Day 023 - 13 Sep 94 - Page 10


     
     1        rather than younger; the older you are when you have your
     2        first child, the greater the risk you have of developing
     3        breast cancer.  Also there appears to be a protective
     4        effect if you have more children rather than fewer
     5        children.  Again this is something which, you know, fewer
     6        children are seen in developed countries because couples
     7        work.  There are social factors other than dietary
     8        factors.  So, yes, there are cancers where, like breast
     9        cancer, other factors than diet have been implicated to
    10        explain the differences which occur in different parts of
    11        the world.
    12
    13   Q.   What about colon cancer?
    14        A.  Well, this again is more difficult to know but, as we
    15        were saying yesterday, there may be some genetic factor
    16        which we understand poorly.  Polyposis coli, this
    17        genetically determined condition is something which one
    18        tends to see in western countries, though this may be a
    19        problem of information retrieval rather than anything
    20        else, because we also said yesterday in under-developed
    21        countries their information systems are not so good.
    22
    23        Colon cancer is the great enigma, in that people have
    24        argued just about everything as being involved in the
    25        causation of colon cancer, but the honest answer to it all
    26        is that we do not know.
    27
    28   Q.   But the alternative you are putting forward to diet is
    29        genetics in terms of colon cancer?
    30        A.  As I said yesterday, we do know that if -- say your
    31        mother had developed colon cancer, the risk of you
    32        developing colon cancer would be increased at least two to
    33        four fold, which is a substantial increase.  Now, we
    34        cannot actually identify a specific genetic abnormality to
    35        account for that, but this relationship is so consistent.
    36
    37   Q.   But it could equally be that my mother teaches me how to
    38        cook and what sorts of things to eat?
    39        A.  The relationship is irrespective of dietary patterns.
    40        People have looked at this and tried to say, "It is this.
    41        If you are used to a high fat diet, the same risks will
    42        act on you and your mother".  But they have also looked at
    43        people with so-called "low risk diets".  This relationship
    44        still stands.  There is an increased risk of a blood
    45        relative getting cancer if another one has developed
    46        cancer at some time in the past.
    47
    48   Q.   There is also the migration studies where people live in a
    49        country with low a risk, migrate to a country with a
    50        higher risk where there has not been any history before 
    51        they start ----- 
    52        A.  But the other factor is that it is not only diet that 
    53        changes when people move to these countries, their
    54        lifestyle changes.  There is an interaction of factors
    55        here.  Diet may be one -- I am not saying it is not -- but
    56        it is not as straightforward as only diet being implicated
    57        in what happens to people when they move countries.
    58
    59   Q.   What studies have indicated other lifestyle factors apart
    60        from diet?

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