Day 254 - 22 May 96 - Page 34
1 statistical analysis.
2
3 MR. MORRIS: Can I say, just before we move off the study, the
4 conclusion at the end is about: "Unlikely that a reduction
5 in total fat consumption by middle aged and older women
6 will substantially reduce their risk of breast cancer".
7 That is after all the variables have been taken away, like
8 the fibre consumption, and the body mass index, and all
9 those age at menarche; yes?
10 A. What they have done is they have allowed for these
11 other variables in their analysis. What they are doing is
12 they will get groups of women who had a menarche at a
13 certain age, who have developed breast cancer subsequently,
14 and a group of women of menarche at the same age who have
15 not, and they will be compared.
16
17 What they are actually doing is trying to relate all of
18 these other factors to one another so that they get equal
19 groups of women in the final analysis to try to exclude
20 what influence these other variables might have on the risk
21 of developing breast cancer. At the end of the day, the
22 single variable that remains is fat intake. They make the
23 comment in the paper about the amount of computing time
24 that was needed for this. It is a complex issue.
25
26 MR. JUSTICE BELL: Yes. Is there anything more on that article?
27
28 MS. STEEL: Not on the actual document itself.
29
30 (To the witness): Where you say on page 5 of your
31 statement referring to the study that:
32
33 "The authors rightly point out that the deficiencies of
34 dietary analysis and methodological problems associated
35 with international case control studies and also indicate
36 that prospective studies too have been criticised as
37 misleading because of the size of individual studies, the
38 limited range of fat intake, and the population studied and
39 miss-classifications of fat intake", they were only
40 examining in this paper the cohort studies, were they not?
41 A. They were. I think they fairly point out they are
42 trying to be impartial too. I do not think they have a
43 particular axe to grind. They are pointing out the
44 limitations of the studies as they exist today, not only
45 the international population studies, the case control
46 studies, but also the cohort studies. I think they are
47 being very fair in that respect.
48
49 MR. JUSTICE BELL: Some of the confounding variables, presumably
50 the Gold Standard, as I think they call it, is more
51 reliable than others anyway?
52 A. Yes.
53
54 Q. People's accounts of their alcohol intake are notoriously
55 unreliable but they all know whether they have got to
56 graduation and whether they went beyond the regulation?
57 A. Indeed yes.
58
59 MS. STEEL: On page 6 of your statement, the first paragraph,
60 where you talk about:
