Day 017 - 25 Jul 94 - Page 07

     
     1        identify accurately a cause and effect.
 
     2        Now, in some instances one may see such a radical change
              that it is quite obvious that there is a cause and effect
     3        relationship.
 
     4   Q.   Take an example, from a layman's mind, what about tobacco
              smoking?
     5        A.  Yes.  One could take cigarette smoking, for example.
              The original studies that were carried out on this were on
     6        British doctors.  The British doctors were asked by
              questionnaire whether they smoked or not.  The purpose of
     7        this particular study was to try to get a group of doctors
              of a certain age characteristic and match those with
     8        people who did not smoke, then find out what happened to
              them.  There we found that people who smoked were dying of
     9        lung cancer.  The relationship was so strong that one
              could not escape from the inevitable conclusion that
    10        cigarettes were in some way or another related to the
              death of these people from lung cancer.
    11
              The point about that study is that it was set up at a time
    12        when we did not know whether cigarettes had any harmful
              effects or not.  This was an unexpected finding, this
    13        question of death from lung cancer.  One of the advantages
              of the study was that it could not introduce bias.  You
    14        could say there was some bias in that you are only looking
              at British doctors -- these, of course, are not
    15        representative of the population as a whole -- but at
              least you were able to compare similar people smoking and
    16        not smoking.  That relationship was so strong one could
              not escape from the inevitable connection between the two,
    17        although it did not actually identify at that particular
              time what it was in cigarettes which caused the cancer.
    18
         Q.   That was about when, that study; in the 50s?
    19        A.  Yes.
 
    20   Q.   About 1955/56?
              A.  Mid 50s.
    21
         Q.   By Sir Richard Doll?
    22        A.  Yes.
 
    23   Q.   What is the position today so far as what I might call
              informed scientific opinion is concerned in relation to
    24        cigarette smoking and lung cancer?  Has it advanced since
              1955/56?
    25        A.  I think it has advanced in the sense that the evidence
              has become much more concrete.  There have been further 
    26        follow up studies, not just looking at select groups of a 
              population, but also looking at a wider population, and 
    27        the results reproducible.  There are also substances which
              have been identified in the tar of cigarettes, or in what
    28        comes out in the smoke which are, in fact, various forms
              of tars, which when painted on skin of animals cause
    29        cancers.  So it is likely (and we believe this to be the
              case, though it is very difficult to be absolutely
    30        specific) but we believe that it is likely that it is the
              tars contained in the cigarette smoke which cause the