Studies on Fluoride-aluminum Combined Toxicosis

ed from papers presented at the XXth Conference of the International Society for Fluoride Research, Beijing, China, September 5-9, 1994, and published in the Journal of Guiyang Medical College. 1. Environmental Sanitation and Epidemiology In the Shuicheng area of Guizhou Province more than 1500 people were examined and screened for F-Al combined toxicosis. Blood and urine from patients and normal youths in the endemic area were collected and assayed for F and Al. X-ray pictures of the two groups were taken and analyzed, and an investigation of the environment was also conducted. The results revealed that the patients belonged to families in which corn dried by burning coal mixed with kaolin was eaten. Among the people examined, 50 had osteomalacia, corresponding to an incidence of 3.95%. For the youths who were less than 20 years old, the morbidity was 6.13%. The Al and F contents in the blood and urine of the patients were significantly higher than those of the control group. Al levels in blood and urine of sick children were significantly higher than those of normal children in the toxicosis area where the grain dried by burning the coal mixture absorbed large amounts of aluminum. Biochemical tests on 84 patients and 47 normal people disclosed that the levels of lactic dehydrogenase (LDH) and creatine phosphate kinase (CPK) activities as well as the contents of Cu and P were increased (p < 0.001), but the alkaline phosphatase (ALP) level decreased. The level of lipoxygenase (LPO) and antioxidation were measured on 12 sick children and 21 normal children in the toxicosis area as well as on 11 normal children in the control area. Glutathione peroxidase (GSH-Px) activity in the plasma of children in the toxicosis area was decreased. There were no significant differences between the toxicosis and control groups for plasma superoxide dismutase (SOD) activity, LPO content, GSH level, and red blood cell count (RBC). The intelligence of 196 children (6.5-12 years old) was measured by a drawing test. It was found that the mean intelligence score of children in the toxicosis area was clearly lower than that of children in the control area. F and Al levels in blood and urine from 100 osteomalacia patients in endemic areas of Guizhou and Hebei were also determined and were found to be significantly higher than in those of controls. Thus F-Al combined toxicosis is endemic in the severe fluorosis areas. 38 Conference Abstract Fluoride 28 (1) X-rays of 150 persons in the endemic areas were taken. The prevalence of abnormal radiology was 65%. Elemental analysis of blood and urine from 68 youths in the endemic area revealed changes of Zn, Mo, Mn, and Fe levels were related to the levels of Ca, P, Mg, and Cu. For example, there was a negative relationship between Zn and Mo in the patient group, but a positive relationship between Zn and Mo in the control group. 2. Animal Toxicology In experiments with male chickens, F and Al contents in the biomaterial were determined, and structural changes in the bones were assayed by a histomorphometric method with tetracycline as a tissue marker. A synergism was found between F and Al when the ratio of F and Al in diet was 2:1, but independent action was found when the ratio was 1:1. In experiments with rabbits, Al-F combined toxicosis was related to the chemical forms of aluminum as well as F and could accelerate accumulation in bone. The accumulation of Al in bone from organic Al in food was accelerated by F in the diet, but inorganic Al in the diet had an antagonistic effect against F. In experiments with rats, it was confirmed that F can increase Al absorption and accumulation. It was also found that dental fluorosis and damage to kidney function were related to F-Al combined toxicosis. These results indicated that Al has a contributing relationship to fluorosis. Based on the foregoing experiments, therapeutic experiments with Al-F intoxicated rats were carried out. Boron and silicon reduced blood F levels in the control and Al groups. Boron, silicon, and zeolite significantly decreased bone Al, which therefore might have therapeutic value. 3. Clinical treatment and prevention To cut off sources of F and Al intake, it is necessary for people not to do direct drying of food or grain by burning coal or coal mixed with kaolin. In order to set up models, the stoves of 70 families were improved with proper ventilation. Operations were also performed on three patients with osteomalacia. In the clinical work, health education was provided in many ways. A comprehensive plan for prevention and treatment based on decreasing total F and Al intake was prepared and submitted to the Government for approval.