Day 022 - 12 Sep 94 - Page 45
1 menstruate. That is why you can identify certain factors
2 as being important in relationship to breast cancer,
3 because these are factors which do cause major hormonal
4 changes within the body.
5 We do know that breast cancer is an hormonally influenced
6 tumour because that is often how we treat breast cancer.
7 We modify the hormone environment of the body. We change
8 it in some way by giving hormones or removing hormones.
9
10 So, by the time the person starts to menstruate, giving
11 birth to children, the number of children, and also the
12 time at which the person has the menopause, these are all
13 major periods as far as hormonal changes are concerned.
14
15 Q. Just on that subject, say, breast cancer: If you are
16 looking at dietary considerations in cohort studies, they
17 really should go back to that period, that very early
18 period, to be sure whether they are having an effect or
19 not having an effect?
20 A. Often cohort studies do encompass a large number of
21 people, not all of them by any means, like the nurses
22 study did not go back to childhood, but some studies have
23 looked at populations including young people.
24
25 Q. But have they studied people from the age of when they
26 were children to the age of when they developed cancers,
27 say, some 20 to 30 years?
28 A. Some studies have done that, yes.
29
30 Q. They have done that?
31 A. Yes.
32
33 Q. Are they the ones in your references?
34 A. Yes, I think it is a Norwegian study which looked at
35 deprivation of women -- well, looked at the incidence of
36 breast cancer, and one of the conclusions that they came
37 to was that energy restriction at the time when the
38 children were small, you know, they were developing, may
39 play a factor, maybe a factor, in reducing the risk of
40 breast cancer at a later time.
41
42 Q. So ----
43 A. But many studies -----
44
45 Q. But most cohort studies, presumably, that have been done
46 have not ---
47 A. No.
48
49 Q. -- gone into that great length of time, 20, 30, 40 years?
50 A. Well, they have gone in for 20 years, or some of them
51 have, but they have looked at people who were adult at the
52 time they were recruited into the study.
53
54 Q. Right. Presumably, for other cancers -- I mean, breast
55 cancer may be connected, it is thought, to particularly
56 young girls and it may develop at an early stage and can
57 be related, but other cancers -----
58 A. We do not know this.
59
60 Q. No, but all I am saying is that other cancers may have
