course of the cancer is not known, but they are certainly likely to be diagnosed late—there is direct evidence of that—and, once you have got cancer, you are more likely to die of it if you are obese because you are diagnosed at a more advanced stage.

  Q176  Dr Taylor: That brings us back, I think, to the point Professor Lacey raised, that doctors as a whole probably are less interested in the really obese and they are more difficult to examine.

  Professor Peto: I think they are more difficult to examine. I do not think doctors do not examine them because they are not interested in them, I think that would be going a bit far. But, I mean, you are a doctor, there is . . .

  Q177  Dr Taylor: Yes.

  Professor Peto: There is one other point which may not be negligible: excess energy. First of all, increased body size. One might expect it to be associated with cancer on arm-waving grounds: cancer originates in a single cell; if there are more cells dividing more quickly, you might expect the cancer rate to be increased. That is an arm-waving argument. It probably has some validity. Of course, in relation to colon or rectal cancer, it is pretty obvious that the chemistry of stools is affected by what you eat and whether you overeat. Again, there is an arm-waving argument. The explanations range from being really rather specific and well-established, to being speculative and plausible. But they are scientifically reasonable.

  Q178  Dr Taylor: So you have mentioned the breast, endometrial cancer, oesophageal cancer, colonic cancer. Other cancers?

  Professor Peto: Cancer of the oesophagus, you mentioned that. That is an important one. I do not know whether the insulin relationship has anything to do with the pancreas, but pancreatic cancer has emerged consistently in studies as being linked to obesity. The one important cancer where the evidence is, I suppose, dubious and I think it is probably more likely to be due to survival than incidence, is prostate cancer. There is a significant link with prostate cancer in a big American study, but it is not clear whether that is ... That is not as marked as the other ones, although it is statistically significant. It remains to be seen whether that is a real effect.

  Q179  Dr Taylor: Is the link generally with obesity or is there any link with people who suddenly put on a vast amount of weight?

  Professor Peto: The data on that are really inadequate. It is not known. There is not very good evidence that losing weight rapidly reduces the cancer risk. I mean, that is irrelevant from a public health—

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