Objective To observe the change of bone resorption markers, serum N-telopeptide of type Ⅰ collagen (NTx) and serum tartrate resistant acid phosphatase-5b (TRACP-5b), among residents in coal-burning endemic fluorosis areas.
Methods Doujing Village, Liupanshui City, Guizhou Province, was elected as the fluorosis area where high-fluoride coal was used as common home fuel, and the control area was Huaga Village where woods were often used. Dental fluorosis, urinary fluoride, serum NTx, and serum TRACP-5b were detected in 102 residents in the fluorosis area and 45 residents in the control area, and dental fluorosis index was calculated.
Results The detection rate of dental fluorosis of residents in the fluorosis area was 79.4%, higher than that in the control area (8.8%) (χ2=69.669, P < 0.001); the urinary fluoride level of residents in the fluorosis area was 1.59 (1.22-2.50) mg/L, also higher than that in the control area 0.65 (0.42-1.04) mg/L (Z=-6.024, P < 0.001). The dental fluorosis index of residents in the fluorosis area was 2.24, indicating a prevalent dental fluorosis condition; the index in the control area was 0.23, indicating a negative condition. The average concentration of serum NTx in the fluorosis area 12.34 (10.93-13.96) nmol/L was higher than that in the control area 9.21 (7.86-12.91) nmol/L (Z=4.062, P=0.000), and the average concentration of serum TRACP-5b in the fluorosis area 207.87 (187.23-251.52) ng/L was lower than that in the control area 237.36 (207.47-305.95) ng/L (Z=2.938, P=0.003). The average concentrations of serum NTx of the 18-years age group and the 60-years age group in the fluorosis area were higher than that in the control area (Ps < 0.001); the average concentration of serum TRACP-5b of the 45-years age group in the fluorosis area 209.86 (187.40-276.05) ng/L was lower than that in the control area 254.07 (226.81-305.07) ng/L (Z=2.268, P=0.023). For the residents in the fluorosis area, serum NTx was positively correlated with serum TRACP-5b (r=0.544, P=0.001), and dental fluorosis degree was positively correlated with age (r=0.242, P=0.014). No association was found of either serum levels of NTx or TRACP-5b with dental fluorosis degree (r=0.065, P=0.516; r=0.009, P=0.932) or age (r=0.010, P=0.918; r=-0.043, P=0.670).
Conclusion Over-intake of fluorosis may cause increased serum NTx and decreased serum TRACP-5b in adults, and serum NTx is associated with serum TRACP-5b. But the associations between the two indicators and fluorosis need further verification.
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