Day 022 - 12 Sep 94 - Page 17
1 and the National Research Council paper in 1982?
2 A. Which are old papers.
3
4 Q. I was going to ask: They qualify as old, do they?
5 A. I think so. One of the problems in a lot of the
6 studies which were originally carried out was that some of
7 them were analyses of papers which were already in
8 existence. If one reads a lot of the papers on trying to
9 estimate what diet is, going back to the 1970s, the
10 authors of these papers actually state clearly that the
11 methodology was actually in its infancy at that time. And
12 there is no doubt about it that in recent years
13 methodology has improved and also people have begun to
14 realise the problems of bias that might creep in with the
15 so-called case control studies; in other words, the
16 retrospective analyses where you look at a group of people
17 who have cancer, and you try to match them with a group of
18 people who do not have cancer. These are studies which
19 are particularly open to bias.
20
21 Therefore, people have tried to run the so-called
22 prospective epidemiological studies where they take two
23 groups of people who are healthy at the time the study
24 starts, and then follow them through the years to see what
25 sorts of illnesses these people develop. They, therefore,
26 look at their dietary intakes at the beginning of the
27 studies. This means that the diet these people describe
28 is much less likely to be influenced by factors such as
29 illness or enthusiasm, which is a danger of the case
30 control studies, that the control group often are
31 enthusiastic people. The other difficulty with controlled
32 studies is that it is often done on a mail shot basis.
33 They send a questionnaire around to several hundreds or
34 thousands of people sometimes. There is a poor
35 recruitment rate. In other words, in some studies, only
36 55 per cent of the people to whom a questionnaire is sent
37 actually respond.
38
39 This immediately raises doubts about the validity of the
40 study of that nature.
41
42 MR. MORRIS: I think we will come later to specific methodology
43 and have a look at them and compare. I am just trying to
44 look at what, you know, responsible bodies are saying. If
45 we go on to the ones I have given to you by hand? You can
46 put the Grey Book away now. Thank you very much. If we
47 look at the one that is headed: "NATO Advanced Research
48 Workshop on Advanced Technologies". NATO, presumably, is
49 North Atlantic Treaty Organisation. Something intrigued
50 me -- do they have these kinds of conferences that look
51 into nutritional matters? I was surprised when I saw
52 that.
53 A. I have to say I was not aware of that, but -----
54
55 Q. All right. So some countries ----?
56 A. I mean, nutrition is obviously something which is of
57 great interest to a lot of people and a number of
58 organisations are quite likely to have the facilities
59 therefore to organise a congress such as NATO may have
60 done.
