RÉSUMÉ
Objective To evaluate the control effect of the policy sustainable elimination of iodine deficiency disorders on the disease status after 15 years salt iodization, and to provide a scientific basis for the relevant policy adjustments. Methods Probability sampling method (PPS) was used to select 30 counties in Jiangsu province(except those iodine excess areas), of each county 40 children aged 8 - 10 were selected as the investigation objects, their thyroids were examined by palpation and B ultrasound, urinary iodine(UI), household salt iodine, and intelligence quotient(IQ) were also investigated. A questionnaire-based health education survey of children and women was also conducted. Results A total of 1200 salt samples were detected and the coverage and qualified rates of iodized salt were 97.5%(1170/1200) and 94.5%(1134/1200), respectively. Five hundred and ninety eight urinary samples of children aged 8 to 10 were detected. The median urinary iodine was 325.3 μg/L. Of 1200 children aged 8 to 10 examined, goiter was 1.70% (20/1200) by palpation and 1.00% (12/1200) by B ultrasound. Average IQ of those 598 children was 112.4 ± 13.2, and the proportion of mental retardation was 0.5% (3/598). The health education awareness were 95.9%(1830/1908) and 96.4%(431/447) for 636 students and 149 family women, respectively. Conclusions The control effect of iodine deficiency disorders is significant in Jiangsu province. Salt iodine concentration should be adapted to people's iodine nutritional status. Iodine nutrition needs of special population such as pregnant, lactation women and infants should be taking into account, and should also be combined with salt iodization status surveillance at county level.
RÉSUMÉ
Objective To investigate the daily total fluoride intake in relating to the prevalence of skeletal fluorosis in two villages in Jiangsu Province,in order to provide the scientific evidences for the control and prevention of endemic fluorosis.Methods Adults sampled from a high-fluoride Village,Wamiao,and a low-fluoride Village,Xinhuai,were surveyed in this study according to the fluoride concentration in their household shallow well.The average daily total fluoride intake from difierent sources and the skeletal fluorosis were investigated in each subject.Then the subjects from two villages were allocated into five subgroups(＜2.00,2.00～,3.00～,4.00～,≥5.00 mg/d),the relation fluoride intake and prevalence of osteofluorosis was analyzed.Results The prevalence of skeletal fluorosis in Wamiao Village was 31.06%(41/132),but no skeletal fluorosis case(0/35)was found in Xinhuai Village.According to the daily total fluoride intake,subjects with higher daily total fluoride intake tended to associated with a higher prevalence of skeletal fluorosis in a significant dose-response relationship(regression equation:y=2.624-6.855x+3.424x2:r=0.997).The benchmark dose lower limitation of daily total fluoride intake with 95% confidencewas 2.50 mg/d calculated according to this dose-response relationship,the reference dose(RfD)was 2.50 mg/d.In Wamiao Village a significant difference was also found between daily total fluoride intake in 41 subjects[(5.09±1.20)mg/d]with X-ray detectable skeletal fluorosis and in 91 subjects[(3.08±1.12)mg/d]without X-ray detectable skeletal fluorosis(t=-9.32,P＜0.01).Conclusions These findings indicate that the daily total fluoride intake has a significant dose-response relationship with the prevalence of skeletal fluorosis in an endemic fluorosis area associated with high-fluoride drinking water;and the RfD in this study was lower than that in the national standard of"Chinese hygienic standard for daily total fluoride intake(WS/T 87-1996)"(3.50 mg/d).
RÉSUMÉ
<p><b>OBJECTIVE</b>By using Benchmark Dose (BMD) approach to explore the relations among drinking water fluoride, urine fluoride, serum fluoride and dental fluorosis; and to evaluate the significance of urine fluoride and serum fluoride in control and prevention of endemic fluorosis.</p><p><b>METHODS</b>512 children (290 in Xinhuai Village, 222 in Wamiao Village) aged 8-13 years were recruited in the study. Epidemiological methods were used to investigate the prevalence of dental fluorosis, and the levels of urine fluoride, serum fluoride, and drinking water fluoride in superficial well. The children were divided into six subgroups by the concentration of fluoride in drinking water: < 0.5 mg/L, 0.5-mg/L, 1.0-mg/L, 2.0-mg/L, 3.0-mg/L and > or = 4.0 mg/L.</p><p><b>RESULTS</b>There was significant dose-response relationship between the drinking water fluoride and the prevalence of dental fluorosis or the prevalence of defect dental fluorosis. The BMDLs (Benchmark Dose Lower Bound) were 1.01 and 1.30 mg/L, respectively. Urine fluoride and serum fluoride also had significant dose-response relationship to the prevalence of dental fluorosis or defect dental fluorosis. The correlation coefficient between drinking water fluoride and urine fluoride was 0.717, and it was 0.855 between drinking water fluoride and serum fluoride, and 0.617 between urine fluoride and serum fluoride.</p><p><b>CONCLUSIONS</b>The currently national standard of fluoride in drinking water in China is safe and reasonable. As a biological monitoring index, the levels of fluoride in serum may be more useful than that in urine in the control and prevention of endemic fluorosis.</p>