Day 017 - 25 Jul 94 - Page 33


     
     1        experiments by Kritchevsky and, indeed, I think somebody
              called Alvarnes (?) as well noticed that caloric intake
     2        seemed to be more effective than fat in tumour promotion
               ------
     3        A.  Yes, they actually gave rats different diets; one with
              high calories and low fat and one with high fat and -----
     4
         Q.   At the top of 595, one sees that.  A Low fat -----
     5        A.  A low fat, high calorie diet and a high fat, low
              calorie diet, and it was the caloric reduction which
     6        inhibited the growth of mammary tumours in the rats.
 
     7   Q.   Despite the high fat?
              A.  Despite the high fat.
     8
         Q.   Then there is a section about fat and other cancers:
     9        Large bowel cancer.  I will leave that since we are going
              to come on to that in due course.  I want to go to the top
    10        of page 596, just above the Conclusion.  "Despite
              plausible theoretical mechanisms the positive geographical
    11        correlations and the results of animal experiments and the
              human evidence for fat as a cause of large bowel cancer
    12        remains weak."  Do you agree with that or not?
              A.  I would agree with that, yes.
    13
         Q.   "The similarity in geographical correlations with fat
    14        between colon and breast cancers may be coincidental,
              though the lack of reliable international data makes it
    15        difficult to evaluate one possible explanation, namely,
              the postulated protective role in colon cancer of
    16        non-starch polysaccharides (fibre).
 
    17        Conclusion:  The evidence for fat as a cause of breast
              cancer has been exaggerated, with crude geographical
    18        correlations holding sway over the findings of
              individual-based studies, counter to the accepted
    19        hierarchy for such types of evidence."
 
    20        Dr. Arnott, is there a hierarchy?  You started with
              cohorts at the top and here we find Dr. Kinlen putting
    21        individual case control studies next and populations
              studies at the bottom; is that a hierarchy you agree with?
    22        A.  Yes, certainly cohort studies are the most reliable;
              case control are intermediate and the population studies
    23        are open to so many problems of interpretation that
              I think they have the least value.
    24
         Q.   Dr. Kinlen says:  "The present case does not seem to
    25        warrant such an exception.  The work most often quoted in
              support in fact stressed the weaknesses of international 
    26        correlations, and cautioned that they 'should be taken 
              only as suggestions for further research and not as 
    27        evidence of causation or as bases for preventative
              action'."  Can I take it that comes from Armstrong and
    28        Doll?
              A.  That is the Armstrong and Doll paper.
    29
         Q.   Can we skip the next part and start halfway down the
    30        penultimate paragraph.  Do you see the words:  "We lack
              any good evidence".  Do you have that?  After two words at

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