Change of urinary fluoride and bone metabolism indicators in the endemic fluorosis areas of southern china after supplying low fluoride public water

Abstract

BackgroundFew studies have evaluated health impacts, especially biomarker changes, following implementation of a new environmental policy. This study examined changes in water fluoride, urinary fluoride (UF), and bone metabolism indicators in children after supplying low fluoride public water in endemic fluorosis areas of Southern China. We also assessed the relationship between UF and serum osteocalcin (BGP), calcitonin (CT), alkaline phosphatase (ALP), and bone mineral density to identify the most sensitive bone metabolism indicators related to fluoride exposure.MethodsFour fluorosis-endemic villages (intervention villages) in Guangdong, China were randomly selected to receive low-fluoride water. One non-endemic fluorosis village with similar socio-economic status, living conditions, and health care access, was selected as the control group. 120 children aged 6-12 years old were randomly chosen from local schools in each village for the study. Water and urinary fluoride content as well as serum BGP, CT, ALP and bone mineral density were measured by the standard methods and compared between the children residing in the intervention villages and the control village. Benchmark dose (BMD) and benchmark dose lower limit (BMDL) were calculated for each bone damage indicator.ResultsOur study found that after water source change, fluoride concentrations in drinking water in all intervention villages (A-D) were significantly reduced to 0.11 mg/l, similar to that in the control village (E). Except for Village A where water change has only been taken place for 6 years, urinary fluoride concentrations in children of the intervention villages were lower or comparable to those in the control village after 10 years of supplying new public water. The values of almost all bone indicators in children living in Villages B-D and ALP in Village A were either lower or similar to those in the control village after the intervention. CT and BGP are sensitive bone metabolism indicators related to UF. While assessing the temporal trend of different abnormal bone indicators after the intervention, bone mineral density showed the most stable and the lowest abnormal rates over time.ConclusionsOur results suggest that supplying low fluoride public water in Southern China is successful as measured by the reduction of fluoride in water and urine, and changes in various bone indicators to normal levels. A comparison of four bone indicators showed CT and BGP to be the most sensitive indicators.

Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation

“…Our data also indicates that tea consumption by infants will result in excessive intake of fluoride which is associated with a high risk of dental fluorosis. Recently, Chen et al provided a biological dose-exposure response relationship for fluoride exposure and bone metabolism indicators and demonstrated that when urinary fluoride levels increased above 0.3 mg/L, the percentage of children with abnormal bone metabolism increased significantly [ 127 ]. Székely et al examined urinary fluoride excretion after tea consumption in young adults residing in a community with a fluoride level in drinking water of 0.1 mg/L and determined that the consumption of 200 mL of tea per day with a fluoride content of 0.42 mg increased 24 h urinary fluoride levels from 0.297 mg/L to 0.451 mg/L [ 128 ].…”

Aberrant methylation‐induced dysfunction of p16 is associated with osteoblast activation caused by fluoride

“…ALP and BGP have been recognized as early and important indicators in the evaluation of bone formation . Therefore, ALP activity and BGP content in the human osteoblasts were determined.…”

Fluoride Exposure Induces Inhibition of Sodium/Iodide Symporter (NIS) Contributing to Impaired Iodine Absorption and Iodine Deficiency: Molecular Mechanisms of Inhibition and Implications for Public Health

“…[151]. A large body of evidence from epidemiological studies has demonstrated that F is a potent inducer of CT expression in humans [152,153,154,155,156,157]. Of fundamental importance is the research by Chen and associates in providing a biological dose-exposure response relationship for F exposure on CT expression at relatively low intakes.…”

“…Of fundamental importance is the research by Chen and associates in providing a biological dose-exposure response relationship for F exposure on CT expression at relatively low intakes. Notably, in this study, it was demonstrated that differential expression of CT occurs when urinary F levels exceeded 0.38 mg/L [155].…”