TABLE 10-1 Summary of Recent Genotoxicity Studies of Fluoride

Population or System/Method and Assay

Findings

Remarks

References

In vivo human studies

Subjects (n = 746) with normal or inadequate nutrition living in regions of China with water concentrations of fluoride at 0.2, 1.0, or 4.8 mg/L.

Assay: SCE in blood lymphocytes.

Subjects in the 4.8-mg/L region had lower average SCEs per cell.

Plasma and urine fluoride concentrations also measured; these were proportional to water concentrations.

Y. Li et al. 1995

Comparison of 100 residents of North Gujarat exposed to drinking water with fluoride at 1.95 to 2.2 mg/L with 21 subjects in Ahmedabad exposed at 0.6 to 1.0 mg/L.

Assay: SCE in blood lymphocytes and cell cycle proliferative index.

SCE rate was significantly greater in subjects from North Gujarat, but there was no difference in the cell cycle proliferative index.

Insufficient documentation of subject ascertainment or control for potential demographic confounding.

Sheth et al. 1994

Phosphate fertilizer workers with inhalation exposure.

Assay: chromosome aberrations, micronucleus, SCE.

Exposed workers had elevation in all cytogenetic outcomes tested.

 

Meng et al. 1995; Meng and Zhang 1997

Peripheral blood lymphocytes from inhabitants of the Hohhot region in inner Mongolia (n = 53 with fluorosis; n = 20 with no fluorosis) exposed to fluoride in drinking water at 4 to 15 mg/L compared with controls (n = 30) exposed to fluoride at < 1 mg/L.

Assay: SCE and micronucleus.

SCE: higher frequency in individuals with fluorosis (87% increase in SCEs), than no fluorosis (13% increase) compared with controls.

Micronucleus: higher frequency in individuals with fluorosis (3.4-fold increase) than no fluorosis (1.8-fold increase) compared with controls.

Insufficient documentation of subject ascertainment or control for potential demographic confounding.

Wu and Wu 1995



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