"(The likelihood of fluoride acting as a genetic cause
of cancer requires consideration.)" see last
sentence.
Regression analysis of cancer incidence rates and water
fluoride in the U.S.A. based on IACR/IARC (WHO) data (1978-1992).
International Agency for Research on Cancer.
Takahashi K, Akiniwa K, Narita K.
Department of Physical Medicine, Faculty of Medicine, University of Tokyo,
Japan.
Age-specific and age-standardized rates (ASR) of registered cancers for nine
communities in the U.S.A. (21.8 million inhabitants, mainly white) were
obtained from IARC data (1978-82, 1983-87, 1988-92).
The percentage of people supplied with "optimally" fluoridated
drinking water (FD) obtained from the Fluoridation Census 1985, U.S.A. were
used for regression analysis of incidence rates of cancers at thirty six
sites (ICD-WHO, 1957).
About two-thirds of sites of the body (ICD) were associated positively with
FD, but negative associations were noted for lip cancer, melanoma of the
skin, and cancers of the prostate and thyroid gland.
In digestive organs the stomach showed only limited and small intestine no
significant link.
However, cancers of the oral cavity and pharynx, colon and
rectum, hepato-biliary and urinary organs were positively associated with
FD.
This was also the case for bone cancers in male, in line with results of
rat experiments. Brain tumors and T-cell system Hodgkin's disease,
Non-Hodgkin lymphoma, multiple myeloma, melanoma of the skin and monocytic
leukaemia were also correlated with FD.
Of the 36 sites, 23 were positively significant (63.9%),
9 not significant (25.0%) and 4 negatively significant (11.1%).
This may indicate a complexity of mechanisms of action of fluoride in the
body, especially in view of the coexising positive and negative correlations
with the fluoridation index.
The likelihood of fluoride acting as a genetic cause of
cancer requires consideration.