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Ch.6 The Greatest Fraud
Fluoridation: Errors and Omissions in Experimental Trials - 2b CRITICISMS AND COMMENTS [cont.] DR R. M. GRAINGER by Dr. Philip R.N.
Sutton from fluoridationfacts.com
Errors and Omissions in Experimental Trials - 2b
CRITICISMS AND COMMENTS [cont.]
DR R. M. GRAINGER
The third review of this book in the
Australian Dental Journal, by DR R. M. GRAINGER, Division of Dental
Research, Faculty of Dentistry University of Toronto, was as follows:
Those whose work has been so unfairly
criticized might well ask P. R. N. Sutton if he feels his own work is
proof that the unimpeachable study can be done(26), or if he would
welcome similar scrutiny of his publications.
While we do not claim to be able to
answer every question to P R. N. Sutton's satisfaction (or even our own),
in order to help set the record as straight as possible(27) the following
are specific comments on points raised by P. R. N. Sutton in his
discussion of the Brantford Study. No attempt is made to rationalize why
specific workers directed or restricted their research efforts or
discussion in any areas other than to comment that they no doubt
accomplished as much as they could under the circumstances in which they
had to work.
Item 1: Reference to Hutton et al. (1951). The numbers of
children of the same age examined in the years 1944 and 1945 were very
similar with the exception of the nine-year age group. From the
unpublished data released at annual meetings in Brantford the number of
children examined in 1944 was 239, and in 1945, 319; making a total of
558 (not 608). The data in Table I (Hutton et al.) were apparently combined by pooling the two years'
results not by averaging the averages. However, the point is rather
academic(28).
Item 2 : Reference to Ontario Health
Department report. The date of water-fluoridation in Tables I and 11 was
given as 1946 through a typographical error but was twice correctly
stated to be June, 1945, in the text referring to the Table. The small
error in percentage reduction for seven-year-olds was also conceded.
These points do not seriously underline the usefulness of the work(29).
Item 3: Re late commencement of National
Health and Welfare study and detection of caries protection for young
individuals born prior to commencement of fluoridation. Despite the fact
that the Department of National Health and Welfare began its control
study nearly three years after fluoridation began, much worthwhile
information was obtained and the effect of late commencement, if any, was
to result in underestimation of the fluoride protection(30).
Item 4: Reason for selection of control
cities. It seems clear that Brown (1951) gave adequate reasons for
selecting Sarnia and Brantford(31).
Item 5: Re superior dental care in
Brantford. The difference in level of dental care between the cities is
factual as recorded by Brown (1952). This variation of numbers of teeth
classified as F. rather than D. or M. does not fundamentally influence
the DMF rate(32).
Item 6: Comparability of rates. As
stated under item 5, the dental condition of the children in Sarnia and
Brantford differed in 1948 because a lower level of dental treatment in
Sarnia resulted in higher tooth mortality. The tooth mortality rates thus
differed but it does not follow that the DMF rates differed(33). Brown's
statement (1951) "by 1948 the Brantford data were not greatly
different from those in Sarnia" is obviously referring to DMF rates
and hence quite valid(34). The differences in oral hygiene are also only
remotely related to the DMF rates under discussion(35).
Item 7: Concentration of fluorides. The
fluoride content of the Brantford water supply was raised to
approximately 1 ppm in June, 1945, and raised to 1.2 in February,
1949(36) The Stratford water fluoride content is believed to have been in
the order of 1.3 to 1.6 ppm since 1917 when the wells were drilled.
Naturally no analysis for fluoride was available prior to the beginning
of the interest in fluoridation and early techniques for analysis were
not as reliable as present methods(37). These facts have been recorded in
the writings of the primary workers (Hutton et al., 1951; and Brown et
al., 1951, 1952, 1953, 1954, 1956) and the differences in amounts
from other writers night seem less "strange" if they were
merely acknowledged to be minor misquotations(38).
Item 8: Re statement by Brown et al. (1956). The statement is
substantially correct with the exception that Brown's observational
period did not begin until 1948 hence is less than 10 years(39). The
decrease in mean df rates for the 9-11 years group in Sarnia between
years 1948 and 1954 (Brown, 1956), did not continue into 1955(40). There
was a highly significant decrease over the period 1948 to 1955 (2.37 to
1.93) in Brantford and no significant decrease in Sarnia (2.50 to
2.31)(41). In the same periods the mean df rates for this age [in]
Stratford remained nearly equal (1.66 and 1.65) and increased for other
ages (42).
Item 9: Re Table II: Ontario Department
of Health Report. The printing of dashes rather than percentages for the
control cities was to avoid confusing the table With "negative
reductions" and in the case of the 9 to 11 df figure to avoid
emphasising what was considered to be a spurious decrease(43). This
judgment was borne out by the 1955 figures(44).
Item 10: Differences in reported rates
between examiners. Different examiners give characteristically higher or
lower rates upon examining the same individuals due to differences in
skill, training the physical condition. Thus the differences quoted are
no reflection on the design of the experiment or the care taken in the
work. The strength of the double examinations comes through corroboration
of caries trends in Brantford over the years and not through
interchangeability of data(45).
Item 11: Significant fluctuations in
controls. The important point is that for the controls the inter-year
changes were upward trends or mere fluctuations (even though in some
cases calculated to be beyond change), whereas in Brantford the change
took the form of a highly significant continual downward trend(46).
Item 12: Larger percentage changes in
control. There is no definite explanation as to why rates increased in
Stratford and also in Sarnia over the ten years, but this may be a
reflection of a general post-war increase in dental caries which has been
seen in other areas. However, it is significant that in the various
fluoridation experiments, e.g. in Brantford, Newburgh, Grand Rapids,
etc., the shift has always been significantly downward in the fluoridated
cities whereas the control city rates have remained about the same or in
the case of Stratford, increased(47).
Item 13: Smaller percentage decrease
after longer fluoridation. As pointed out by Sutton himself on page 168
(middle paragraph) the fluoride protection for permanent teeth of the
children aged six to seven seemed to occur within two or three years
after fluoridation began. Thereafter the yearly DMF rates were subject to
random fluctuation and the differences in percentage decrease of 69 per
cent and 51 per cent are most likely a reflection of this inter-year
variation(48).
Item 14: The quotation from the Ontario
Government Report is taken out of context from a series of summary
statements. The previous statement was to the effect that in Brantford
there had been a significant decrease of about 60 per cent in DMF rates.
In the statement following, as picked out by Sutton, it was stated that
"no change" occurred in Stratford and Sarnia(49). It should be
clear enough from the context that the words "no similar downward
change" were inferred(50).
Item 15: Possible weighting effect. The
critic is referring to a possible shift in age distribution within the
group, e.g. a possible sampling shift within the six to eight-year age
group so that certain years had disproportionately higher or lower numbers
of eight-year-olds and hence higher or lower average caries scores. This
is rather remote in that selection methods used by Dr Brown were the same
each year, moreover very large shifts in age distribution would be needed
to produce the significant differences to which P N. R. Sutton
refers(51).
Commentary on the Review by Dr
R. M. Grainger
(26) Dr R. M. Grainger raises the
question as to whether "the unimpeachable study can be done".
This is, of course, unlikely. It is precisely for this reason that all
papers (and these include my own) which set out to present new knowledge
should be examined, in order to reduce the chance that findings which are
not soundly based will be accepted at their face value. This is
particularly necessary in those studies which may involve the health of
the public.
(27) The result of Dr Grainger's attempt
"to help set the record as straight as possible" will be judged
after considering his other remarks.
(28) Item 1, Reference to Hutton et al. (1951); The numbers of
children of the same age examined in the years 1944 and 1945 were very
similar with the exception of the nine-year age group. From the
unpublished data released at annual meetings in Brantford the number of
children examined in 1944 was 239, and in 1945, 319; making a total of
558 (not 608). The data in Table I (Hutton et al.) were apparently combined by pooling the two years'
results not by averaging the averages. However, the point is rather
academic.
Comment.
The phrase "making total of 558 (not 608)" suggests that the
figure 608 was an error in this monograph. This is not the case, in fact
this figure was not mentioned. It was published by the authors of this
study, Hutton et al., in 1951
(Table 1, column 2). Dr Grainger, therefore, is suggesting that the total
558 children (derived from the unpublished figures of 239 and 319) is
correct, and that the figure of 608 children examined, published by the
authors of the study, is incorrect. It should be noted that, five years
after this figure of 608 was first published, in Table II, column 2, of
their final report Hutton et al.
(1956) again published their figure of 608. In both the tables in which
it appears it has been used in computing the def and the DMF rates. Also,
if one accepted Dr Grainger's figure of 558 as the correct number of
nine-year-old children examined in these two years, the impossible
situation would also have to be accepted in which the number of these
children with decayed, missing or filled teeth, which Hutton et al. (1951) gave as 595, would
exceed the number of children examined.
(29) Item 2: Reference to Ontario Health
Department report. The date of water-fluoridation in Tables I and II was
given as 1946 through a typographical error but was twice correctly
stated to be June, 1945, in the text referring to the Table. The small
error in percentage reduction for seven-year-olds was also conceded.
These points do not seriously undermine the usefulness of the work.
Comment.
The "small" error in percentage reduction, which, Dr Grainger
said "was also conceded", was the showing of 51 per cent
instead of 66 per cent (p. 167). Dr Grainger does not mention here the
substitution of dashes for figures in the two cases of reduction in the
caries rate in the control cities (pp. 4, 37, 44). Several types of errors
are present in Tables I and 11: (a) two omissions, which Dr Grainger
implied-Item 9 of this review(43)-were made deliberately; (b) two
typographical errors; (c) two arithmetical errors (Table I, age 7,
"% Reduction Since 1944-45" in the caries attack rates should
be 66, not 51, and in Table II, age 10, the "% Reduction Since
1944" in the caries attack rates should be 18, not 61); and if, as
appears likely, the figures given by Dr Grainger in Item 1, of this
review(28), are incorrect and were used, (d) four incorrect mean figures.
Dr Grainger contends that the points
which he mentioned "do not seriously undermine the usefulness of the
work"; but the occurrence, on one page alone, of all the errors and
omissions which have just been mentioned certainly undermines confidence
in the care taken in the preparation of this official report by the
anonymous "statisticians" of the Division of Medical
Statistics, Ontario Department of Health.
(30) Item 3: Re late commencement of
National Health and Welfare Study and detection of caries protection for
young individuals born prior to commencement of fluoridation. Despite the
fact that the Department of National Health and Welfare began its control
study nearly three years after fluoridation began, much worthwhile information
was obtained and the effect of late commencement, if any, was to result
in underestimation of the fluoride protection.
Comment.
Dr Grainger does not state the nature of this "worthwhile
information" but, whatever it was, it could not compensate for the
lack of a pre-fluoridation caries assessment in this study. Its late
commencement could be justified only if it was known that the caries
rates in Brantford had not been affected by the ingestion of fluorides
prior to the baseline examination (p. 168). However, the results from the
City Health Department study, if taken at their face value, indicated
that there had been marked and erratic changes: at first a considerable
rise in the DMF rates after about one year of fluoridation, followed by a
marked fall during the second year. It is surprising, therefore, that,
out of all the cities in Canada, Brantford was chosen as the location of
two long-term studies, for it should have been obvious that the value of
the second study would be severely limited by the fact that the very
important data showing the pre-fluoridation caries rates could never be
obtained.
(31) Item 4: Reason for selection of
control cities. It seems clear that Brown (1951) gave adequate reasons
for selecting Sarnia and Brantford.
Comment.
As Dr Grainger notes, this paragraph refers to the selection of the
control cities, which were Sarnia and Stratford-not "Sarnia and
Brantford". The sole reference to the selection of control cities
which Brown (1951) gave is as follows: "The Ontario Dental Division,
under Dr Frank Kohli, volunteered assistance, as did Dr G. L. Anderson,
Medical Officer of Health for Sarnia, and Dr H. B. Kenner, Medical
Officer of Health for Stratford, and both these cities entered the study
as controls. (The water of Sarnia is fluorine-free, and that of Stratford
contains 1.3 ppm. of fluorine from a natural source.)" Dr Grainger
considers that "Brown (1951) gave adequate reasons" for the
selection of the control cities-but few would agree with him.
(32) Item 5: Re superior dental care in
Brantford. The difference in level of dental care between the cities is
factual as recorded by Brown (1952). This variation of numbers of teeth
classified as F. rather than D. or M. does not fundamentally influence
the DMF rate.
Comment.
Increased dental care usually includes some prophylactic treatments and,
as noted by Doctors Blayney and Hill (18). even regular examinations may
be accompanied by "more emphasis on the teaching of oral
health." This statement by Dr Grainger implies that he considers
that such increased dental care has no influence on the total DMF rate.
(33) Item 6: Comparability of rates. As
stated under Item 5, the dental condition of the children in Sarnia and
Brantford differed in 1948 because a lower level of dental treatment in
Sarnia resulted in higher tooth mortality. The tooth mortality rates thus
differed but it does not follow that the DMF rates differed.
Comment.
It does not state "that the DMF rates differed; it points out, as
its title states, the "Doubtful comparability of rates" owing
to the delay in setting up this study. Dr Grainger's comments suggest
either that he has not understood the meaning of the first sentence of
the paragraph, or that he is seeking to distract attention from the
presence of this important deficiency in the study-its late commencement.
(34) Brown's statement (1951) "by
1948 the Brantford data were not greatly different from those in
Sarnia" is obviously referring to DMF rates and hence quite valid.
Comment.
This quotation does not appear in Brown (1951) but a similar statement
was made by Brown et al. in
1953 and 1954 (b) and is given on page 169. The fact that it was
"obviously referring to DMF rates" was not questioned. The
implications of this remark were discussed.
(35) The differences in oral hygiene are
only remotely related to the DMF rates under discussion.
Comment.
Brown et al. (1954b) said that
"marked differences in oral hygiene as between the test and control
groups might conceivably affect the findings". Such "marked
differences" were reported-but were disregarded.
(36) Item 7: Concentration of fluorides.
The fluoride content of the Brantford water supply was raised to
approximately 1 ppm in June, 1945, and raised to 1.2 in February, 1949
Comment.
This statement of Dr Grainger is welcome because it provides the answer
to the question: Which of the statements regarding the concentrations of
fluorides in the Brantford water, which were reported on page forty-two,
are accurate and which ones are not?
(37) The Stratford water fluoride
content is believed to have been in the order of 1.3 to 1.6 ppm since
1917 when the wells were drilled. Naturally no analysis for fluoride was
available prior to the beginning of the interest in fluoridation and
early techniques for analysis were not as reliable as present methods.
Comment.
This statement is most revealing for it indicates that the wells at
Stratford have been analyzed to determine their fluoride content only
since "the beginning of the interest in fluoridation". If this
is the case, the statements of Brown et
al, (1953, 1956), concerning the "continuous" use of water
containing fluorides in concentrations of 1.3 ppm or 1.6 ppm since 1917
are not founded on data and are, therefore, merely different guesses.
(38) These facts have been recorded in
the writings of the primary workers (Hutton et al., 1951; and Brown et
al., 1951, 1952, 1953, 1954, 1956) and the differences in amounts
from other writers might seem less "strange" if they were
merely acknowledged to be minor misquotations.
Comment.
It was pointed out that the "facts" regarding fluoride
concentrations were stated differently in these papers. In regard to the
concentration in the Stratford supply, a comparison of the statements
made by Brown et al., in 1953
and 1956 suggests that the concentration of fluorides in this supply may
have increased from 1.3 to 1.6 in this three year period. The important
admission that the fluoride concentration in Stratford was obtained only
relatively recently, is not contained in any of the six "writings of
the primary workers" mentioned by Dr Grainger. Therefore his
statement is not correct.
As Dr Grainger suggests, it is not
unlikely that the statements regarding fluoride concentration of the
"other writers", the New Zealand Commission of Inquiry (1957)
and the Ontario Department of Health (1956), were "minor
misquotations".
(39) Item 8 Re statement by Brown et al (1956). The statement is
substantially correct with the exception that Brown's observational
period did not begin until 1948, hence is less than 10 years.
Comment.
Dr Grainger suggests that the phrase "more than ten years" is
incorrect. It was inserted into the quotation of a statement by Brown et al. (1956), but enclosed in
square brackets to indicate that it was not a part of the quotation. However,
in the sentence which immediately precedes that quotation Brown et al. (1956) said:
"Brantford has had more than 10 years of experience with 1 part per
million of fluoride in its water supply. During that time... "It is
clear that they were not referring to "Brown's observational
period" of about seven years, but to the period of fluoridation in
Brantford which commenced in June 1945 (Hutton et al., 1951; p. 173) and was, therefore, "more than 10
years".
(40) The decrease in mean df rates for
the 9-11 years group in Sarnia between the years 1948 and 1954 (Brown,
1954), did not continue into 1955.
Comment. The
1955 rate of 2.31 df was still below the 1948 and the 1951 figures of
2.50 and 2.41 respectively.
(41) There was a highly significant
decrease over the period 1948 to 1955 (2.37 to 1.93) in Brantford and no
significant decrease in Sarnia (2.50 to 2.31).
Comment. The
decrease mentioned by Dr Grainger (2.37 to 1.93) was reported in
Brantford between 1948 and 1954 (Brown et al., 1954b) not "over the period 1948 to 1955".
In 1955 this rate rose to 1.99 (Brown et
al., 1956), and the difference between 1948 and 1955 was no longer
said to be "highly significant" (Brown, 1955)
The rates quoted by Dr Grainger for
Brantford are for the years 1948 and 1954 (see 63). It should be noted
that it was between these two years that the maximum "decrease"
was reported in the rates in that test city (2.37 to 1.93). Furthermore,
in mentioning Sarnia, instead of giving the figures for the same period
(1948-54), 2.50 to 2.11, he cited the figures 2.50 to 2.31, which cover a
different period (1948-55) and do not reveal (Brown, 1955) the
significant "decrease", in the rate in this control city, which
was shown in the previous report (Brown et al., 1954b). By the use of these figures, the reviewer
exaggerates the contrast between the test city and this control. Thus,
this statement by Dr Grainger is both inaccurate and misleading.
(42) In the same periods the mean df
rates for this age [in] Stratford remained nearly equal (1.66 and 1.65)
and increased for other ages.
Comment.
The rates for the four examinations were: 1.66, 1.76, 1.58, 1.65 (Brown,
1955). (Throughout this monograph caries rates have been given in the
form in which they appear in the original papers although it is
recognized that, in cases such as these, the practice of showing caries
rates with two places of decimals is, probably, not warranted.) Dr
Grainger mentions the least variable of the ten caries rates in the
control cities-that for the deciduous teeth of children aged nine to
eleven years in Stratford. He omits to mention the DMF rates which show
the remarkable situation, in this control city, in which each of the
inter-year changes occurring in this age group, and in five out of the
six inter-year changes in the rates of the "other ages", were
said by Brown (1955) to be statistically significant.
(43) Item 9: Re Table 11, Ontario
Department of Health Report. The printing of dashes rather than
percentages for the control cities was to avoid confusing the table with
"negative reductions" and in the case of the 9 to 11 df figure
to avoid emphasizing what was considered to be a spurious decrease.
Comment.
This astonishing explanation, for the printing of dashes in this table,
implies that these omissions were made deliberately because the results
did not conform to those expected. Why should a decrease of 0.44 df (18
per cent) in the test city be accepted and published, but a very similar
one of 0.39 df (16 per cent) in a caries rate in the control city of Sarnia
be considered "spurious" and not published-a dash being shown
in the appropriate position in the table? By printing these dashes, the
"statisticians" of the Ontario Department of Health could have
misled their Minister into thinking that there were no changes in these
caries rates in Sarnia and Stratford (particularly as the Summary of the
report said so) but that there had been a decrease of eighteen per cent
in the corresponding rate in Brantford due to fluoridation.
Talk of "negative reductions"
cannot disguise the fact that nothing is more calculated to confuse a
table than (as Dr Grainger implies) the deliberate omission by
"statisticians" of figures giving the percentage changes in
rates (one of which was said to be significant).
(44) This judgement was borne out by the
1955 figures.
Comment.
Dr Grainger tries to justify this "judgment" by implying that
these so-called "spurious" decreases were not seen in the 1955
figures. However, small "decreases" were still shown in that
year, the "reduction" in Sarnia being 7.6 per cent.
In any case, this so-called
"judgment", regarding the omission of data, has no place in the
preparation of an unbiased report.
(45) Item 10: Differences in reported
rates between examiners. Different examiners give characteristically
higher or lower rates upon examining the same individuals due to
differences in skill, training the physical condition [sic]. Thus the
differences quoted are no reflection on the design of the experiment or
the care taken in the work. The strength of the double examinations comes
through corroboration of caries trends in Brantford over the years and
not through interchangeability of data.
Comment.
Dr Grainger refers to the differences between examiners in the assessment
of caries rates. This important matter has already been considered. The
aim of the paragraph mentioned was to show that, as the rates obtained by
the examiners in the two Brantford studies were different, data from the
City Health Department study could not be used to decrease "the
deficiency in the data of the National Health and Welfare study, owing to
its late commencement"
The admission, which is implicit in Dr
Grainger's remark, that "interchangeability of data" was not
permissible between the two studies in Brantford confirms the point made.
The degree of reliance which can be placed on the "corroboration of
caries trends in Brantford over the years" must be considered in the
light of the widely divergent results obtained in these studies, which
were discussed in the second paragraph of page three.
(46) Item 11: Significant fluctuations
in controls. The important point is that for the controls the inter-year
changes were upward trends or mere fluctuations (even though in some
cases calculated to be beyond change) [sic], whereas in Brantford the
change took the form of a highly significant continual downward trend.
Comment.
It was pointed out that in the control city of Stratford five out of the
six comparisons made between the permanent teeth rates of successive
years were said by Brown et al.
(1954b) to be significant changes (four of them being at the three
standard error level). In the permanent teeth rates in the other control
city, Sarnia, there were four highly significant and one significant
change in the nine comparisons made. Brown et al. (1953, 1954b) and Brown (1955) said that the odds
relating to the occurrence by chance or sampling variation of a
difference of the magnitude of three standard errors (such as were
reported in eight of these changes) "are 369 to I against". Therefore,
when Dr Grainger terms these unexplained changes "mere
fluctuations" he is rejecting that remark of Brown et al. and denying the meaning of
statistical significance.
Dr Grainger neglected to mention that
the "highly significant continual downward trend" in the caries
rates in Brantford occurred only in children who were aged twelve to
fourteen years. In the two other age groups, in both the deciduous and
the permanent dentitions, there was an upward trend in the caries rates
in the fluoridated city during the last year of the study, the rise from
0.44 DMF to 0.69 DMF, in the youngest age group, being said to be a
highly significant rise (Brown, 1955). Therefore this statement by Dr
Grainger, that there was a "continual downward trend" in Brantford,
is incorrect and is misleading.
(47) Item 12. Larger percentage changes
in control. There is no definite explanation as to why rates increased in
Stratford and also in Sarnia over the ten years but this may be a
reflection of a general post-war increase in dental caries which has been
seen in other areas. However, it is significant that in the various
fluoridation experiments e.g. in Brantford, Newburgh, Grand Rapids, etc.,
the shift has always been significantly downward in the fluoridated
cities whereas the control city rates have remained about the same or in
the case of Stratford, increased.
Comment.
Dr Grainger's statement, that the "rates increased in Stratford and
also in Sarnia over the ten years", is inaccurate for, as he pointed
out in his Item eight (39), "Brown's observational period did not
begin until 1948, hence is less than 10 years." Sarnia was first
examined in March 1948 and Stratford in October of that year (Brown,
1952). Therefore the caries rates of the children in both those towns
were known for a period of about seven years, not one of ten years.
Furthermore, in the deciduous teeth in Sarnia, the younger age group
showed a higher rate in 1955 than in 1948, but in the older children the
final rate was lower than the initial one. In this city the DMF rate rose
between 1948 and 1953 but between that year and 1955 there was a decrease
in this rate in each of the three age groups.
The suggestion that there has been
"a general post-war increase in dental caries" is not supported
by these studies, for such a rise it was not seen in any of the
unfluoridated control cities considered. In Muskegon and Oak Park there
was no definite trend. At the time when (as a result of their being
fluoridated) these cities ceased to serve as controls, the rates for the
children of some ages were higher, and for other ages they were lower,
than during the initial examination. The trend in Kingston cannot be
investigated owing to the method of presenting the data in the Newburgh
study. The contention that "the shift has always been significantly
downward in the fluoridated cities" can be accepted only if the many
deficiencies pointed out in this monograph are ignored and the figures
from these trials accepted at their face value.
(48) Item 13: Smaller percentage decrease
after longer fluoridation. As pointed out by Sutton himself on page 168
(middle paragraph) the fluoride protection for permanent teeth of the
children aged six to seven seemed to occur within two or three years
after fluoridation began. Thereafter the yearly DMF rates were subject to
random fluctuation and the differences in percentage decrease of 69 per
cent and 51 per cent are most likely a reflection of this inter-year
variation.
Comment.
No specific mention was made of "the children aged six to seven"
when pointing out the reductions in the DMF rates which were reported to
have occurred in the early years of the City Health Department study
(Hutton et al., 1951). Some
implications of this reported early decrease in caries rates were
discussed on pages two and thirty-eight.
When he makes the remark that "the
differences in percentage decrease of 69 per cent and 51 per cent are
most likely a reflection of this inter-year variation", Dr Grainger
shows that he could not have noted that the increase in the DMF rate in
these children, in the fluoridated city, from 0.44 in 1954 to 0.69 in
1955 (so that the "percentage decrease" dropped from 69 per
cent to 51 per cent), was shown by Brown (1955) to be, statistically
speaking, a highly significant (three standard error level) rise in the
rate in the test city during the final year of the study. Therefore, when
he makes this suggestion, he is expressing an opinion which contradicts
the notation given by Brown (1955), in his Table IV, which indicates that
the rise in rates which produced this percentage "decrease" is
statistically significant at the three standard error level.
Dr Grainger may be right-but if he is,
Brown's (1955) indication of statistical significance in this case is
incorrect, and the methods used in the National Health and Welfare study
for calculating statistical significance must be questioned. In
consequence, all statements made in the study regarding significant
changes in the caries rates, both in the test city and its controls,
become doubtful.
It is of interest to note that the
"1955 Report" from this study was released in two different
publications. The first, a booklet, was dated November 1955, and was
"prepared by H. K. Brown . . . with the assistance of H. R.
McLaren... G. H. Josie... and Barbara J. Stewart". The second
publication is a paper by Brown, McLaren, Josie and Stewart published in
1956 in the Canadian Journal of Public Health, no reference being made to
the previous publication. The ten tables and the two figures in the body
of these reports are the same and the text of both is practically
identical. However, there is one important difference: that part of the
discussion dealing with the unexplained rise (shown as significant) in
the DMF rate of children aged six to eight years in Brantford (and also
in the control city with the "optimum" concentration of
fluorides in its water), was omitted from the later report (Brown et al., 1956).
The questions should be asked: Why was this very important small section
of the original report omitted when it was published in the Journal? Why,
in both these 1955 reports, was the smaller percentage
"decrease" between the initial and the final caries rates of
the youngest age group in Brantford not published?
(49-50) Item 14 The quotation from the
Ontario Government Report is taken out of context from a series of
summary statements. The previous statement was to the effect that in
Brantford there had been a significant decrease of about 60 per cent in
DMF rates. In the statement following, as picked out by Sutton, it was
stated that "no change" occurred in Stratford and Sarnia(49).
It should be clear enough from the context at the words "no similar
downward change" were inferred(50)
Comment.
The charge that the quotation mentioned was "taken out of
context" is meaningless unless it implies that the sense of the
original statement has been altered. So that the reader can judge this
matter, the whole of paragraph three (the "previous statement"
referred to by Dr Grainger) and paragraph four are reproduced. The
quotation given on page 176, which was the one criticized, is shown here
in italic type to distinguish it from its context.
The evidence produced by the
investigators of the Brantford City Health Department and of the
Department of National Health and Welfare, independently show that since
the introduction of the fluorine in the water there has been a
significant decrease, amounting to approximately 60 per cent in the
number of decayed, missing and filled teeth suffered by Brantford school
children.
At the same time, it has been established that there has been no change in the
already low dental caries attack rates in Stratford which has 1.2 ppm of
natural fluoride in its domestic water, or in the relatively high rates
for Sarnia which has had virtually no fluoride in its water."
Dr Grainger suggests that the writers of
this report, when they used the expression "no change", really
meant "no similar downward change". However, as they were
members of the Division of Medical Statistics and, presumably, were
trained in the very precise science, of statistics, it is unlikely that
they would use such an inexact expression. Also, the term "downward
change" is a rather clumsy substitute for the word
"decrease" which was used in the previous paragraph (para. 3
above). Both these points suggest that Dr Grainger's interpretation is
incorrect.
(51) Item 15 Possible weighting effect.
The critic is referring to a possible shift in age distribution within
the group, e.g. a possible sampling shift within the six to eight-year
age group so that certain years had disproportionately higher or lower
numbers of eight-year-olds and hence higher or lower average caries
scores. This is rather remote in that selection methods used by Dr Brown
were the same each year; moreover very large shifts in age distribution
would be needed to produce the significant differences to which P N. R.
Sutton refers.
Comment.
After reading Dr Grainger's remarks it may be supposed that it was said
that the inter-year significant changes in caries rates, reported from
the control cities, were due to a "weighting" effect. However,
if the original paragraph is consulted, it will be found that it is
headed "Unexplained Significant changes in controls." A
"weighting" effect was mentioned as a possible explanation for
these unexplained changes. This suggestion was made following the failure
of the authors (Brown, 1951, 1952; Brown et al., 1953, 1954b, 1956) to advance even a suggestion why
these changes occurred. Dr Grainger's comment leaves these significant
changes in the caries rates of the control cities as the authors of this
study left them - unexplained.
This reviewer has made it clear that the
statements regarding the "continuous" use of water containing
fluorides in concentrations of 1.3 or 1.6 ppm since 1917 in Stratford are
not based on data (comment 37); and that the misleading omission of
figures from the Ontario Department of Health Report (1956) was made
deliberately (comment 43). However it has been seen that, although Dr
Grainger said (27) that his aim was "to help set the record as
straight as possible", most of his comments, if they had been
accepted at their face value, would have had the reverse effect.
MR J. FERRIS FULLER
Apart from the reviews already quoted
above, the only published criticism known to the author is that contained
in the Book Reviews section of the January 1960 issue of the New Zealand
Dental Journal. This was contributed by MR J. FERRIS FULLER, a member of
the Dental Research Committee of the New Zealand Medical Research Council
and a member of the Fluoridation Committee of the Department of Health,
whose submissions to the New Zealand Commission of Inquiry (1957) are
mentioned in over twenty paragraphs of its report.
Mr Fuller's review stated:
"Everyone is out of step except our
Albert," or so the author would have us conclude. Altogether an
extraordinary book; clever but unfortunate; skilfully contrived and
yet-stripped of its finery-rather slender. It could be ignored if the
matter rested within the Sciences; but since by the very nature of the
subject it takes us into the public forum, some of the errors must be
stated..
Part I of Fluoridation: Errors and
Omissions in Experimental Trials (Chapter 19 here) is a reprint of a
paper by Sutton and Amies (see footnote on page 136) that appeared
recently in the Medical Journal of Australia criticising the
Brantford-Sarnia-Stratford study in Canada(52). But the authors have
omitted to read the literature(53), and their criticisms therefore are
not based on the known facts. This is a serious matter especially when
the comments come from two critics who exalt themselves above fellow
scientists of at least equivalent status in other parts of the world.
They accuse the Canadian workers of failing to devise a randomisation
procedure that would eliminate bias(54), of deliberately omitting vital
information in some of the tables(55), and finally of displaying bias in
the presentation of results(56). Their comments are based on a report of
the Ontario Department of Health (1956) to the Ontario Minister of
Health, a report obviously written in simple abbreviated terms for public
consumption(57). Sutton and Amies failed to read two official
publications readily available(58), namely, a 51-page booklet "A
suggested methodology for fluoridation surveys in Canada" and the
35-page detailed report of the Department of Health and Welfare, of
November, 1955 These two booklets together show that great care was taken
to introduce a well-designed randomisation procedure(59), that examiner
variability was eliminated as far as humanly possible by the employment
of one examiner only throughout the whole period of the study(60), and
that the information alleged to have been omitted is in fact shown in
detail in the tables in the 1955 report(61), together with the standard
error for each of the indices used. In short, the more important
criticisms that appear so damaging are in fact without foundation. Thus,
when the authors say that "what must be eventually a statistical
study does not appear to have been designed as such" and "no
attempt at statistical evaluation has been considered" their
comments are absurd and, indeed, irresponsible(62). The full official
report on the Brantford study was available in New Zealand, incidentally,
when the Commission of Inquiry held its hearings(63), and three of its
tables are included in the published report of the Commission.
In Part 2 of the book Sutton continues
in the same vein. He complains that misleading comments are made in some
reports, yet his own book contains many misleading statements. For
example, he claims that a proper evaluation of examination errors at
Grand Rapids has not been carried out(64), and he doubts the accuracy of
caries attack rates in test and control areas because X-ray examinations
were incomplete or absent(65). It is significant that he omits to refer
to a report by Hayes, McAuley, and Arnold published in the U.S. Public
Health Report in December, 1956, which is a key reference in this
subject(66). This report met the specific point that "some observers
have suggested that X-rays are essential to determine the efficacy of
caries control measures" and an investigation was undertaken
"to determine whether or not supplementing direct observation with
X-ray examinations would affect the conclusions based on direct
observation alone." The conclusion was that supplementary X-ray
examinations supported the clinical findings and did not change the basic
observation that substantial decreases in dental caries occurred during
the test period. The very standard errors that Sutton demands for a
proper statistical evaluation were available in this report(67). He
quotes a subsequent (1957) paper by McAuley that suits his book and, in
the light of his criticisms and allegations, this makes the omission of any
reference to the 1956 report more damaging(68). To borrow his own phrase,
omissions of this nature render his work "open to doubt."
Sutton criticises his overseas colleagues for their inability to examine
children in control towns prior to fluoridation(69). With personal
experience of a study of this nature he would appreciate that where on
the one hand the interests of a large number of people and their local
bodies and institutions are concerned as compared with only one or two
examining personnel on the other, it is almost impossible to operate a
plan to the exactitude dreamed of at the statistician's desk. In any
event, the criticism is rather meaningless as far as the Grand Rapids
study(70) is concerned when we realise that the baseline examination in
the control city of Muskegon showed that caries prevalence in that city
is of the same order as in Grand Rapids.
In attacking the Evanston-Oak Park
study, Sutton bemoans the lack of information about the design of the
study and phrases such as "It is not clear...", "It is not
understood...", (It) was not stated..." give the lead to
questions and speculations that follow. But why not adopt the simple
expedient of writing to the workers concerned and so finding out instead
of speculating? This attitude is typical of the book(71). And typical
also is the quibbling over details that do not detract one iota from the
part that fluoridation has played in these areas in reducing dental
decay(72). "The total tooth surfaces considered... should be 58,325,
not 58,352" says the author, and also... the mean of these values
for 1946... is 150.09, not 149.76"(73). Dear me, Dr Sutton, how
dreadful.
And then we come to the
Newburgh-Kingston study. Prominence is given to the different composition
of the waters at Newburgh as compared with the control city of
Kingston(74), and this is cited as the reason why the latter is
unacceptable as a control. But once again Sutton omits any reference to a
key report, that by Dean, Arnold, and Elvove of August, 1942, listing
caries prevalence rates in communities where the variables in the
domestic water mentioned by Sutton varied to a greater degree than
between Newburgh and Kingston without caries prevalence being markedly
affected(75).
The author complains of bias in the
manner in which some results are presented but, as can be seen, he
displays bias himself in the choice of articles he quotes(76) and in his
omission to read others. It is not surprising, therefore, to see him fall
into the familiar pattern of the anti-fluoridationist. Those who question
fluoridation are given the familiar title of "eminent
authorities," a distinction not afforded anyone else(77). It is
surprising, however, to see him serve his ends by quoting Feltman's study
on the use of fluoride tablets. This study lacks the very control that
one would expect Sutton to consider essential(78).
As one would expect, there are no
bouquets for the New Zealand Commission of Inquiry, one complaint being
that "no mention was made of the employment of a statistician to
assist its members in evaluating numerical data." Had the author
inquired, he would have been told that the Professor of Biochemistry on
the Commission was well versed in biometrics, and that scientific
witnesses quickly discovered that tables were unacceptable unless they
contained complete details including standard errors, so that he could
evaluate data statistically for himself and the Commission(79).
Finally, a warning to those reading this
book, lest they be misled by the polemics and the array of figures. Please
note that Sutton's conclusions in part 2 (which forms the greater part of
the book) are confined to variations in the prevalence of dental decay in
control cities and not to the cities where fluoride has been added(80).
What of the places where fluoridation has been adopted? Sutton does not
dispute the fact that the prevalence of dental decay has been
substantially reduced in the fluoridation cities of Grand Rapids,
Newburgh, Brantford, and Evanston(81), nor does he mention that these
good results have been confirmed by several independent studies in the
U.S.A., and also in Tasmania, Brazil, Japan, Germany, Sweden, and at
Hastings in New Zealand(82). The validity of the results from Hastings,
incidentally, has been checked by the Applied Mathematics Laboratory of
the New Zealand Department of Scientific and Industrial Research(83).
The anti-fluoridationists will rejoice
with fresh ammunition to replenish their stocks; but it is unlikely that
this work will serve any useful purpose in scientific circles despite the
author's rather pretentious hopes. The performance is almost as old as
Time: "The mountains are in labour, there will be born a ridiculous
mouse," said the ancient poet.
Cover
| Introduction
| 1a | 1b | 1c | 1d | 2a | 2b | 2c | 2d | 3
|
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