Day 036 - 13 Oct 94 - Page 15


     
     1
     2   Q.   How do you grade your social classes in America -- do you
     3        give them numbers or letters?
     4        A.  There is no standard practice in that regard.
     5
     6   Q.   I am not sure we have a standard practice, but there are
     7        usually, I think -- I am not an expert -- about five
     8        grades attributed to socioeconomic status in this
     9        country.  Do you suppose that the customers of McDonald's
    10        are mostly from the top one or two socioeconomic grades,
    11        Dr. Barnard?
    12        A.  I would have no idea.
    13
    14   Q.   Nor should you; it is, perhaps, an unfair question.  Let
    15        me finish the paragraph, if I may:  "These data are not
    16        consistent with the hypothesis that high dietary fat
    17        intake increases breast cancer risk.  Indeed, they suggest
    18        a possible protective effect of high-fat intake, but this
    19        result may be influenced by methodologic problems with the
    20        dietary assessment.  These results certainly indicate the
    21        need for further exploration".  Do you agree with that
    22        last sentence as at 1987?
    23        A.  I would agree that there is a continuing need for
    24        exploration.  This study again recalls the analogy, if
    25        I may express it again -- I may have expressed it more
    26        than once before -- that when one is looking at cohort
    27        studies, one cannot -- one is making a serious error if
    28        one looks at them as, say, a poll, and if half the cohort
    29        studies or more than half identify a dietary culprit, if
    30        you will, and a minority do not, then one simply goes by
    31        the weight of the numbers.  That is not the way that these
    32        results can be used because of the methodologic problems
    33        which you cited on page 469.
    34
    35   Q.   Yes, I deliberately drew that to your attention.
    36        A.  One will expect that many, many cohort studies will
    37        find no significant effect at all, even when a very
    38        important effect is present.  That is why I tried to use
    39        the analogy, in the hope it would be helpful, that if one
    40        sends, say, 20 search parties into the woods and 15 of
    41        them come up empty handed, but five of them find exactly
    42        what you are looking for, one does not ask the 15 to vote
    43        and the five to vote and then conclude that there is
    44        nothing whatsoever in the woods.  That would be a terrible
    45        error, and any scientist who discounts negative cohort
    46        studies as evidence that this relationship simply does not
    47        exist is making a misinterpretation.
    48
    49   Q.   Oh, yes, Dr. Barnard, perhaps you have not properly
    50        understood what may be the issue in this court and 
    51        eventually what the issue is will be determined by his 
    52        Lordship's rulings on various matters (with which you need 
    53        not be concerned).  Assume for the moment that it is not
    54        part of my purpose to establish positively a negative;
    55        assume that it is not my purpose to establish that the
    56        links between diet and cancer, such as the evidence shows
    57        them to be, are not causal.
    58        A.  Yes.
    59
    60   Q.   Do you understand?

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