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

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