Journal of Dental Research, Vol 74, 1468-1474, Copyright © 1995 by International & American Associations for Dental Research Online Journals
Long-term exposure to fluoride in drinking water and sister chromatid exchange frequency in human blood lymphocytes
Y. Li, C. K. Liang, B. P. Katz, E. J. Brizendine and G. K. Stookey
Indiana University School of Dentistry, Indianapolis 46202, USA.
The genetic toxicity of fluoride has been investigated extensively by
various test systems. However, results obtained have been inconsistent.
Fluoride has been reported to be non-genotoxic, genotoxic, and synergistic
or antagonistic with certain mutagens. To date, there are no published
human studies on the genotoxicity of fluoride. The purpose of this
investigation was to determine genotoxic risks of long-term exposure to
various concentrations of fluoride in drinking water in humans with normal
or inadequate nutrition. Six groups of subjects with either normal or
inadequate nutritional intakes were selected from areas of approximately
0.2, 1.0, or 4.8 ppm (10.5, 52.6, or 252.6 mumol/L) fluoride in water. The
subjects had been continuous residents in the area for at least 35 years.
Samples of drinking water, plasma, and urine were analyzed for fluoride
content. Blood lymphocytes were examined to determine the frequency of
sister chromatid exchange (SCE). Blood chemistry and electrolytes were also
analyzed. The results showed that average daily fluoride intake as well as
urine and plasma fluoride levels increased with increase in the fluoride
content of the drinking water. The blood chemistry and electrolyte values
were within the normal range for all populations, but several parameters
were significantly different. While the numerical differences were small,
the subjects with low fluoride in the water (0.11 and 0.23 ppm or 5.8 and
12.1 mumol/L) had significantly higher SCE frequencies than those with
higher fluoride exposures.(ABSTRACT TRUNCATED AT 250 WORDS)
