Various variables in FNB and FSB areas
| FNB areas | FSB areas | p Values | |
|---|---|---|---|
| Dental fluorosis | |||
| Data collected/investigated villages (n/N)* | 1318/1404 | 558/581 | |
| Subjects (children) | 54855 | 26931 | |
| Age (years) | 10.07±1.44 | 10.08±1.44 | 0.32 |
| Female sex (N/%) | 25395(46.52) | 12610(46.82) | 0.42 |
| Prevalence rate of dental fluorosis (N/%) | 27669(50.44) | 5121(19.02) | <0.001 |
| Dental fluorosis index† | 1.09 | 0.40 | |
| Fluoride content in urine (mg/l)‡ | 2.31(1.41, 3.82) | 0.90(0.54, 1.51) | <0.001 |
| Fluoride content in water (mg/l)‡ | 2.17(1.66, 2.94) | 0.54(0.29, 0.77) | <0.001 |
| Skeletal fluorosis | |||
| Data collected/suvey villages (n/N)* | 1152/1404 | 470/581 | |
| Subjects (adults) | 406298 | 188400 | |
| Age (years) | 42.36±16.79 | 42.91±16.67 | <0.001 |
| Female sex (N/%) | 196526(48.37) | 92711(49.21) | <0.001 |
| Prevalence rate of clinical skeletal fluorosis (N/%) | 43940(10.81) | 9082(4.82) | <0.001 |
| Fluoride content in urine (mg/l)‡ | 2.38(1.50, 4.07) | 1.05(0.69, 1.75) | <0.001 |
| Fluoride content in water (mg/l)‡ | 2.17(1.62, 3.05) | 0.53(0.35, 0.75) | <0.001 |
FSB and FNB areas: fluoride-safe water supply project had been built and not been built in these areas.
*Only have dental fluorosis or clinical skeletal fluorosis in some villages; values are mean±SD for continuous variables.
†The variable was calculated as (questionable number×0.5+very mild number×1+mild number×2+moderate number×3+severe number×4)/the total number of subjects.
‡Log transformed before analysis, and data were expressed as M-estimator by Andrew and IQR (P25–P75).