Table 1.
Characteristics of fluorosis cases and controls.
| Variables |
Case (n = 200) |
Control (n = 200) |
P-value |
|---|---|---|---|
| Age, years (Mean ± SD) | 49.8 ± 13.4 | 49.7 ± 13.5 | 0.916 |
| Body mass index, kg/m2 (Mean ± SD) | 23.8 ± 3.9 | 23.6 ± 3.9 | 0.253 |
| Urine fluoride, mg/L (Mean ± SD) | 1.62 ± 1.0 | 1.28 ± 0.6 | <0.001 |
| Duration of residence, years (Mean ± SD) |
39.7 ± 18.1 | 39.717.1 | 0.951 |
| Dental fluorosis | 193 | 193 | |
| Skeletal fluorosis | 87 | 87 | |
| Female (%) | 115 (57.5) | 115 (57.5) | 0.923 |
| Ethnic (%) | 0.313 | ||
| Han | 118 (59.0) | 108 (54.0) | |
| Others | 82 (41.0) | 92 (46.0) | |
| Marital status (%) | 0.584 | ||
| Married or cohabitation | 172 (86.0) | 168 (84.0) | |
| Divorce or widowed | 18 (9.0) | 17 (8.5) | |
| Unmarried | 10 (5.0) | 15 (7.5) | |
| Education level, years (%) | 0.008 | ||
| ≤6 | 162 (81.0) | 141 (70.5) | |
| 6–9 | 32 (16.0) | 39 (19.5) | |
| ≥10 | 6 (3.0) | 20 (10.0) | |
| Household income, Yuan/month (%) | 0.049 | ||
| <500 | 23 (11.5) | 11 (5.5) | |
| 500–2,000 | 55 (27.5) | 64 (32.0) | |
| 2,000–6,000 | 94 (47.0) | 86 (43.0) | |
| ≥6,000 | 28 (14.0) | 39 (19.5) | |
| Fuel type (%) | 0.053 | ||
| Raw coal | 116 (58.0) | 127 (63.5) | |
| Mixed coal | 44 (22.0) | 33 (16.5) | |
| Firewood | 40 (20.0) | 40 (20.0) | |
| Smoker‡(%) | 74 (37.0) | 72 (36.0) | 0.835 |
| Alcohol drinker§ (%) | 66 (33.0) | 61 (30.5) | 0.568 |
| Tea drinker|| (%) | 83 (41.5) | 74 (37.0) | 0.357 |
| Like roasting food# (%) | 118 (59.0) | 100 (50.0) | 0.070 |
| Improved stove use¶ (%) | 149 (74.5) | 171 (85.5) | 0.006 |
‡
Smokers were defined as having smoked at least one cigarette daily for at least 6 consecutive months.
§
Alcohol drinker was defined as having had wine (beer, white wine and red wine) at least once per week for at least 6 consecutive months.
||
Tea drinkers were defined having drank tea at least twice weekly.
¶
Improving the kitchen stove to exclude the fluoride out of the room to decrease the pollution of the air indoors.
#
A habit of roasting food with indoor burning of fluoride-rich coal.