Objective: To investigate the effect of different concentrations of fluoride and iodine in drinking water on children’s dental fluorosis and thyroid function.
Methods: According to different concentration of fluoride and iodine in drinking water, four villages in two counties of Henan province were classified as high fluoride and iodine, high fluoride, high iodine, and control area. Children who were born and grew in the four areas were chosen for dental fluorosis examination with Dean’s method. The prevalence rate of the goiter, and the concentrations of FT3, FT4 and TSH in serum were detected with radio-immunoassay method among the children.
Results: The prevalence of goiter in children from high fluoride and iodine, high fluoride, high iodine and control areas were 19.2%, 12.7%, 19.4%, and 8.3%, respectively. There was no significant difference in goiter prevalence among the four groups ( P > 01 05). The prevalences of dental fluorosis were 49.4% and 46.5% in the children living in the high fluoride and iodine area and high fluoride area, rsepectively. No dental fluorosis case was found in high iodine and control area. There was no signif icant difference in the concentration of serum FT3 among the children from the four areas (P < 0105). The content ratios of serum FT4 and TSH in ch ildren from high fluoride and iod ine area were higher than that of in the children from the other three areas (P < 0105). There were no significant difference in serum FT4 betw een the ch ildren from high fluoride area, high iodine area and control area (P > 0105). The concentration of serum TSH of children from high fluoride and iodine area and high iodine area was higher than that of children from high fluoride area and control area.
Conclusion: High fluoride and iodine increase the prevalence of goiter. High iodine increases the concentration of FT4. Fluoride can increase the concentration of FT4 under high iodine condition.