Day 036 - 13 Oct 94 - Page 17


     
     1        distorted if they do not exclude these special factors?
     2        A.  It is important to be as specific as possible.
     3
     4   Q.   Tab 24, please, Dr. Barnard:  We have moved forward five
     5        years to 1992.  I hope that I am going to find -- I am
     6        doing this chronologically because I think that may be
     7        important -- a paper by Lawrence Kushi?
     8        A.  Pronounced Kushi.
     9
    10   Q.   Is he a well known figure in this field?
    11        A.  Yes, he is.
    12
    13   Q.   He is from the University of Minnesota; is that right?
    14        A.  Yes, he is.
    15
    16   Q.   Though the whole team does not come from Minnesota; one of
    17        them it looks as though he came from the Iowa College of
    18        Medicine, University of Iowa; roughly speaking, the same
    19        part of America; never mind that.  Can I read the
    20        introduction:  "Background:  Although the results of
    21        animal studies and cross-cultural comparisons generally
    22        support a role for dietary fat in the aetiology of breast
    23        cancer, results of analytic epidemiology studies are
    24        equivocal. Purpose:  The association between dietary fat
    25        and subsequent breast cancer was examined in a cohort of
    26        34,388 postmenopausal women from Iowa. Methods:  Dietary
    27        habits were assessed by a food-frequency questionnaire
    28        mailed in January 1986.  Through December 31, 1989, 459
    29        incident cases of breast cancer occurred in this cohort.
    30        Proportional hazards regression was used to examine the
    31        dietary fat-breast cancer association while adjusting for
    32        potential confounders.  The effects on this association of
    33        four analytic approaches to adjustment for energy intake
    34        were also considered."
    35
    36        Does that mean, perhaps, we can see as we go through some
    37        parts of this document, what they did was to apply four
    38        different kinds of analytic methodology to the results
    39        which they obtained?
    40        A.  Yes, that is correct.
    41
    42   Q.   "Results:  After adjustment for known determinants of
    43        breast cancer, a modest positive association of total fat
    44        intake with risk of breast cancer was seen.
    45        Polyunsaturated fat intake was also positively associated
    46        with breast cancer (relative risks from lowest to highest
    47        intake, 1.0, 1.25, 1.31, and 1.49 ...).  Different
    48        approaches to adjustment for energy intake, however,
    49        provided different impressions of the dietary fat-breast
    50        cancer association.  One method, involving categorization 
    51        of crude fat intake and inclusion of total energy intake 
    52        in regression analysis, gave relative risk estimates from 
    53        low to high fat intake of 1.0, 1.17, 1.25, and 1.38 ...
    54        Another method, based on categorization of fat intake
    55        residuals in which the variation in fat due to total
    56        energy intake was removed, gave corresponding estimates of
    57        1.0, 1.24, 1.30, and 1.16 ...   The former suggests
    58        increasing breast cancer risk with increasing fat intake;
    59        the latter suggests no association.  Conclusions: These
    60        results are consistent with other cohort studies that have

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