Objective: To investigate the control effect of water improvement for endemic fluorosis over a long period of time, the health status of the residents in the disease area and the restoration to health of endemic fluorosis patients.
Methods: It was investigated that the water improvement lasting for 40 years and the rate of the dental fluorosis and fluorosis in Erzijing Village of Qian’an County, Jilan Province, where endemic fluorosis seriously prevailed. The rate of dental fluorosis of children aged 8-12 years and adults were examined with Dean’s index. The fluoride content in urine of the children and adults were determined with FSIE methods. A number of the residents took radiography in pelvis, forearm, and shank. The content of calcium (Ca), phosphonium (P), alkaline phosphatase (ALP), urea nitrogen (BUN), and total protein (TP) in serum was determined respectively.
Results: The rate of dental fluorosis was 22.2% and 45.2%, and the fluoride content in urine was 1.51 and 0.89 mg/L respectively in children aged 8-12 years and adults 16 and up. The positive rate of symptoms of fluorosis and of impaired function of bone and joints was 29.3% (57.7% before water improvement) and 14.6% respectively in adults. The skeletal fluorosis was revealed by radiography and the content of serum Ca and TP was lowered in a number of the residents.
Conclusions: It was an effective method by drinking defluoridated water for controlling endemic fluorosis, that is to stop taking in excessive fluoride and to promote excretion of fluoride. Patients with dental fluorosis and skeletal fluorosis are very difficult to thoroughly restore to health even though they have terminated intake of excess fluoride over a long period of time.